tag:theconversation.com,2011:/global/topics/macular-degeneration-20700/articlesMacular degeneration – The Conversation2023-12-28T09:20:09Ztag:theconversation.com,2011:article/2194412023-12-28T09:20:09Z2023-12-28T09:20:09ZSix ways to look after your eyes in 2024<figure><img src="https://images.theconversation.com/files/564923/original/file-20231211-27-7cymn4.jpg?ixlib=rb-1.1.0&rect=0%2C9%2C6523%2C4342&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/portrait-mature-man-fitting-o-1832804689">Inside Creative House/Shutterstock</a></span></figcaption></figure><p>The World Health Organization estimates that <a href="https://www.who.int/news/item/09-10-2003-up-to-45-million-blind-people-globally---and-growing">over 80%</a> of all vision impairment around the world can be prevented and even cured. Reducing the risk of eye diseases involves adopting a combination of lifestyle changes, protective measures, and regular eye care. Here are six ways to look after your eyes in 2024. </p>
<h2>1. Have regular eye tests</h2>
<p>Many eye diseases don’t have symptoms – at least, initially. <a href="https://www.nhs.uk/conditions/glaucoma/#:%7E:text=Glaucoma%20is%20a%20common%20eye,not%20diagnosed%20and%20treated%20early.">Glaucoma</a>, for example, will cause irreversible damage to the eye if not picked up early enough as it damages the peripheral visual field to start with. People tend not to notice and merely compensate for this loss of peripheral vision by moving their heads more. </p>
<p>Eye disease linked to diabetes also causes irreversible damage to the eyes without much noticeable vision loss as it damages the <a href="https://www.nhs.uk/conditions/diabetic-retinopathy/#:%7E:text=Diabetic%20retinopathy%20is%20a%20complication,it%20could%20threaten%20your%20sight.">small blood vessels</a> in the eye. </p>
<p>Going for an eye test with a qualified optometrist will enable them to detect eye diseases and refer you to a specialist if needed. Early detection of changes in the eye due to diabetes will reduce the <a href="https://diabetesjournals.org/clinical/article/27/4/140/1721/Diabetic-Retinopathy-Screening-Updatelink">risk of blindness by 60-90%</a>. </p>
<p>And a visit to the optometrist does not necessarily mean you have to fork out for expensive new glasses if your vision hasn’t changed. People in the UK qualify for <a href="https://www.nhs.uk/nhs-services/opticians/free-nhs-eye-tests-and-optical-vouchers/">free NHS eye tests</a> if they are over 60 or under 18 years, have a family history of glaucoma, or receive certain state benefits. </p>
<h2>2. Check your eyes at home</h2>
<p>As most of us use both eyes at the same time, it can be difficult to know if one is not seeing so well. Try covering each eye every week and look at a number plate in the distance to make sure both eyes are seeing well. </p>
<p>Differences between the two eyes will affect your depth perception, which then ends up with you not being able to judge how far a person is when driving. </p>
<p><a href="https://www.nhs.uk/conditions/age-related-macular-degeneration-amd/">Age-related macular degeneration</a> usually affects one eye earlier than the other. And the “wet” type – caused by tiny blood vessels at the back of the eye leaking fluid – needs to be treated as soon as possible to avoid any further damage. </p>
<p>Use graph paper held at a near distance, wearing near glasses if you need them, and if lines appear to be wavy or missing, seek an appointment with your optometrist. </p>
<h2>3. Protect your eyes from mechanical and UV damage</h2>
<p>Ultraviolet light can damage the macula, the most central and important part of the eye. Make sure you wear good quality sunglasses that block 100% of UVA and UVB rays to protect your eyes from harmful ultraviolet radiation. </p>
<p>If you are a DIY enthusiast, it’s really important to wear safety goggles. In the summer, gardening accidents, such as getting caught in the eye with a twig when pruning are quite frequent and can cause permanent damage.</p>
<p>Playing squash and other sports without adequate protection can also cause permanent damage. A squash ball is just a bit smaller than the orbit of the eye and this can cause a lot of damage to the soft tissues within the eye as the orbital wall cannot stop the ball’s entry into the eye. </p>
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<img alt="Woman wearing sunglasses" src="https://images.theconversation.com/files/564933/original/file-20231211-15-nslvhc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/564933/original/file-20231211-15-nslvhc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/564933/original/file-20231211-15-nslvhc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/564933/original/file-20231211-15-nslvhc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/564933/original/file-20231211-15-nslvhc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=425&fit=crop&dpr=1 754w, https://images.theconversation.com/files/564933/original/file-20231211-15-nslvhc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=425&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/564933/original/file-20231211-15-nslvhc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=425&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Wear good-quality sunglasses.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-shot-stylish-young-woman-sunglasses-459775861">Jacob Lund/Shutterstock</a></span>
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<h2>4. Reduce digital eye strain</h2>
<p>Excessive exposure to computers and smartphones can lead to eyestrain. While eyestrain does not normally cause permanent damage or affect your glasses prescription, it can be very uncomfortable. </p>
<p>Most people forget to blink when they are working on screens, and this leads to dry eyes. To reduce this discomfort, try consciously blinking more often during screen time. </p>
<p>It helps keep your eyes moist and reduces that tired, dry feeling. You can set a reminder on your phone for blinking exercises where you forcibly blink at least ten times every hour. </p>
<p>Regular breaks will not only give your eyes a rest but will also give your back a rest, too. Remember the <a href="https://www.rnib.org.uk/your-eyes/how-to-keep-your-eyes-healthy/eye-safety/#:%7E:text=Taking%20frequent%20breaks%20from%20the,cause%20you%20to%20need%20spectacles.">20-20-20 rule</a>: every 20 minutes, take a 20-second break, and look at something 20 feet away.</p>
<h2>5. Have a good diet</h2>
<p>While many of us know that vitamin A from carrots is good for the eyes, our eyes need <a href="https://www.medicalnewstoday.com/articles/326758">more than vitamin A</a> to function healthily. </p>
<p>Vitamin C found in citrus fruits, strawberries, bell peppers and broccoli helps protect the eyes from oxidative damage as does vitamin E found in nuts, seeds, spinach and fortified cereals. </p>
<p>Green leafy vegetables have been shown to reduce the risk of macular damage, which is the <a href="https://www.cdc.gov/visionhealth/resources/features/macular-degeneration.html#:%7E:text=AMD%20is%20a%20major%20cause,to%2088%20million%20in%202050.">leading cause of blindness</a> in the elderly. </p>
<p>A healthy diet is also linked to good control of diabetes, and poor control of diabetes will lead to a much higher risk of blindness from diabetic-related eye disease. </p>
<h2>6. Quit smoking and be more active</h2>
<p>Smoking is a significant risk factor for most systemic diseases in the body <a href="https://www.fda.gov/tobacco-products/health-effects-tobacco-use/how-smoking-can-contribute-vision-loss-and-blindness">including the eyes</a>. Smoking increases the risk of macular degeneration and cataracts. Quitting can be tough, but your eyes will appreciate it in the long run. </p>
<p>Exercise is not only important for the rest of the body but also for the eyes. Outdoor activity is a <a href="https://www.sciencedirect.com/science/article/pii/S0161642007013644?via%3Dihub">significant protective factor</a> against the progression of myopia (shortsightedness) in children. </p>
<p>Physical activity increases blood circulation to the eyes, which is essential for delivering oxygen and nutrients to the eyes and removing waste products. It has also been linked to reducing the risk of <a href="https://www.sciencedirect.com/science/article/pii/S0002939417302180?via%3Dihub">age-related macular degeneration</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/29610523/">diabetic retinopathy and glaucoma</a>. </p>
<p>Physical activity is also essential for controlling diabetes, which reduces the risk of blindness in patients with this condition. It is important to note that physical activity is not just about joining a gym. It can involve free activities, including brisk walking, which would be a wonderful opportunity to spend time with family and reduce the progression of myopia in our children.</p><img src="https://counter.theconversation.com/content/219441/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span><a href="mailto:shahina.pardhan@aru.ac.uk">shahina.pardhan@aru.ac.uk</a> receives funding from various NHS bodies, Charities and EU. </span></em></p>Your eyes are your windows on the world. Here’s how to stop them getting smudgy.Shahina Pardhan, Professor of Optometry, Anglia Ruskin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1967962023-02-01T03:12:36Z2023-02-01T03:12:36ZMacular diseases cause blindness and treatment costs millions. Here is how to look after yours<figure><img src="https://images.theconversation.com/files/505792/original/file-20230123-38684-3kz8jx.jpg?ixlib=rb-1.1.0&rect=29%2C24%2C3245%2C2450&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/macular-degeneration-retina-isolated-600w-192688028.jpg">Shutterstock</a></span></figcaption></figure><p>The single most expensive drug for the Australian government today, costing more than <a href="https://www.pbs.gov.au/info/statistics/expenditure-prescriptions/pbs-expenditure-and-prescriptions-report-30-june-2021">A$400 million per year</a>, is one called <a href="https://www.ncbi.nlm.nih.gov/books/NBK582136/">aflibercept</a>. It stops the growth and “leakiness” of blood vessels, and is given to treat a range of different eye diseases. These diseases have one thing in common: they all affect a piece of tissue inside the eye called the macula.</p>
<p>The macula is a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1270903/">structure</a> that distinguishes us humans, as well as some other primates including apes and monkeys. It is a part of the retina that lets us recognise people’s faces, navigate a car and read the newspaper. Our eye is built to focus images onto the macula to achieve this level of vision.</p>
<p>Like the rest of the retina, the macula consists of cells that detect light – <a href="https://www.aao.org/eye-health/anatomy/photoreceptors#:%7E:text=Special%20cells%20in%20the%20eye's,photoreceptor%20cells%3A%20rods%20and%20cones.">photoreceptors</a> – plus nerve cells and other supporting cells, but they are arranged differently to ensure <a href="https://pubmed.ncbi.nlm.nih.gov/21413391/">images are seen</a> in high resolution. The macula also contains the highest body concentration of yellow <a href="https://www.healthline.com/health/carotenoids#benefits">carotenoid pigments</a> – protective antioxidants which <a href="https://pubmed.ncbi.nlm.nih.gov/27847637/">filter out blue light</a> to hone vision.</p>
<p>Scientists are working to understand why so many diseases and conditions, including diabetes, inflammation and parasitic infection, <a href="https://pubmed.ncbi.nlm.nih.gov/29148528/">affect the macula</a>. This is likely due to a host of factors: from the special anatomy of cells, to blood supply, the need for carotenoid pigments and a high metabolic rate.</p>
<h2>The many causes of macular disease</h2>
<p>When a person’s macula becomes diseased, they often experience changes in vision. However, because the macula is just one part of the retina, even severe macular disease generally does not cause complete loss of sight.</p>
<p>Dame Judi Dench has <a href="https://www.theguardian.com/culture/2021/feb/25/you-find-a-way-judi-dench-on-working-through-sight-loss">talked</a> about her macular disease – macular degeneration – including how friends help her learn lines by repeating them over and over to her, and how fellow performers help her know where to face when she is acting. Having this condition might mean she no longer drives a car, but she continues to live a full life.</p>
<p>Macular degeneration affects about <a href="https://www.mdfoundation.com.au/about-macular-disease/age-related-macular-degeneration/amd-overview/">one in seven people</a> over 50 years of age, and can occur as an overgrowth of blood vessels or as a loss of tissue.</p>
<p>Diabetes causes an accumulation of fluid in the macula, called macular oedema; around one in 15 people with diabetes <a href="https://pubmed.ncbi.nlm.nih.gov/22301125/">develop this condition</a>. Other causes of macular oedema include a blocked blood vessel or inflammation inside the eye. It can also be a <a href="https://www.ncbi.nlm.nih.gov/books/NBK576396/">complication</a> after cataract surgery.</p>
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<a href="https://images.theconversation.com/files/506958/original/file-20230130-25-xxwvw6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="older woman with short hair poses for photo on red carpet" src="https://images.theconversation.com/files/506958/original/file-20230130-25-xxwvw6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506958/original/file-20230130-25-xxwvw6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506958/original/file-20230130-25-xxwvw6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506958/original/file-20230130-25-xxwvw6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506958/original/file-20230130-25-xxwvw6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506958/original/file-20230130-25-xxwvw6.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506958/original/file-20230130-25-xxwvw6.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Dame Judi Dench has spoken about how macular degeneration has limited her eyesight.</span>
<span class="attribution"><a class="source" href="https://photos-cdn.aap.com.au/Image/20221010001715263070?path=/aap_dev16/device/imagearc/2022/10-10/b2/e9/8f/aapimage-7n46othvj6x1n1ioe97b_layout.jpg">Vianney Le Caer/Invision/AP</a></span>
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Read more:
<a href="https://theconversation.com/we-could-be-doing-more-to-prevent-vision-loss-for-people-with-diabetes-132086">We could be doing more to prevent vision loss for people with diabetes</a>
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<p>There are many more macular diseases. </p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/14700638/">Toxoplasmosis</a> – a parasite infection – often affects the macula. </p>
<p>Macular disease is a side effect of some drugs, such as hydroxychloroquine used to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2926651/">treat inflammatory diseases</a> like lupus, and the <a href="https://pubmed.ncbi.nlm.nih.gov/26043707/">new immunotherapy drugs</a> for cancers including melanoma.</p>
<p><a href="https://pubmed.ncbi.nlm.nih.gov/12431693/">Central serous chorioretinopathy</a> is a macular disease that affects younger adults and is associated with high levels of the stress hormone <a href="https://pubmed.ncbi.nlm.nih.gov/12431693/">cortisol</a>. Rare inherited conditions can affect the macula even <a href="https://pubmed.ncbi.nlm.nih.gov/28941524/">earlier in life</a>.</p>
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<a href="https://images.theconversation.com/files/505796/original/file-20230123-16-sv3ko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woman shields her eyes from sun on beach" src="https://images.theconversation.com/files/505796/original/file-20230123-16-sv3ko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505796/original/file-20230123-16-sv3ko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505796/original/file-20230123-16-sv3ko5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505796/original/file-20230123-16-sv3ko5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505796/original/file-20230123-16-sv3ko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505796/original/file-20230123-16-sv3ko5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505796/original/file-20230123-16-sv3ko5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Sun protection isn’t just about your skin.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-woman-traveler-wearing-sunglasses-600w-2151827203.jpg">Shutterstock</a></span>
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Read more:
<a href="https://theconversation.com/one-in-three-people-are-infected-with-toxoplasma-parasite-and-the-clue-could-be-in-our-eyes-182418">One in three people are infected with _Toxoplasma_ parasite – and the clue could be in our eyes</a>
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<h2>Treatments and prevention: 5 ways</h2>
<p>Treatments depend on the type of macular disease. Most drugs are given by injection with a fine needle into the back part of the eye, called the <a href="https://www.aao.org/eye-health/anatomy/vitreous">vitreous</a>. This quick procedure may be done in the doctor’s office.</p>
<p>But understanding what the causes of disease have in common points to lifestyle changes that can protect the macula or slow the damage of diseases.</p>
<p><strong>1. Diet</strong></p>
<p>Researchers at the United States National Eye Institute have <a href="https://pubmed.ncbi.nlm.nih.gov/32574780/">shown the benefits</a> of a Mediterranean diet, heavy in legumes and other vegetables, fruits, nuts and whole grains, and favouring fish over red meat, for protection against macular degeneration. A supplement combining vitamin C and E, lutein and zeaxanthin, zinc and copper is also <a href="https://pubmed.ncbi.nlm.nih.gov/32574780/">recommended</a> to limit progression of certain types of degeneration.</p>
<p><strong>2. Avoiding smoking</strong></p>
<p>Not taking up smoking or quitting if you are already a smoker safeguards your macula. <a href="https://pubmed.ncbi.nlm.nih.gov/18321467/">Smoking</a> has been linked to a number of macular diseases, including macular oedema and <a href="https://pubmed.ncbi.nlm.nih.gov/30002072/">central serous chorioretinopathy</a>, as well as <a href="https://pubmed.ncbi.nlm.nih.gov/33958600/">macular degeneration</a>.</p>
<p><strong>3. Sun smarts</strong></p>
<p>Wearing a sunhat and sunglasses from childhood may have benefits beyond skin safety. Some studies suggest sunlight exposure is a risk factor for <a href="https://pubmed.ncbi.nlm.nih.gov/23143904/">macular degeneration</a>. <a href="https://pubmed.ncbi.nlm.nih.gov/29242921/">Physical activity</a> can also protect against this condition, although there is debate about whether vigorous exercise is protective or potentially dangerous.</p>
<p><strong>4. Shut eye</strong></p>
<p>Quality sleep protects the macula. <a href="https://onlinelibrary.wiley.com/doi/10.1111/ceo.14071">Sleep apnoea</a> is associated with several macular diseases, including macular degeneration, macular oedema and central serous chorioretinopathy. Moreover, people with these diseases and untreated sleep apnoea may need <a href="https://pubmed.ncbi.nlm.nih.gov/36054031/">more frequent drug injections</a> for their condition.</p>
<p><strong>5. Busting stress if possible</strong></p>
<p>Limiting stress in life is difficult, but stress is a well-established risk factor for central serous chorioretinopathy. One <a href="https://iovs.arvojournals.org/article.aspx?articleid=2773228">group of US researchers</a> reported an unusually high number of people with the disease at their local health network early in the COVID pandemic, which was a highly stressful time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/505794/original/file-20230123-20-sv3ko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woman waking up and reaching for glasses" src="https://images.theconversation.com/files/505794/original/file-20230123-20-sv3ko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/505794/original/file-20230123-20-sv3ko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/505794/original/file-20230123-20-sv3ko5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/505794/original/file-20230123-20-sv3ko5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/505794/original/file-20230123-20-sv3ko5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/505794/original/file-20230123-20-sv3ko5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/505794/original/file-20230123-20-sv3ko5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Getting enough good quality sleep protects eye health.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/older-mature-woman-holding-taking-600w-1536338495.jpg">Shutterstock</a></span>
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<p>Controlling other aspects of diseases that affect the macula can be important too. For example, the macula benefits from: keeping <a href="https://www.nature.com/articles/s41598-020-61386-4">blood pressure</a> well-controlled, <a href="https://pubmed.ncbi.nlm.nih.gov/32065699/">stabilising blood sugars</a> in people with diabetes, and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6387597/">reducing inflammation</a> in people with uveitis.</p>
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<h2>Check it and see</h2>
<p>You can monitor your own macula using a simple test called the <a href="https://www.mdfoundation.com.au/about-macular-disease/age-related-macular-degeneration/detecting-monitoring-amd/">Amsler grid</a>, available for free online. </p>
<p>Testing with an Amsler grid picks up changes in the vision caused by macular diseases. </p>
<p>Self-testing doesn’t take the place of regular checks with your eye health practitioner. They can examine your macula directly, usually after dilating the pupils, and may employ a powerful technology – <a href="https://www.aao.org/eye-health/treatments/what-is-optical-coherence-tomography">optical coherence tomography</a> – to scan through it.</p><img src="https://counter.theconversation.com/content/196796/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Justine R. Smith receives funding from Macular Disease Foundation Australia, Queensland Eye Institute Foundation, Flinders Foundation and the National Health and Medical Research Council of Australia. </span></em></p>Scientists are figuring out why so many diseases and conditions, including diabetes, inflammation and parasitic infection, can affect our eye health. But there are ways to protect your macula.Justine R. Smith, Professor of Eye & Vision Health, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1805862022-04-19T01:24:06Z2022-04-19T01:24:06ZLonger-acting eye treatment could reduce vision loss for Indigenous Australians<figure><img src="https://images.theconversation.com/files/457284/original/file-20220411-23-z8jc37.jpg?ixlib=rb-1.1.0&rect=36%2C18%2C5907%2C3926&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://image.shutterstock.com/image-photo/woman-looking-refractometer-eye-test-600w-764143345.jpg">Shutterstock</a></span></figcaption></figure><p>Indigenous people in Australia experience <a href="https://healthinfonet.ecu.edu.au/key-resources/publications/?id=35922&title=Review+of+eye+health+among+Aboriginal+and+Torres+Strait+Islander+people">three times more vision loss than non-Indigenous people</a>, creating a concerning <a href="https://mspgh.unimelb.edu.au/__data/assets/pdf_file/0006/1984173/roadmap-summary-september-2015.pdf">gap for vision</a>.</p>
<p>Much of this is due to diabetic macular oedema (DMO). Here, blood vessels in the back of the eye (the retina) are damaged by high blood sugar levels. Over time, this <a href="https://www.mdfoundation.com.au/about-macular-disease/diabetic-eye-disease/about-diabetic-retinopathy/">causes swelling (oedema) of the central part of the retina (the macula)</a>. </p>
<p>Macular oedema blurs the central vision, diminishing the ability to recognise people’s faces, to drive and work, and perform other essential tasks. DMO affects around <a href="https://www.sciencedirect.com/science/article/pii/S0161642016322564">23,000 Indigenous people in Australia</a>, with most of them of working age. Similar trends are reported in other developed states with Indigenous populations, including <a href="https://pubmed.ncbi.nlm.nih.gov/24157988/">New Zealand</a>, <a href="https://pubmed.ncbi.nlm.nih.gov/16043760/">Canada</a> and the <a href="https://pubmed.ncbi.nlm.nih.gov/29924846/">United States</a>.</p>
<p>The good news is DMO is treatable, with medications known as <a href="https://www.mdfoundation.com.au/about-macular-disease/diabetic-eye-disease/treatment-for-diabetic-retinopathy/">anti-VEGF agents</a>. We undertook a world-first <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ceo.14079">clinical trial</a> to test longer-acting DMO treatment for Indigenous Australians. In doing so, we also learned about undertaking culturally sensitive research on Country. </p>
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<strong>
Read more:
<a href="https://theconversation.com/how-can-the-new-closing-the-gap-dashboard-highlight-what-indicators-and-targets-are-on-track-163809">How can the new Closing the Gap dashboard highlight what indicators and targets are on track?</a>
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<h2>A longer-lasting treatment</h2>
<p>When injected into the eye by an ophthalmologist (an eye surgeon), anti-VEGF drugs are safe and effective for treating DMO. The injections don’t hurt, since the eye is anaesthetised. The catch is that anti-VEGF agents are relatively short-acting, requiring them to be re-administered as often as every month. </p>
<p>Many Indigenous patients find it impractical, for complex and varied reasons, to attend <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042588/">ten to 12 eye appointments a year</a>. There is, therefore, a need for an alternative. </p>
<p>Longer-acting medications do exist. One example is a dexamethasone implant (commercially known as <a href="https://www.ozurdex.com/Content/pdf/DME_Patient_Brochure.pdf">Ozurdex(R)</a>), a steroid injected into the eye. The dexamethasone implant only needs to be dosed every three months. </p>
<p>The dexamethasone implant is PBS approved for DMO in Australia but has never been evaluated in an Indigenous population. This is important because a possible side effect of steroid medications is increased pressure in the eye. If left untreated, this can lead to a condition called steroid-induced <a href="https://www.aao.org/eye-health/diseases/what-is-glaucoma">glaucoma</a>. </p>
<p>Glaucoma is thought to occur <a href="https://bjo.bmj.com/content/103/2/191.abstract?casa_token=XV8H0UCusPIAAAAA:CdA9CdW8b4XT2j5xn2NmpQRW2abVqgyftnqBfLl7ssce6jmgyxPQYwt-4_2kEDfOOBgcASlWOEd_">less commonly overall among Indigenous people</a>, suggesting differences in the physiology of eye pressure between Caucasian and Indigenous eyes. Additionally, the incidence of steroid-induced subtype glaucoma has never been studied among Indigenous people. This is particularly important for people in remote locations, since glaucoma is a “silent disease”, requiring regular check ups for detection and treatment. </p>
<p>The <a href="https://www.mja.com.au/journal/2015/203/1/facilitators-and-barriers-implementation-pragmatic-clinical-trial-aboriginal">historical barriers preventing this sort of research</a> include cultural and geographical factors, as well as a lack of endorsement from Indigenous health services and “staff champions”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/458470/original/file-20220419-22-c414kc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woman checks eyes of a second woman" src="https://images.theconversation.com/files/458470/original/file-20220419-22-c414kc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/458470/original/file-20220419-22-c414kc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=497&fit=crop&dpr=1 600w, https://images.theconversation.com/files/458470/original/file-20220419-22-c414kc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=497&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/458470/original/file-20220419-22-c414kc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=497&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/458470/original/file-20220419-22-c414kc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=625&fit=crop&dpr=1 754w, https://images.theconversation.com/files/458470/original/file-20220419-22-c414kc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=625&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/458470/original/file-20220419-22-c414kc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=625&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Kerry Woods, from the clan Plangermairreenner of the Ben Lomond people, is an Aboriginal eye health coordinator involved in the study. She said it gave her ‘insight to the treatments available for diabetic eye disease and the monthly injections required to manage this condition […] Working closely with patients I have the opportunity to yarn about the treatments and if they are happier with the new timeframe.’</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Not just what to research, but how</h2>
<p>At the <a href="https://www.lei.org.au/">Lions Eye Institute</a>, we sought to overcome these barriers with the <a href="https://clinicaltrials.gov/ct2/show/NCT04619303">OASIS Study</a> – a world-first clinical trial in ophthalmology to exclusively recruit Indigenous patients. </p>
<p>We framed our study around ten key factors for success including support from all participating Aboriginal Medical Services, free and safe treatment, free transport, appointment reminders, and cultural safety training for all trial staff. Wherever possible, study visits were performed within patients’ usual Aboriginal Medical Service. Study participants could have friends, family and staff members present. This helped communication and a sense of safety and trust.</p>
<p>Over two years, we recruited 38 Indigenous patients and 52 eyes (some patients had DMO in both eyes). Patients were recruited from both Perth and country Western Australia. On enrolment, they were randomly assigned to receive dexamethasone implant or an anti-VEGF agent called <a href="https://www.aao.org/eye-health/drugs/avastin">Avastin</a>. Follow up was performed for check ups and re-treatments. After 12 months, we analysed all our data, to compare the safety and effectiveness of the two drugs.</p>
<p><a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ceo.14079">The results</a> showed patients who received dexamethasone implant gained four extra letters on a standard eye chart, equivalent to a 6.2% improvement in their vision. Those who received the anti-VEGF agent, meanwhile, lost 5.5 letters on average, representing an 8.9% decline. </p>
<p>Taken together, these results represented a 15% (9.5 letter) visual advantage for patients who received dexamethasone implant. In real world terms, this meant patients met the <a href="https://austroads.com.au/publications/assessing-fitness-to-drive/ap-g56/vision-and-eye-disorders/medical-standards-for-licensing-11">visual requirements for a private driver’s license</a>. Those who received the anti-VEGF agent did not. </p>
<p>This disparity was most pronounced in country towns, where dexamethasone implant had a 37% (24 letter) advantage over the anti-VEGF agent. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/457286/original/file-20220411-13-h1gbu6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="map of WA with dot identifiers" src="https://images.theconversation.com/files/457286/original/file-20220411-13-h1gbu6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/457286/original/file-20220411-13-h1gbu6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/457286/original/file-20220411-13-h1gbu6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/457286/original/file-20220411-13-h1gbu6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/457286/original/file-20220411-13-h1gbu6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/457286/original/file-20220411-13-h1gbu6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/457286/original/file-20220411-13-h1gbu6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Trial participants came from all over Western Australia.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Why it works</h2>
<p>As we suspected, the reason for the dexamethasone implant’s better performance related to its less frequent, hence more pragmatic, dosing regime. </p>
<p>Over 12 months, patients who were meant to receive four dexamethasone implant injections, received an average of 3.3 injections. This meant that, on average, they received 82.5% of their intended treatments.</p>
<p>Anti-VEGF patients, meanwhile, received 7.2 of their scheduled 12 injections. This equated to only 60% of their intended treatments, and reflects the difficulty of attending monthly appointments in the real world. Anti-VEGF patients had more than twice as many injections as dexamethasone implant patients, yet ended up with poorer vision.</p>
<p>Not all the results were positive. One third of patients who received dexamethasone implant developed high pressure in the eye – a recognised side effect of steroid injections. While not painful, this requires treatment with pressure-lowering drops and close follow up, to prevent <a href="https://www.aao.org/eye-health/diseases/what-is-glaucoma">glaucoma</a>. </p>
<p>Secondly, steroid injections speed up <a href="https://www.aao.org/eye-health/diseases/what-are-cataracts">cataract</a> formation (a clouding of the lens in the eye). This requires access to cataract surgery, which is not always simple to arrange in remote locations. Based on these caveats, we developed guidelines for the judicious use of dexamethasone implant among Indigenous patients, <a href="https://onlinelibrary.wiley.com/doi/abs/10.1111/ceo.14079">published in March</a>.</p>
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<p>
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<strong>
Read more:
<a href="https://theconversation.com/a-new-way-to-keep-first-nations-people-with-dementia-connected-to-country-community-family-and-culture-171293">A new way to keep First Nations people with dementia connected to Country, community, family and culture</a>
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<h2>Reducing the burden, closing the vision gap</h2>
<p>While dexamethasone implants are not perfect, we believe the OASIS Study provides hope for reducing vision loss and the “burden of treatment” for Indigenous Australians with diabetes. </p>
<p>The ability to perform culturally safe clinical trials means new treatments may be similarly evaluated in the future, with consideration given to input from patients through <a href="https://findanexpert.unimelb.edu.au/scholarlywork/1415807-building-trust-and-sharing-power-for-co-creation-in-aboriginal-health-research--a-stakeholder-interview-study">community-controlled research</a>.</p>
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Read more:
<a href="https://theconversation.com/racism-is-a-public-health-crisis-but-black-death-tolls-arent-the-answer-176453">Racism is a public health crisis – but Black death tolls aren't the answer</a>
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<img src="https://counter.theconversation.com/content/180586/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This study was funded by Allergan Australia Pty Ltd which produces the treatment Ozurdex mentioned in this article. None of the authors received personal payment. The funder had no role in study design, data collection, data analysis, data interpretation, or writing of the report. </span></em></p>Our study found a better way to treat eye problems in Indigenous communities – and some key considerations for undertaking culturally safe clinical trials.Hessom Razavi, Associate professor, The University of Western AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1606832021-06-01T16:39:57Z2021-06-01T16:39:57ZMacular degeneration is a leading cause of blindness. Here’s how to prevent it<figure><img src="https://images.theconversation.com/files/399869/original/file-20210510-18-1hk45fb.jpg?ixlib=rb-1.1.0&rect=2%2C0%2C1347%2C667&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Macular degeneration can result in blurred or no vision in the center of the visual field. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/">(Shutterstock)</a></span></figcaption></figure><p>Jacques was a very active retiree. That ended one November morning as his life was suddenly turned upside down. When he woke that day, he could not see out of one eye. Panicked, he came to see me right away. </p>
<p>Jacques had been diagnosed with age-related macular degeneration (AMD) a few years earlier. His condition had been stable, but now it suddenly progressed to the most severe form of the disease, “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3404137/">wet degeneration</a>.” This stage is characterized by the sudden development of a network of new blood vessels that ooze into the deep layers of the retina, causing a rapid loss of functional vision in the affected eye.</p>
<p>An urgent referral to ophthalmology is made in cases like these because the window of opportunity for treatment is narrow. Immediate treatment usually results in <a href="https://www.aao.org/preferred-practice-pattern/age-related-macular-degeneration-ppp">the best prognosis</a>. Jacques managed to get treatment within a few days.</p>
<p>The ophthalmologist gave him <a href="https://www.cochrane.org/CD005139/EYES_anti-vascular-endothelial-growth-factor-neovascular-age-related-macular-degeneration">intraocular injections</a> of medication, but this only improved his vision slightly. Jacques was depressed and his anxiety was increasing. He felt useless and had lost considerable autonomy.</p>
<p>The loss of an eye is a traumatic event, regardless of the patient’s age. While the significant negative psychological effects are well documented for <a href="https://pubmed.ncbi.nlm.nih.gov/26893539/">older patients</a>, recent publications also report the same adverse consequences in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5328297/">younger populations</a>.</p>
<p>For example, the rate of depression is six times greater in those with significant vision loss than in the general population (<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2792986/">25 per cent versus four per cent</a>).</p>
<h2>Hope for patients</h2>
<p>So what can we do to help Jacques? We can’t promise that his vision will be fully restored. Although injection treatments can be effective, the basic degeneration will not go away. The best option for Jacques is to refer him to a visual impairment rehabilitation centre where he will receive help from a variety of professionals.</p>
<p>At this centre, he will be seen by specialists trained to treat visual impairment and its repercussions on the lives of people who suffer from it, and on the people around them. Understanding this reality is the first step toward helping patients address their needs.</p>
<p>The next step, after providing psychological support to Jacques, is to optimize his visual condition. Optometrists who specialize in low vision can prescribe optical aids to help Jacques regain some of his visual function, including magnifiers, vision aids and specialized glasses that can be provided through a government program designed for this purpose.</p>
<p>Specialists in visual impairment rehabilitation (VIR) trained at the school of optometry of the University of Montréal (the only institution in Canada that offers a master’s program in VIR), can then help Jacques learn new strategies to carry out his daily activities. Specialized educators can help him to use a computer and specific software. When needed, orientation and mobility specialists teach people with visual impairments methods how to safely orient themselves and get around whether on the street or in an unfamiliar environment.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/391277/original/file-20210323-18-1nq7b4v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391277/original/file-20210323-18-1nq7b4v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391277/original/file-20210323-18-1nq7b4v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391277/original/file-20210323-18-1nq7b4v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391277/original/file-20210323-18-1nq7b4v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391277/original/file-20210323-18-1nq7b4v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391277/original/file-20210323-18-1nq7b4v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Age-related macular degeneration (AMD) can result in blurred or no vision in the centre of the visual field.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<p>A social worker, aware that the impacts of a visual handicap go far beyond the person experiencing it, will accompany Jacques during his rehabilitation process and communicate with his family. In short, Jacques will have a good support system and will be able to regain a certain level of autonomy in his life, which, in turn, will have a positive impact on his morale. <a href="http://www.aqdm.org/home.html">Support groups</a> can also help him in his efforts and if, thanks to effective injections, his visual acuity improves, he will be in a win-win situation.</p>
<p>However, Jacques still has other concerns about his disease. He is worried that his children will develop similar conditions, especially one of his sons.</p>
<h2>Several risk factors</h2>
<p>Age-related macular degeneration is aptly named: its prevalence increases with the age of the patients. Nearly one million Canadians — 300,000 in Québec alone — suffer from AMD. Of these, <a href="https://www.inesss.qc.ca/fileadmin/doc/INESSS/Rapports/DMLA/Note_informative_DMLA.pdf">10 to 15 per cent have the wet form</a>, like Jacques. AMD is the leading cause of blindness in people over the age of 65.</p>
<p>In addition to aging, other risk factors associated with the development of the disease include family history, ethnic origin (white people are more affected), gender (women are more affected), atherosclerotic and vascular diseases, obesity and sun exposure (phototoxicity of the retinal cells).</p>
<p>Smoking also plays an important role. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3866712/">Consuming 25 cigarettes per day</a> doubles the risk of severe damage. Exposure to second-hand smoke is also harmful. The chemicals absorbed during exposure to smoke <a href="https://pubmed.ncbi.nlm.nih.gov/30426163/">increase the absorption of harmful sunlight by the retina by 1,000 times</a>.</p>
<p>For Jacques’ son, the risk of developing AMD is clear but so are his options. He will not be able to change his genes, prevent himself from aging or change his ethnicity or chromosomes. However, he can control the modifiable factors: he can quit smoking, control his weight and stay physically active.</p>
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<p>
<em>
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À lire aussi :
<a href="https://theconversation.com/glaucoma-visions-silent-killer-113878">Glaucoma: Vision's silent killer</a>
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<p>Diet can play a preventive role. Reducing fat intake in the diet and ensuring adequate omega-3 consumption (forms of triglyceride, 800 mg DHA/EPA per day) <a href="https://pubmed.ncbi.nlm.nih.gov/18779490/">are important</a>. However, adding vitamins formulated for eye health to the mix is not recommended in Jacques’ case. Vitamins are only effective in treating dry AMD in its middle stages, not for preventing it. However, they are one of the few ways Jacques can reduce the risk of having his other eye affected and losing all his functional vision.</p>
<p>It is imperative for both Jacques and his son to follow the doctor’s recommendations on managing vascular problems (hypertension, cholesterol, diabetes). When poorly controlled, these conditions significantly increase the risk of developing wet AMD.</p>
<p>Remember, macular degeneration is first and foremost a vascular disease: the blood vessels are no longer able to nourish the retinal cells and no longer get rid of their metabolic waste efficiently. As a result, the cells die. New blood vessels develop, but they are fragile and, when they break, flood the retina with fluid.</p>
<p>Finally, both father and son will need to protect themselves from the sun’s harmful rays, either with a transparent filter (UV400) in their regular prescription glasses or by wearing good quality sunglasses when they are outdoors. Their eye care professionals will be able to advise them about this.</p>
<p>Jacques’ spirits are not high, but I have given him some hope that better days lie ahead. He knows he can count on a team of professionals to support him and that he will not be dealing with his condition alone. There is hope. And hope is the first thing that makes it possible to overcome the impacts of any disease.</p><img src="https://counter.theconversation.com/content/160683/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Langis Michaud ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Age-related macular degeneration (AMD) lives up to its name: Its prevalence increases with age and it is the leading cause of blindness in people over 65 years old.Langis Michaud, Professeur Titulaire. École d'optométrie. Expertise en santé oculaire et usage des lentilles cornéennes spécialisées, Université de MontréalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1298982020-01-15T03:44:20Z2020-01-15T03:44:20ZBushfire smoke is bad for your eyes, too. Here’s how you can protect them<figure><img src="https://images.theconversation.com/files/310124/original/file-20200115-151880-optgd3.jpg?ixlib=rb-1.1.0&rect=0%2C15%2C3524%2C2330&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">When the hazardous particles found in bushfire smoke come into contact with our eyes, this can cause inflammation.</span> <span class="attribution"><span class="source">From shutterstock.com</span></span></figcaption></figure><p>As we continue to contend with smoke haze in various parts of the country, many Australians may find themselves with watery, burning, irritated or red eyes.</p>
<p>Data from countries with consistently poor air quality suggest there could also be a risk of longer term effects to our eyes, particularly with prolonged exposure to bushfire smoke.</p>
<p>Although <a href="https://www.health.nsw.gov.au/environment/air/documents/protect-yourself-from-bushfire-smoke.pdf">P2/N95 masks</a> can protect us from inhaling harmful particles, unfortunately they can’t protect our eyes.</p>
<p>But there are certain <a href="https://www.optometry.unsw.edu.au/sites/default/files/documents/Bushfires%20and%20your%20eyes%202020%20Advice%20Sheet%20FINAL%20%281%29.pdf">things you can do</a> to minimise irritation and the risk of any longer term effects.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-know-bushfire-smoke-affects-our-health-but-the-long-term-consequences-are-hazy-129451">We know bushfire smoke affects our health, but the long-term consequences are hazy</a>
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</em>
</p>
<hr>
<h2>Irritation in the short term</h2>
<p>The eye’s surface is continuously exposed to the environment, except when our eyes are shut when we sleep. </p>
<p>Bushfire smoke contains dust, fumes (such as carbon monoxide and nitrogen oxides), and <a href="https://www.health.nsw.gov.au/environment/air/Pages/particulate-matter.aspx">tiny particles</a> called PM10 and PM2.5.</p>
<p>When the smoke comes into contact with our eyes, the fumes and small particles dissolve into our tears and coat the eye’s surface. In some people, this can trigger inflammation, and therefore irritation.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/bushfire-smoke-is-everywhere-in-our-cities-heres-exactly-what-you-are-inhaling-129772">Bushfire smoke is everywhere in our cities. Here's exactly what you are inhaling</a>
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</p>
<hr>
<p>The presence of a marker called matrix metalloproteinase-9, or MMP-9, indicates the eye is inflamed. </p>
<p>During periods of poor air quality from bushfires in the United States, MMP-9 was present in the eyes of <a href="https://www.healio.com/ophthalmology/cornea-external-disease/news/online/%7Bb8dad2b8-5df1-4412-a5f2-886a099210bb%7D/poor-air-quality-associated-with-dry-eye">more people</a> than it ordinarily would be.</p>
<h2>Longer term risks</h2>
<p>We know very little about how pollution from bushfire smoke might affect our eyes over the longer term, or what damage repeated or chronic exposure might do. </p>
<p>But we do know people who live in areas with high levels of air pollution, such as China, are <a href="https://translational-medicine.biomedcentral.com/articles/10.1186/s12967-019-1794-6">three to four times more likely</a> to develop dry eye. </p>
<p>Dry eye is a condition where a person <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/dry-eye">doesn’t have enough tears or they are of such poor quality</a> they don’t lubricate and nourish the eye. We need high quality tears to maintain the health of the front surface of the eye and provide clear vision.</p>
<p>For people who already have dry eyes – often older people – poor air quality may <a href="https://www.sciencedirect.com/science/article/pii/S0269749118304056?via%3Dihub">increase the damage</a>. The smoke and pollution may cause intense stinging and a feeling of grittiness to the point they can barely open their eyes.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/310130/original/file-20200115-93792-yumjkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/310130/original/file-20200115-93792-yumjkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/310130/original/file-20200115-93792-yumjkb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/310130/original/file-20200115-93792-yumjkb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/310130/original/file-20200115-93792-yumjkb.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/310130/original/file-20200115-93792-yumjkb.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/310130/original/file-20200115-93792-yumjkb.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Avoid rubbing your eyes, as this could make the irritation worse.</span>
<span class="attribution"><span class="source">From shutterstock.com</span></span>
</figcaption>
</figure>
<p>While dry eye is a result of damage to the surface of the eyes, it’s also possible pollutants entering the blood stream after we breathe them in could affect the blood supply to the eye. This in turn could damage the fine vessels within the eye itself.</p>
<p>Research has suggested high levels of air pollution in Taiwan may increase the risk of <a href="https://jim.bmj.com/content/67/7/1076">age-related macular degeneration</a>, which could be an example of this. </p>
<p>We need more research into the long-term effects on our eyes of prolonged poor air quality, particularly from bushfire smoke. But what we do know suggests it’s possible bushfire smoke could be causing subtle damage to the eyes, even in people without any symptoms.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/even-for-an-air-pollution-historian-like-me-these-past-weeks-have-been-a-shock-129141">Even for an air pollution historian like me, these past weeks have been a shock</a>
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</em>
</p>
<hr>
<h2>What can you do to protect your eyes from the smoke?</h2>
<ul>
<li>the best option is to avoid going outside when air quality is at is worst, where possible</li>
<li>wearing sunglasses or glasses when outside if you need them might stop some of the dust carried in the wind from contacting the eye’s surface (but it won’t stop the tiny particles getting in)</li>
<li>avoid wearing contact lenses if possible.</li>
</ul>
<h2>Some tips if your eyes are irritated</h2>
<ul>
<li>flush your eyes as often as you can, with over-the-counter <a href="https://www.aao.org/eye-health/treatments/lubricating-eye-drops">lubricant eye drops</a> if you have some on hand. If not, use sterile saline solution or clean bottled water</li>
<li>if your eyes are itchy, flush them and then place a cool face washer over your closed lids</li>
<li>don’t rub your eyes, as this could make the irritation worse.</li>
</ul>
<p>If your eyes are red and sore and these steps don’t help, it’s best to see an eye care professional.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/from-face-masks-to-air-purifiers-what-actually-works-to-protect-us-from-bushfire-smoke-128633">From face masks to air purifiers: what actually works to protect us from bushfire smoke?</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/129898/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katrina Schmid receives funding from Carl Zeiss Vision Germany</span></em></p><p class="fine-print"><em><span>Isabelle Jalbert received or receives funding from the Australian Government Office for Learning and Teaching, the Macular Diseases Foundation Australia, Johnson & Johnson Vision Care Inc., and Alcon Laboratories (Australia).</span></em></p>Another troubling consequence of the bushfire smoke is its effects on our eyes. But there are some steps we can take to minimise irritation and any risk of longer term harms.Katrina Schmid, Associate Professor, Queensland University of TechnologyIsabelle Jalbert, Associate Professor, School of Optometry and Vision Science, UNSW Sydney, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1268952019-11-13T23:26:04Z2019-11-13T23:26:04ZFrom cataracts to macular degeneration: Age-related eye problems and how to treat them<figure><img src="https://images.theconversation.com/files/301388/original/file-20191112-178506-poyu44.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1356%2C667&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cataracts are a vision problem that can affect anybody as they age. It happens when the lens of the eye gradually loses its transparency. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/">Shutterstock</a></span></figcaption></figure><p>Monique is 77 years old. I met her when she came to the eye clinic at the University of Montréal, where I am a professor. A retired teacher, Monique has enjoyed an active and full life with her students and family and considers herself lucky to be in good health. </p>
<p>She is concerned, however, about a recent visual loss that prevents her from reading and enjoying her painting workshops. It also prevents her from driving safely, which is important if she wants to maintain her independence.</p>
<p>A complete examination of Monique’s vision and eye health quickly revealed the cause of her problems: she has developed cataracts and her retina shows early signs of macular degeneration. </p>
<p>Cataracts are a normal phenomenon, resulting from the aging process of the eye and affecting everyone, without exception. They occur when the <a href="https://www.mayoclinic.org/tests-procedures/cataract-surgery/about/pac-20384765">lens of the eye gradually loses its transparency</a>, like a window that gets dirty with the seasons.</p>
<p>The light that enters the eye passes through opaque areas and generates blurred vision, without the possibility of improving it with glasses, lenses or magnifiers. Only surgery can restore the clarity of the eye. </p>
<h2>The aging of the crystalline lens</h2>
<p>The crystalline lens is particular and its metabolism is very fragile. When disturbed, the lens accumulates deposits and loses its transparency. This lens also absorbs a large part of the sun’s ultraviolet rays to protect the retina at the back of the eye. </p>
<p>The amount of UV absorbed accumulates over the years, contributing to the premature aging of the lens. That is why it is recommended to protect yourself with sun lenses from an early age. </p>
<hr>
<p>
<em>
<strong>
À lire aussi :
<a href="https://theconversation.com/summer-is-here-why-you-need-to-protect-your-childrens-eyes-116498">Summer is here! Why you need to protect your children's eyes</a>
</strong>
</em>
</p>
<hr>
<p>Other factors that disrupt its functioning include the use of certain medications such as oral cortisone, the presence of diseases such as diabetes or a shock to the head, which can contribute to the arrival and progression of cataracts. Very rarely, cataracts are transmitted during pregnancy, especially <a href="https://www.ncbi.nlm.nih.gov/pubmed/6964280">following infections </a>such as rubella, toxoplasmosis and herpes. </p>
<p>Finally, very strong links have been established between <a href="https://www.sciencedirect.com/science/article/abs/pii/S0886335005005274">smoking and cataracts</a>. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5452183/">Food</a>, on the other hand, does not seem to have an impact. Quitting smoking and protecting your eyes with good sunglasses are therefore considered effective ways to delay the onset and progression of cataracts. </p>
<h2>Implants to the rescue</h2>
<p>Cataract treatment is quite simple. The ophthalmologist will perform surgery to exchange the natural lens of the eye with a new lens, called an implant. This surgery is very safe and can be performed at any time during cataract development, although surgery will usually only be offered if there is a significant impact on the patient’s vision and quality of life. </p>
<p>Implants are permanent and remain clear for life, without the need for replacement. They can be used to correct distance vision, including astigmatism, which would be accomplished through the use of a specially designed toric implant. Also, nearsightedness can be fixed via bifocal or multifocal implants, thus avoiding the need for glasses later on, <a href="https://www.cochrane.org/CD003169/EYES_multifocal-versus-monofocal-intraocular-lenses-people-having-cataract-surgery">in most cases</a>. </p>
<p>However, the patient may be subject to seeing halos and may be more sensitive to light. It is also necessary to ensure that the retina is in good health, otherwise the final result will not be very good. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/289236/original/file-20190823-170951-zjz8dq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/289236/original/file-20190823-170951-zjz8dq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289236/original/file-20190823-170951-zjz8dq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289236/original/file-20190823-170951-zjz8dq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289236/original/file-20190823-170951-zjz8dq.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289236/original/file-20190823-170951-zjz8dq.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289236/original/file-20190823-170951-zjz8dq.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Very strong links have been found between smoking and macular degeneration.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>This is particularly the case for Monique, who also has the onset of age-related macular degeneration (AMD). This is a phenomenon affecting one per cent of people exceeding 40 years of age, but whose <a href="https://doi.org/10.1016/j.jfo.2009.04.009">prevalence reaches 30 per cent at 80 years of age.</a></p>
<p>The at-risk population is composed of Caucasians (those of European origin) and women more than men. Systemic diseases — everything that affects blood vessels such as diabetes, high blood pressure, high cholesterol and obesity — are important risk factors, as are <a href="https://www.ncbi.nlm.nih.gov/pubmed/27125062">oxidative causes such as smoking, high saturated fat nutrition and UV exposure</a>. </p>
<h2>Prevent macular degeneration</h2>
<p>Essentially, the best retinal cells, which allow good vision (macular area), degrade over time if not well nourished by the vascular network and <a href="https://www.mayoclinic.org/diseases-conditions/dry-macular-degeneration/symptoms-causes/syc-20350375">accumulate deposits that prevent their normal functioning</a>.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/289235/original/file-20190823-170927-yo74n2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/289235/original/file-20190823-170927-yo74n2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/289235/original/file-20190823-170927-yo74n2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/289235/original/file-20190823-170927-yo74n2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/289235/original/file-20190823-170927-yo74n2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/289235/original/file-20190823-170927-yo74n2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/289235/original/file-20190823-170927-yo74n2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Light exercises, such as walking, may be enough to delay the progression of macular degeneration.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>These deposits become visible as <a href="https://www.ncbi.nlm.nih.gov/books/NBK315804/">small yellow spots</a> at the fundus — the part of the eyeball opposite the pupil. These deposits, known as drusen, can become confluent. The degradation of cells is accompanied by a change in their colouring (pigment reworking), a phenomenon that is also visible when the retina is examined. This is called dry macular degeneration. Vision is more or less affected depending on the number of affected cells. </p>
<p>Over time, the system’s response can lead to the formation of new blood vessels to supply dying cells. These are fragile and have no real place to stay. They can easily burst. Their membrane formation, like roots invading a pipe, and their flow (bleeding) contribute to a very severe reduction in vision. This is when we speak of <a href="https://www.cos-sco.ca/vision-health-information/conditions-disorders-treatments/retinal-diseases/amd/">wet degeneration</a>. This more severe form affects 10 per cent of AMD cases, but anyone with the dry form can progress at this stage. </p>
<h2>Nutritional supplements</h2>
<p>AMD treatments are limited and aim to limit the progression of the disease. They cannot cure it. Quitting smoking, good nutrition, regular exercise and following the doctor’s recommendations in the control of vascular diseases such as diabetes and hypertension, can delay the progression of the dry form of AMD. </p>
<p>Wearing sunglasses also helps, even on cloudy days. Taking <a href="https://www.ncbi.nlm.nih.gov/pubmed/18779490">omega 3</a> at the right dosage and fish oil extracts may help although <a href="https://www.dx.doi.org/10.1001/jama.2013.4997">more recent results</a> have called this strategy into question. </p>
<p>In more advanced stages of the dry form, <a href="http://dx.doi.org/10.1155/2014/901686">taking oral nutritional supplements</a> including vitamins and antioxidants are recommended, except in some patients with a <a href="https://doi.org/10.1155/2017/6469138">particular genetic profile</a>. </p>
<p>The wet form has recently been effectively treated by injecting drugs directly into the eye, to prevent the formation of new blood vessels. These injections must be repeated periodically and restore vision when the procedure is performed at <a href="https://www.ncbi.nlm.nih.gov/pubmed/27220225">the appropriate time</a>. </p>
<p>Monique’s case is a mixed one. On the one hand, it is possible to greatly improve her short-term vision with cataract surgery, for which she will be referred to ophthalmology. Implants protect against UV rays, another factor in preventing the progression of macular degeneration. This will allow her to drive safely and resume her activities. She will also monitor her diet, which she admits is deficient, and take omega supplements. Her AMD is at a stage that is too early for vitamins or antioxidants.</p>
<p>Monique does not smoke and is not taking medication for vascular problems. If she does one day, she will follow her doctor’s recommendations and begin a light exercise program. Walking may be enough. Finally, she will be followed every six months in an optometry office, will perform simple <a href="https://www.aao.org/eye-health/tips-prevention/facts-about-amsler-grid-daily-vision-test">home screening tests</a> and will come in for a consultation as soon as a change is noted. </p>
<p>Monique is reassured! She will be able to remain active and independent to enjoy the good times of life. </p>
<p>[ <em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/126895/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Langis Michaud ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>Cataracts, which can be experienced by anyone as they age, happen when the lens of the eye gradually becomes less transparent. There are ways, however, to correct this.Langis Michaud, Professeur Titulaire. École d'optométrie. Expertise en santé oculaire et usage des lentilles cornéennes spécialisées, Université de MontréalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1242352019-10-11T13:03:57Z2019-10-11T13:03:57ZBlue light isn’t the main source of eye fatigue and sleep loss – it’s your computer<figure><img src="https://images.theconversation.com/files/296496/original/file-20191010-188807-u4v7v7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">While blue light has been blamed for sleep loss, it's not the only bad light.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/man-front-computer-screen-dark-night-11514280?src=BLyrJPAqyFp0jEYxevcAxA-1-6">Chaoss/Shuttterstock.com</a></span></figcaption></figure><p>Blue light has gotten a bad rap, <a href="https://www.forbes.com/sites/fionamcmillan/2018/08/11/how-blue-light-damages-cells-in-your-eyes/">getting blamed for loss of sleep and eye damage</a>. Personal electronic devices <a href="https://doi.org/10.3389/fpubh.2015.00233">emit more blue light than any other color</a>. Blue light has a short wavelength, which means that it is high-energy and can damage the delicate tissues of the eye. It can also pass through the eye to the retina, the collection of neurons that converts light into the signals that are the foundation of sight.</p>
<p>Laboratory studies have shown that prolonged exposure to high-intensity blue light <a href="https://www.sciencedirect.com/science/article/pii/S1011134409000025?via%3Dihub">damages retinal cells</a> in mice. But, epidemiological <a href="https://doi.org/%2010.1016/j.ophtha.2004.10.047">studies on real people</a> tell a different story. </p>
<p>As an <a href="https://scholar.google.com/citations?user=thGgi2UAAAAJ&hl=en">assistant professor at The Ohio State University</a> College of Optometry, I teach and conduct vision research, including work with retinal eye cells. I also see patients in the college’s teaching clinics. Often, my patients want to know how they can keep their eyes healthy despite looking at a computer screen all day. They often ask about “blue-blocking” spectacle lenses that they see advertised on the internet. </p>
<p>But when it comes to protecting your vision and keeping your eyes healthy, blue light isn’t your biggest concern.</p>
<h2>Built-in protection</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/296516/original/file-20191010-188814-2yoh66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/296516/original/file-20191010-188814-2yoh66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/296516/original/file-20191010-188814-2yoh66.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/296516/original/file-20191010-188814-2yoh66.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/296516/original/file-20191010-188814-2yoh66.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/296516/original/file-20191010-188814-2yoh66.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/296516/original/file-20191010-188814-2yoh66.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Sunlight has more blue light than your computer.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-portrait-beautiful-african-american-woman-387806866?src=W0qyo74vYxTxbsOSZ4sWfw-1-13">miamgesphotography/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>One way to think about blue light and potential retinal damage is to consider the Sun. <a href="https://www.intechopen.com/books/biofuels-economy-environment-and-sustainability/the-possibility-of-future-biofuels-production-using-waste-carbon-dioxide-and-solar-energy">Sunlight</a> is mostly blue light. On a sunny afternoon, it’s nearly <a href="https://doi.org/10.7554/eLife.15392">100,000 times brighter</a> than your computer screen. Yet, few human studies have found <a href="https://jamanetwork.com/journals/jamaophthalmology/fullarticle/268111">any link</a> between sunlight exposure and the development of age-related macular degeneration, a retinal disease that leads to loss of central vision.</p>
<p>If being outside on a sunny afternoon likely doesn’t damage the human retina, then neither can your dim-by-comparison tablet. A theoretical study recently <a href="https://doi.org/10.1038/eye.2015.261">reached the same conclusion</a>.</p>
<p>So, why the disconnect between blue light’s effects on rodent eyes and human eyes?</p>
<p>Human eyes are different than rodent eyes. We have protective elements, such as <a href="https://doi.org/10.1038/sj.eye.6702780">macular pigments</a> and the natural blue-blocking ability of the <a href="https://doi.org/10.1113/jphysiol.1988.sp016935">crystalline lens</a>. These structures absorb blue light before it reaches the delicate retina. </p>
<p>That doesn’t mean you should throw away those sunglasses; they provide benefits beyond protecting your eyes from the Sun’s blue light. For example, wearing sunglasses <a href="https://doi.org/%2010.1074/jbc.M114.554410">slows down the development of cataracts</a>, which cloud vision.</p>
<h2>Feeling the blues</h2>
<p>Just because blue light isn’t harming your retina doesn’t mean your electronic devices are harmless, or that blue light doesn’t affect your eyes. Because of its wavelength, blue light does <a href="https://doi.org/10.1523/JNEUROSCI.21-16-06405.2001">disrupt healthy sleep physiology</a>. <a href="https://doi.org/10.1126/science.1067262">Blue-light-sensitive</a> cells, known as known as intrinsically photosensitive retinal ganglion cells, or ipRGCs, play a key role here, because they tell the brain’s master clock how light it is in the environment. That means, when you look at a brightly lit screen, these cells help set your internal clock for daytime-level alertness. </p>
<p>But these cells are sensitive to colors beyond blue because they also receive input from <a href="https://www.physiology.org/doi/full/10.1152/physrev.00013.2010?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed">other retinal neurons</a> that are sensitive to the entire color spectrum. </p>
<p>Therefore, eliminating blue light alone doesn’t cut it when it comes to improving sleep; you need to dim all colors.</p>
<p>As for your tired eyes after a long day spent staring at your computer – another common complaint I hear from my patients – blue light isn’t solely to blame for that, either. A recent study demonstrated that cutting blue light alone <a href="https://doi.org/10.1097/OPX.0000000000001318">did not improve</a> people’s reported comfort after a long computer session any more than simply dimming the screen. </p>
<h2>Does blocking the blue make sense?</h2>
<p>Many patients want to know if they should buy certain products they have seen advertised to block out blue light. Based on research, the short answer is “no.” </p>
<p>First, the truth is that any bright light too close to bedtime interferes with sleep.</p>
<p><a href="https://doi.org/10.1073/pnas.1418490112">Mounting evidence</a> suggests that, compared to reading a paperback, screen time before bed increases the time it takes to fall asleep. It also robs you of restorative rapid-eye-movement sleep, dulls focus and diminishes brain activity the next day. Holding your phone close to your eyes with the lights on likely <a href="https://doi.org/10.1038/srep11325">exacerbates the problem</a>.</p>
<p>Second, the products that my patients ask about do not block out much blue light. The leading blue-blocking anti-reflective coating, for example, <a href="https://doi.org/10.1097/OPX.0000000000001393">blocks only about 15%</a> of the blue light that screens emit.</p>
<p>You could get the same reduction just by holding your phone another inch from your face. Try it now and see if you notice a difference. No? Then it shouldn’t surprise you that a recent meta-analysis concluded that blue-blocking lenses and coatings have <a href="https://doi.org/10.1111/opo.12406">no significant effect</a> on sleep quality, comfort at the computer, or retinal health.</p>
<h2>What really works</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/296512/original/file-20191010-188823-19v26go.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/296512/original/file-20191010-188823-19v26go.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/296512/original/file-20191010-188823-19v26go.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/296512/original/file-20191010-188823-19v26go.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/296512/original/file-20191010-188823-19v26go.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/296512/original/file-20191010-188823-19v26go.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/296512/original/file-20191010-188823-19v26go.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Computers cause eye strain because people don’t blink as often when staring at a screen.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-woman-taking-off-glasses-tired-1075401764?src=kSqTmRfglJpQ53eQzQoDGQ-1-18">fizkes/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>There are ways to make your screen viewing more comfortable and more conducive to sleep. </p>
<p>First, turn off your electronic devices before bed. The <a href="https://www.aap.org/en-us/about-the-aap/aap-press-room/Pages/American-Academy-of-Pediatrics-Announces-New-Recommendations-for-Childrens-Media-Use.aspx">American Academy of Pediatrics</a> recommends that bedrooms be “screen-free” zones for children, but we should all heed this advice. Outside of the bedroom, when you do look at your screens, lower the brightness. </p>
<p>As for eye strain, ensure that you have the appropriate glasses or contact lens prescription. Only an optometrist or ophthalmologist can give you this information.</p>
<p>You also need to take care of the surface of your eyes. We don’t just look at our computer screens, we stare at them. In fact, our <a href="https://doi.org/10.1007/s00417-003-0786-6">blink rate plummets</a> from about 12 blinks a minute to six. As a result, tears evaporate off the eyes, and they don’t accumulate again until we step away from the screen and start blinking. This causes inflammation on the eye’s surface. That’s why your eyes feel dry and tired after a day spent at the computer. I counsel my patients to take two steps to ensure that their eyes stay moist during long computer sessions.</p>
<p>First, follow the “20-20-20” rule. The <a href="https://www.aoa.org/documents/infographics/SYVM2016Infographics.pdf">American Optometric Association</a> defines this rule as taking a 20-second break every 20 minutes to look at something 20 feet in the distance. This will allow your eyes to blink and relax. There are many apps available to help remind you to follow this rule.</p>
<p>Second, use a lubricating eye drop before extended computer use. This tactic will reinforce the body’s natural tears and keep the eye’s surface hydrated. But, avoid those “get-the-red-out” drops. They contain drugs that cause long-term redness and preservatives that may <a href="https://www.sjeyeassociates.com/the-dangers-of-redness-relief-eye-drops/">damage the outer layers of the eye</a>. I have found that artificial tears labeled “preservative free” often work best.</p>
<p>Based on my research, my advice is don’t believe the hype about blue light and don’t waste your money on products you don’t need. Instead, keep screens out of your bedroom and dim them before bedtime and keep your eyes lubricated. And don’t forget to blink!</p>
<p>[ <em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/124235/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Phillip Yuhas receives funding from the National Institutes of Health and the Ohio Lions Eye Research Foundation. He is a member of the American Optometric Association, the Ohio Optometric Association, the American Academy of Optometry, and the Association for Research in Vision and Ophthalmology. </span></em></p>Blue light has been getting blamed for sleep interruption and eye strain. But the facts are that any bright light interferes with sleep, and computers themselves cause eye strain, an eye doctor says.Phillip Yuhas, Assistant Professor of Optometry, The Ohio State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1224272019-09-26T21:29:29Z2019-09-26T21:29:29ZPoor vision: Do drivers always see what is happening on the road?<figure><img src="https://images.theconversation.com/files/293675/original/file-20190923-54813-9e0ufe.jpg?ixlib=rb-1.1.0&rect=102%2C87%2C4469%2C2646&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Vision is the most important source of information on which driving conduct is based. Poor vision of drivers has been found to be the cause of many accidents.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/">Shutterstock</a></span></figcaption></figure><p>A <a href="https://www.cbc.ca/news/canada/montreal/highway-330-bonnardel-1.5247853">recent tragic pile-up on a major highway near Montreal</a> has spurred the Québec government into action — to find the best ways to improve roads and prevent such disasters from happening again.</p>
<p>However, this investigation into the crashes on Highway 440 which left four people dead did not mention the main tool for safe driving — vision.</p>
<p>The <a href="https://www.ncbi.nlm.nih.gov/pubmed/24563119">Cochrane Institute published an analysis in 2014</a> indicating that vision is the most important source of information on which to assess driving. Poor vision of drivers is one of the causes of many accidents.</p>
<p>The potential causes of vision impairment are well known: cataracts, macular degeneration, diabetic retinopathy, glaucoma and corneal scars, to name a few. In addition, there are binocular vision problems (visual coordination) that can lead to unstable, double vision, lack of third dimensional perception and<a href="https://www.ncbi.nlm.nih.gov/pubmed/21870915"> delayed reaction to an unexpected event</a>, such as a child appearing in front of the car.</p>
<p>Finally, refractive errors are also very present. <a href="https://www.mayoclinic.org/diseases-conditions/farsightedness/symptoms-causes/syc-20372495">Uncorrected hyperopia (farsightedness) can lead to drowsiness while driving</a>. A myopic and/or astigmatic person who does not wear his glasses while driving — it often happens, believe it or not — does not see well into the distance, at least not to a safe distance allowing him to anticipate incidents.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/288539/original/file-20190819-123720-xsve0g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/288539/original/file-20190819-123720-xsve0g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/288539/original/file-20190819-123720-xsve0g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/288539/original/file-20190819-123720-xsve0g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/288539/original/file-20190819-123720-xsve0g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/288539/original/file-20190819-123720-xsve0g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/288539/original/file-20190819-123720-xsve0g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Binocular vision problems can lead to unstable, double vision, lack of perception of the third dimension, as well as a delayed reaction to an unexpected event, such as a child who appears in front of the car.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Young people also affected</h2>
<p>Although the incidence of visual pathologies and problems increases with age, some of them also impact younger drivers. More than 200,000 Québecers are affected by a combination of <a href="http://www.vision2020canada.ca/en/resources/Pages/default.aspx">all types of eye problems</a>. That suggests that each time you venture onto the road, you are likely to encounter a driver who is affected by an eye or visual impairment that puts his or her driving at risk.</p>
<p>In addition to visual acuity, other elements of visual function contribute to safe driving. For example, <a href="https://www.ncbi.nlm.nih.gov/pubmed/12517356">the visual function includes an intrinsic element of perception</a>. That allows you to grasp a scene that takes place in front of your eyes with the best possible clarity, your eye movements allowing you to appreciate the dynamics of the scene. The study of visual function — and not just visual acuity — is therefore essential to reducing the number of accidents.</p>
<p>Mosty eye problems or <a href="https://www.ncbi.nlm.nih.gov/pubmed/25000871">abnormalities of oculo-visual function are asymptomatic</a> and are only detected during a complete examination by an optometrist. This is particularly the case with diabetic retinopathy or ocular lesions, already present in <a href="http://guidelines.diabetes.ca/Browse/Chapter30">25 per cent of patients at the time of diagnosis</a>.</p>
<h2>Lax regulations</h2>
<p>While science confirms the importance of vision to safe driving, regulatory agencies treat this element negligently. They only require often inappropriate or late checks on the visual condition of drivers. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/288536/original/file-20190819-123749-48rhyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/288536/original/file-20190819-123749-48rhyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/288536/original/file-20190819-123749-48rhyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/288536/original/file-20190819-123749-48rhyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/288536/original/file-20190819-123749-48rhyv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/288536/original/file-20190819-123749-48rhyv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/288536/original/file-20190819-123749-48rhyv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Although science confirms the importance of vision for safe driving, regulatory agencies are often lax about this element.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>For example, the screening test conducted in the service centres of the <a href="https://saaq.gouv.qc.ca/en/">Société de l'assurance automobile du Québec</a> (the Québec auto insurance board) when a temporary permit is issued is very brief and neglects fundamental aspects of eye health. The SAAQ requires more comprehensive tests much later for the majority of drivers.</p>
<p>In the case of private vehicles (classes 5 and 6), the examination is required at age 75 and then from age 80, every two years. For commercial vehicles (classes 1 to 4), if driving involves a presence in the United States, an examination is required every five years until age 45, then every three years from age 45 to 65. However, if the driver lives in the rest of Canada, his or her examination is generally only required at age 45, then every five years from age 55 to 65 and every two years thereafter. </p>
<p>The provinces, which follow National Safety Code standards and the <a href="https://ccmta.ca/images/pdf-documents-english/CCMTA-Medical-Standards-2017-English.pdf">Canadian Council of Motor Transport Administrators Medical Standards for Drivers</a>, also add other conditions in certain circumstances as well. For example, Ontario and Alberta require vision testing when a driver requests a change in the classification of their licence. Ontario also requires vision testing when a licence has been expired for more than a year or when an optometrist advises of any issues with a driver’s vision. </p>
<p>There is no reason for such varying standards. The risk is the same everywhere. Although periodic inspection of drivers from the age of 45 is happening, it would seem more important to carry out a full assessment of everyone when they apply for a licence.</p>
<h2>Recommendations left unheeded</h2>
<p>Lack of adequate regulation prompted the Ordre des Optométristes du Québec (Quebec Order of Optometrists) to create <a href="https://auto.lapresse.ca/actualites/201703/03/01-5075284-securite-routiere-examen-de-la-vue-obligatoire-des-65-ans-plutot-qua-75-.php">specific recommendations during the provincial transportation ministry’s consultation in 2017</a>. </p>
<p>The Order proposed that the statutory examination for Class 5 and 6 drivers be scheduled for at least 70 years of age, and possibly even 65 years. It also suggested that statutory examination for commercial drivers (Class 1 to 4) be applied in the same way, whether or not the driver drives in the United States. The examination of these drivers should include a complete eye and visual examination.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/288538/original/file-20190819-123727-wu3ykn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/288538/original/file-20190819-123727-wu3ykn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/288538/original/file-20190819-123727-wu3ykn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/288538/original/file-20190819-123727-wu3ykn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/288538/original/file-20190819-123727-wu3ykn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/288538/original/file-20190819-123727-wu3ykn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/288538/original/file-20190819-123727-wu3ykn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The Order of Optometrists recommends that the statutory audit examination be moved to age 65, instead of age 75 as is currently the case.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>The Order also proposed that assessment tests conducted at the time of obtaining a driver’s licence should not be limited but should cover the detection of abnormalities in refraction, <a href="https://www.ncbi.nlm.nih.gov/pubmed/20385890">visual field</a>, binocular vision and screening for eye diseases that may influence driving. </p>
<p>These recommendations, which have not yet been adopted by the authorities, are scientifically justified. They are also full of common sense, insofar as we must be concerned about the safety of road users and in order to improve the driving record in Quebec.</p>
<h2>It’s time to act</h2>
<p>By recognizing vision as a key element of safe driving, policy makers and public agencies would make a significant contribution to improving road conditions across the country. </p>
<p>Drivers themselves must be proactive by consulting their eye-care professional on a regular basis. They must comply with their recommendations. They must also adequately treat any ocular or visual condition that could lead to sight loss or dysfunction of visual perception.</p>
<p>[ <em>Deep knowledge, daily.</em> <a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/122427/count.gif" alt="La Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Langis Michaud ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son organisme de recherche.</span></em></p>When you head out onto the road, there’s always a chance that you might encounter a driver who has a vision problem, putting his or her driving at risk. Regulations need to change.Langis Michaud, Professeur Titulaire. École d'optométrie. Expertise en santé oculaire et usage des lentilles cornéennes spécialisées, Université de MontréalLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/924122018-02-28T15:08:55Z2018-02-28T15:08:55ZCuring blindness with stem cells – here’s the latest science<figure><img src="https://images.theconversation.com/files/207834/original/file-20180226-122025-lvjau9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/539698657?src=jD-5idkMTgvRJ_GNciXy6g-1-6&size=medium_jpg">Vic29</a></span></figcaption></figure><p>In 2006, Nature published a paper describing how stem cells could be used to <a href="https://www.nature.com/articles/nature05161">restore sight in blind mice</a>. This study, and similar subsequent studies, <a href="http://news.bbc.co.uk/1/hi/health/6120664.stm">created a lot of excitement</a> about the potential of stem cells to cure blindness in humans. Fast forward 12 years and we still don’t seem to be quite there – one notable human clinical trial in Japan was stopped in 2015 due to a <a href="https://ipscell.com/2015/07/firstipscstop/">risk of tumour development</a> in a patient’s eye. So are we any closer to using stem cell therapies to treat blindness, or will we always be “ten years away”?</p>
<h2>Eye spy</h2>
<p>The retina is an important tissue at the back of the eye that senses light and sends visual information to the brain. Eye diseases such as <a href="https://www.nhs.uk/conditions/glaucoma/">glaucoma</a> and <a href="https://www.nhs.uk/conditions/macular-degeneration/">macular degeneration</a> are characterised by damage to retina cells, which can eventually lead to vision loss and blindness. Scientists hope to find a way to replace or preserve damaged retina cells in order to treat these eye diseases.</p>
<p>Stem cells might be useful for this because they can be triggered to turn into any type of cell. In 2010 scientists successfully <a href="https://www.researchgate.net/publication/44577817_Immortalized_Human_Fetal_Retinal_Cells_Retain_Progenitor_Characteristics_and_Represent_a_Potential_Source_for_the_Treatment_of_Retinal_Degenerative_Disease">guided stem cells into becoming retina cells</a> in a laboratory. It is hoped that these cells could later be delivered into the diseased eye to replace or preserve damaged retina cells.</p>
<p>Although scientists have previously had success isolating and maintaining retina stem cells in the laboratory, there is still more work to do before these cells can be routinely delivered to patients for treatment. The first big challenge is figuring out how treatments can safely be delivered into the patient’s eye in the right location. The eye is such a small and fragile organ that injection needles and surgery may cause even greater damage to the eye.</p>
<p>Once a delivery method has been established, the next challenge is deciding how to get the stem cells to communicate with existing retina cells and function properly inside the eye. Getting this to happen is not easy and <a href="https://theconversation.com/stem-cells-show-promise-but-they-also-have-a-darker-side-75029">there are risks</a> that the stem cells may not function correctly and could cause problems, such as inflammation and tumour development, inside the eye.</p>
<p>In addition to these hurdles, scientists also need to overcome the challenge of immune rejection. In the same way that the body might reject a new heart after transplant surgery, stem cells might also get rejected by the body. Stem cell therapies developed from a patient’s own cells have a reduced chance of immune rejection, though they may be more expensive and time consuming to develop. For stem cell therapies developed from donor cells, drugs such as immunosuppressants are likely to be needed.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/207835/original/file-20180226-120971-l0ye4g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/207835/original/file-20180226-120971-l0ye4g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=352&fit=crop&dpr=1 600w, https://images.theconversation.com/files/207835/original/file-20180226-120971-l0ye4g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=352&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/207835/original/file-20180226-120971-l0ye4g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=352&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/207835/original/file-20180226-120971-l0ye4g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=442&fit=crop&dpr=1 754w, https://images.theconversation.com/files/207835/original/file-20180226-120971-l0ye4g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=442&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/207835/original/file-20180226-120971-l0ye4g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=442&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/327062306?src=17BRzdC7__UnetbtmQhgNA-1-1&size=medium_jpg">Tefi/Shutterstock</a></span>
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<h2>Building miniature scaffolds</h2>
<p>In order to overcome these challenges, one approach scientists are investigating is the use of biomaterials. Biomaterials are typically materials that have been modified to interact with biological systems. It is hoped that these materials could be used to improve the delivery of stem cell therapy, as well as the integration with existing cells once inside the eye.</p>
<p>An example of this is the use of biomaterial scaffolds. As the name suggests, these are scaffolding-like structures that cells can hold onto in order to improve their chances of growth and survival. Scientists have already successfully developed biomaterial scaffolds that closely resemble the environment of retina tissue. </p>
<p>Attaching the stem cells to these scaffolds before delivery into the eye may improve their chances of communicating with existing cells and functioning correctly once inside. This technique has been successful in <a href="http://online.liebertpub.com/doi/10.1089/ten.tea.2013.0720">studies with mice</a> and some <a href="https://clinicaltrials.gov/ct2/show/NCT02903576?term=stem+cells+scaffold&cond=Macular+Degeneration&rank=1">human clinical trials</a> are already in progress.</p>
<p>Therefore despite the challenges, scientists continue to look for ways to treat debilitating eye diseases. The eye is an incredibly complex and fragile organ, which is why research in this area may take a bit longer than for other parts of the body.</p>
<p>There are still hurdles that need to be overcome, such as the delivery technique of stem cells, their integration with existing cells once inside the eye and the chance of immune rejection. However, ongoing research into the use of biomaterials to improve stem cell integration has had promising results and may overcome some of these initial challenges.</p>
<p>So with continued support of this field of research we can be hopeful that, if the latest clinical trials run successfully, a cure for blindness using stem cells could finally be possible within the next ten years.</p><img src="https://counter.theconversation.com/content/92412/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Rachel Gater receives PhD studentship funding from Keele University ACORN fund and Faculty of Medicine & Health Sciences.</span></em></p>Stem cell treatments for eye disease always seem to be just on the horizon, but real progress is being made.Rachel Gater, PhD Candidate, Keele UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/865192017-10-31T05:20:39Z2017-10-31T05:20:39ZDo vitamin supplements prevent macular degeneration?<figure><img src="https://images.theconversation.com/files/192570/original/file-20171031-18686-1bg19e6.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There's evidence vitamins can slow the progression of existing macular degeneration. </span> <span class="attribution"><span class="source">from www.shutterstock.com</span></span></figcaption></figure><p>Vitamin and mineral supplements <a href="https://www.ncbi.nlm.nih.gov/pubmed/28756617">won’t prevent the development of age-related macular degeneration</a>. But there is some evidence taking supplements containing vitamin C, vitamin E and zinc may <a href="https://www.ncbi.nlm.nih.gov/pubmed/28756618">slow the progression of age-related macular degeneration</a> in those who already have it. This evidence comes from two major systematic reviews published this year, conducted by the <a href="http://www.cochranelibrary.com/">Cochrane collaboration</a>. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-age-related-macular-degeneration-59889">Explainer: what is age-related macular degeneration?</a>
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</em>
</p>
<hr>
<p>The reason researchers thought about testing dietary supplements for eye disease relates to <a href="https://www.nkcf.org/about-keratoconus/how-the-human-eye-works/">how the eyes convert light into sight</a>. Light gets absorbed into pigments in the retina at the back of the eye. This process produces byproducts called free radicals. <a href="https://www.livescience.com/54901-free-radicals.html">Free radicals are oxygen atoms that have unpaired electrons</a>, which makes them highly reactive and unstable. As these atoms hunt around to find another electron so they can become more stable, they trigger damage to other molecules, the walls of cells and to DNA. In the eyes, this contributes to gradual loss of vision.</p>
<p><a href="https://www.betterhealth.vic.gov.au/health/healthyliving/antioxidants">Anti-oxidants are nutrients that absorb free radicals</a> and include vitamin A, C and E, the minerals zinc and selenium, and many phytonutrients found in edible plants including vegetables and fruit. Theoretically if more anti-oxidant nutrients were present in the eye, less damage should be done to the eye. Lets look at what the scientific evidence says.</p>
<p>The <a href="https://www.ncbi.nlm.nih.gov/pubmed/28756618">first review</a> looked at people who already had age-related macular degeneration and includes research published up until March 2017. They found 19 trials in adults who already had early or moderate macular degeneration. Nine studies compared people taking vitamin supplements to those either not taking them or being given a placebo (dummy) capsule for periods of time from nine months to six years. </p>
<p>They found the vitamin supplements were associated with 28% lower odds of progressing to late stage macular degeneration. The studies that compared zinc supplements to a placebo found a 17% lower risk of progressing to late stage macular degeneration. </p>
<p>The authors final conclusion cautiously suggested use of antioxidant vitamin and mineral supplements may help delay disease progression in people with existing age-related macular degeneration, with a reminder that while vitamin supplements are generally safe they can have harmful effects in some, <a href="https://www.ncbi.nlm.nih.gov/pubmed/18429004">such as smokers</a>.</p>
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<strong>
Read more:
<a href="https://theconversation.com/mondays-medical-myth-take-a-vitamin-a-day-for-better-health-8482">Monday’s medical myth: take a vitamin a day for better health</a>
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<p>The second review looked at <a href="https://www.ncbi.nlm.nih.gov/pubmed/28756617">prevention of age-related macular degeneration</a>. There were four trials that compared taking Vitamin E to a placebo which found vitamin E had no effect on prevention of age-related macular degeneration. And one trial found a side-effect of an increase in risk of haemorrhagic stroke in those taking vitamin E.</p>
<p>Two studies used beta-carotene (an organic compound found in plants that the body converts into Vitamin A) and found no reduction in risk of new onset macular degeneration with one study confirming <a href="https://www.ncbi.nlm.nih.gov/pubmed/8127329">an increased risk of lung cancer in the smokers</a>. </p>
<p>One study in men compared vitamin C or multivitamins with a placebo and found no effect for vitamin C and a slightly higher risk for age-related macular degeneration in the group taking the multivitamins. There was no evidence related to other antioxidants such as lutein or zeaxanthin.</p>
<p>Loss of vision due to age-related macular degeneration is associated with a loss of ability to do the things that help to improve your nutrition related health and well-being as you age. Compared to adults of a similar age and sex who did not have age-related macular degeneration, those with it have a <a href="https://www.ncbi.nlm.nih.gov/pubmed/28665868">higher risk of death from heart disease and all other causes</a>.</p>
<p>It’s wise to trying and boost your <a href="https://www.ncbi.nlm.nih.gov/pubmed/19335941">diet quality for a host of reasons</a>, by eating more healthily as you age and trying to <a href="http://www.quitnow.gov.au/">quit smoking</a>. You can use our free <a href="http://healthyeatingquiz.com.au/">Healthy Eating Quiz</a> to check your score.</p>
<p>Meanwhile, try to increase you intake of foods rich in phytonutrients. Oysters, meat, eggs, seafood, nuts, tofu, legumes, wheat germ and wholegrain foods contain zinc. Oranges, mandarins, lemons, limes, strawberries, kiwifruits, tomato, capsicum, spinach, broccoli, cabbage and green vegetables contain vitamin C. Nuts, seeds, wheatgerm and eggs contain vitamin E. Egg yolk, corn, spinach, pumpkin, cucumber, kiwifruit, red grapes, zucchini, capsicum, oranges and mangoes contain the antioxidants lutein and zeaxanthin. </p>
<p>If you’ve been told you have age-related macular degeneration then you should discuss the risks and benefits of supplementation with your doctor. Keep in mind vitamin supplements that include beta-carotene are not recommended if you are a smoker. Remember to talk to your GP about your eye health as you age.</p><img src="https://counter.theconversation.com/content/86519/count.gif" alt="The Conversation" width="1" height="1" />
<h4 class="border">Disclosure</h4><p class="fine-print"><em><span>Clare Collins is affiliated with the Priority Research Centre for Physical Activity and Nutrition, the University of Newcastle, NSW. She is an NHMRC Senior Research and Gladys M Brawn Research Fellow. She has received research grants from NHMRC, ARC, Hunter Medical Research Institute, Meat and Livestock Australia, Diabetes Australia, Heart Foundation. She has consulted to SHINE Australia, Novo Nordisk, Quality Bakers and the Sax Institute. She was a team member conducting the systematic reviews to inform the 2013 revision of the Australian Dietary Guidelines and the 2017 evidence review on dietary patterns and heart disease for the Heart Foundation.</span></em></p>Vitamin and mineral supplements won’t prevent the development of age-related macular degeneration. But there is some evidence taking supplements containing vitamin C, vitamin E and zinc may slow the progression…Clare Collins, Professor in Nutrition and Dietetics, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/797582017-08-16T20:12:39Z2017-08-16T20:12:39ZArtificial vision: what people with bionic eyes see<figure><img src="https://images.theconversation.com/files/180439/original/file-20170801-22164-p32p57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Phosphenes are an experience of seeing light without light entering your eye. Bionic eye recipients use these to map out a visual scene. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/peretzpup/3370468814/in/photolist-7TWxyF-RP8uTf-QAMGzc-47E7AL-icZTc9-uPSsJ-93ehaZ-auvtp-7TmEYh-9tdX4y-5K95g6-SiFhHo-4d6w14-QSXt-5MYScE-49F9zo-5C8Tt-9FZCQh-5ZfgX5-7rd3V7-6fwbdv-c4wRgf-RSgzUb-8YKttZ-49F9Yy-61AzpR-LMMHy-dzWfTc-niko6g-qjStVg-SeZcpT-dqSNLT-eyp8bF-WHC2DU-6oQ6E9-Wuydu1-5Gmmru-oTXhug-dZ8JGD-RBE6Eu-94B33h-68QwXh-TwGZAC-4bxUZq-UZx2t2-9v4YMv-86KfQn-8JV4HL-9awR1V-89fbTn">Eugene Peretz/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Visual prostheses, or “bionic eyes”, promise to provide artificial vision to visually impaired people who could previously see. The devices consist of micro-electrodes surgically placed in or near one eye, along the optic nerve (which transmits impulses from the eye to the brain), or in the brain.</p>
<p>The micro-electrodes stimulate the parts of the visual system still functional in someone who has lost their sight. They do so by using tiny electrical pulses similar to those used in a bionic ear or cochlear implant. </p>
<p>Electrical stimulation of the surviving neurons leads the person to perceive small spots of light called phosphenes. A phosphene is a phenomenon of experiencing seeing light without light actually entering the eye - like the colours you may see when you close your eyes.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/180161/original/file-20170728-32241-1d3j0yj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/180161/original/file-20170728-32241-1d3j0yj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/180161/original/file-20170728-32241-1d3j0yj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/180161/original/file-20170728-32241-1d3j0yj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/180161/original/file-20170728-32241-1d3j0yj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/180161/original/file-20170728-32241-1d3j0yj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=570&fit=crop&dpr=1 754w, https://images.theconversation.com/files/180161/original/file-20170728-32241-1d3j0yj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=570&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/180161/original/file-20170728-32241-1d3j0yj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=570&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">The optic nerve transmits impulses to the brain from the retina at the back of the eye.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
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<p>These phosphenes in someone with a bionic eye can be used to map out the visual scene. So the vision provided by a bionic eye is not like natural sight. It is a series of flashing spots and shapes the person uses to interpret their environment through training - somewhat like a flashing mosaic.</p>
<p>Currently, the vision provided by a bionic eye is very basic and can be used for tasks such as identifying the location of an object, detecting a person, or <a href="http://www.abc.net.au/news/2014-04-30/bionic-eye-patients-start-first-navigation-tests/5422174">finding a doorway</a>. Researchers hope future bionic eye devices will provide higher resolution vision, but this has inherent challenges. </p>
<h2>How the bionic eye works</h2>
<p>A bionic eye converts images from a video camera (left picture below) to a high-contrast representation (middle picture), of which a portion is selected for further processing. This is the blue-shaded box below, corresponding to the reduced field-of-view of a typical bionic eye. </p>
<p>An external video processor then converts this high-contrast image to electrical stimulation parameters, which are sent to electrodes implanted in the eye. The bionic eye recipient perceives a blurred image (right of the picture) comprised of flashes of light.</p>
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<a href="https://images.theconversation.com/files/179393/original/file-20170724-19505-1nx22pe.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/179393/original/file-20170724-19505-1nx22pe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/179393/original/file-20170724-19505-1nx22pe.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=136&fit=crop&dpr=1 600w, https://images.theconversation.com/files/179393/original/file-20170724-19505-1nx22pe.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=136&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/179393/original/file-20170724-19505-1nx22pe.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=136&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/179393/original/file-20170724-19505-1nx22pe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=171&fit=crop&dpr=1 754w, https://images.theconversation.com/files/179393/original/file-20170724-19505-1nx22pe.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=171&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/179393/original/file-20170724-19505-1nx22pe.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=171&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Left - video camera; middle - high contrast representation; right - further processing.</span>
<span class="attribution"><span class="license">Author provided</span></span>
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</figure>
<h2>What recipients actually see</h2>
<p>We know from the experience of our Melbourne patients that activity on the electrodes is <a href="http://iovs.arvojournals.org/article.aspx?articleid=2556019">seen as a series of bright flashes</a> rather than as a steady perception. The world is thus flashing bursts of light arranged to represent the basic shape – like the height and width – and approximate location of an object in front of the camera. Other recipients have <a href="http://www.twincities.com/localnews/ci_28363473/bionic-eye-helps-duluth-man-make-out-his">said this was like</a>:</p>
<blockquote>
<p>looking at the night sky where you have millions of twinkly lights that almost look like chaos.</p>
</blockquote>
<p>Recipients need to use these irregular flashes to interpret the camera image. The field of view (the extent of the observable world) is small – about 30 degrees wide or one hand span at arm’s length – so recipients need to have a good memory to put the whole image together. </p>
<p>Improvements to the external camera and <a href="http://www.afr.com/technology/bionic-vision-a-step-closer-with-the-csiros-new-computing-system-20170717-gxcjgy">video processing</a> are able to assist here. For example, distance-sensing cameras can <a href="http://iopscience.iop.org/article/10.1088/1741-2560/12/1/016003/meta">highlight obstacles</a> such as a rubbish bin on the sidewalk, and thermal cameras can <a href="http://iovs.arvojournals.org/article.aspx?articleid=2563307">highlight human shapes</a>. Right now, the best outcomes rely heavily on patient engagement and rehabilitation.</p>
<h2>Who gets a bionic eye?</h2>
<p>The type of bionic eye that may be an option for patients is dependent on the cause of their vision loss. Retinal bionic eye implants are placed into the eyeball itself, and are only suitable for people who have lost their vision from specific diseases such as inherited types of retinal degeneration known as retinitis pigmentosa and age-related macular degeneration. </p>
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Read more:
<a href="https://theconversation.com/explainer-what-is-age-related-macular-degeneration-59889">Explainer: what is age-related macular degeneration?</a>
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<p>To date, only people with degenerative retinal diseases have been eligible to receive a bionic eye. Three retinal bionic eyes have been approved for commercial sale: the <a href="http://www.secondsight.com/g-the-argus-ii-prosthesis-system-pf-en.html">Argus II</a> developed in the USA, the <a href="https://www.retina-implant.de/en/implant/ri-alpha-ams/">Alpha-AMS</a> in Germany, and the <a href="http://www.pixium-vision.com/en/technology-1/iris-vision-restoration-system">IRIS V2</a> in France. </p>
<p>We ran clinical trial with three people, between 2012 and 2014, using <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0115239">a new device developed in Melbourne</a>, Australia. This device may have a safer surgical profile than existing bionic eyes as it is implanted at the back of the eye rather than inside the eye. </p>
<p>Prior to surgery, the Melbourne patients would not have been able to see a hand waving in front of their face. With the bionic eye implant, they were able to locate objects on a table, and <a href="http://www.abc.net.au/news/2014-04-30/bionic-eye-patients-start-first-navigation-tests/5422174">navigate around objects in their path while walking</a>, demonstrating that the implant could provide useful visual information in the real world. We are preparing for a trial of a <a href="http://bionicvis.com/our-products/">second-generation implant in the next year</a>. These are all retinal implants and have mainly been used for people with retinitis pigmentosa. </p>
<p>Implants placed on either the optic nerve or <a href="http://www.monash.edu/bioniceye">directly into the brain</a> may be able to provide benefit to people with a broader range of conditions, such as trauma or glaucoma. Devices for these particular conditions are <a href="http://investors.secondsight.com/releasedetail.cfm?ReleaseID=995211">still in the research phase</a> but are expected to enter human clinical trials in the near future. </p>
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<strong>
Read more:
<a href="https://theconversation.com/explainer-what-is-glaucoma-the-sneak-thief-of-sight-64807">Explainer: what is glaucoma, the 'sneak thief' of sight?</a>
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<p>The quality of vision with a retinal implant heavily depends on the residual eye health of the patient and the ability to interpret the created phosphenes. The implanted electrodes aim to replicate the function of missing light sensitive cells (photoreceptors). But there must be viable surviving neurons for the electrodes to interact with. </p>
<p>Another complicating factor is that there are many neuron types in the retina but the electrodes are too large to selectively target individual types. For this reason, bionic eyes cannot replicate the sense of colour. In fact, artificial vision is very different from normal vision and takes a lot of getting used to. </p>
<h2>Can image quality be improved?</h2>
<p>At present, there are several approaches to improve image quality. One is to increase the number of implanted micro-electrodes and make them smaller, allowing them to target selective neurons for more independent “pixels” and greater resolution. There are <a href="http://www.sciencedirect.com/science/article/pii/S0142961212005029">newer nanotechnology materials</a> that might allow the electrodes to be small enough to produce high-acuity resolution.</p>
<p>Another technique is to refine the electrical stimulation patterns to better <a href="http://iovs.arvojournals.org/article.aspx?articleid=2529378">focus the stimulation</a> to activate smaller-sized clusters of neurons. We can also artificially increase the resolution by creating “<a href="http://iovs.arvojournals.org/article.aspx?articleid=2212666">virtual electrodes</a>” where electrical current is shared between two or more electrodes. These new stimulation methods could improve stability, reduce blurriness and possibly even provide rudimentary control over colour. </p>
<p>Ultimately, researchers are seeking to understand and <a href="http://www.cell.com/neuron/abstract/S0896-6273(14)00359-6">mimic the neural code</a> the retina uses to communicate with the brain. If the firing patterns of photoreceptors could be replicated, the correct message would be transmitted to the brain. The resulting vision would become significantly more natural.</p>
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Read more:
<a href="https://theconversation.com/some-people-cant-see-but-still-think-they-can-heres-how-the-brain-controls-our-vision-63323">Some people can't see, but still think they can: here's how the brain controls our vision</a>
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<hr>
<p>Combining these techniques, the level of vision attainable might allow patients to independently navigate around without the use of a guide dog or cane. It could be possible to recognise everyday objects or even emotions on faces of loved ones. As to which approach is ultimately feasible, only time will tell. One thing that is certain is bionic eyes will get better over time.</p><img src="https://counter.theconversation.com/content/79758/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Matthew Petoe receives funding from the National Health and Medical Research Council of Australia (NHMRC), the Australian Research Council (ARC), and the Clive and Vera Ramaciotti Foundations.</span></em></p><p class="fine-print"><em><span>Lauren Ayton currently receives funding from the National Health and Medical Research Council of Australia (NHMRC) and the Macular Disease Foundation of Australia. She is also a previous veski Victoria Fellow and Melbourne-Boston Sister Cities Association Hugh Rogers Fellow.</span></em></p><p class="fine-print"><em><span>Mohit Shivdasani receives funding from the National Health and Medical Research Council of Australia (NHMRC) and the Australian Research Council (ARC). </span></em></p>The artificial vision provided by a bionic eye is not like natural sight, and takes a lot of getting used to.Matthew Petoe, Team Leader, Bionic Eye Psychophysics, Bionics InstituteLauren Ayton, Senior research fellow, Department of Surgery (Ophthalmology) University of Melbourne, Centre for Eye Research AustraliaMohit Shivdasani, Senior research fellow, Bionics InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/679302017-01-24T19:18:30Z2017-01-24T19:18:30ZWhy we lose our hearing and vision as we age<figure><img src="https://images.theconversation.com/files/152206/original/image-20170110-12672-15g6ms2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We experience lots of changes in our body as we age, and our eyes and ears are no exception. Unfortunately this toys with our senses. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p><em>This article is part of our series on <a href="https://theconversation.com/au/topics/older-peoples-health-33308">older people’s health</a>. It looks at the changes and processes that occur in our body as we age, the conditions we’re more likely to suffer from and what we can do to prevent them.</em></p>
<hr>
<p>As the baby boomer generation begins to age, the prevalence of both eye and ear disease will rise exponentially, as there is a strong correlation between vision loss, hearing loss and ageing.</p>
<p>The <a href="http://www.who.int/mediacentre/factsheets/fs282/en/">World Health Organisation estimates</a> that 285 million people worldwide are visually impaired, with 82% of people with blindness aged 50 and above. Australia alone will have 800,000 people aged 40 or over with low vision or hearing loss by 2020.</p>
<p>As people age, they often experience a number of changes in their physical, mental and social health. Among these are eye and ear changes, and diseases that usually result in vision and hearing loss. Changes to our eyes and ears occur as a result of disease, genetic factors, “wear and tear” and environmental factors.</p>
<h2>What happens in our eyes as we age?</h2>
<p>There are a range of changes in our eyes that occur as a result of age. For example, over time the whites of the eyes, or “sclera”, undergo changes due to exposure to ultraviolet light. </p>
<p>These changes include a yellowing or browning of the white of the eye due to fatty or cholesterol deposits in the conjunctiva – the mucous membrane that covers the eye – also related to ageing and exposure to ultraviolet light. </p>
<p>Over time, changes also occur in the conjunctiva, such as a thinning of the membrane. This often results in dry eye, a condition caused mainly by reduced production of tears and reduced mucous from the conjunctiva.</p>
<p>As we age, we often experience a decrease in the strength of our muscles. This is no different in the eye, and the muscles in our eyelids can become weaker over time. Reduced tone in the muscle that gives shape to our lens, as well as stiffening of the natural lens with age, causes presbyopia (inability to see near objects), necessitating the use of reading glasses.</p>
<p>Eye disorders that commonly occur in older adults include:</p>
<ul>
<li><p><strong>macular degeneration</strong>. This terms describes <a href="https://theconversation.com/explainer-what-is-age-related-macular-degeneration-59889">damage to the pigmented oval</a> in the centre of the retina resulting in decreased central vision and seeing fine detail. This happens as we age because of deposits of fine grains that build up in the retina.</p></li>
<li><p><strong>Cataracts</strong>. This is a <a href="https://theconversation.com/explainer-what-are-cataracts-63699">clouding of the lens</a> that covers the eye. These are thought to be caused by breakdown and degradation of lens proteins, and are considered a part of the normal ageing of the lens. </p></li>
<li><p><strong>Diabetic retinopathy</strong>. This is damage to the retina resulting from diabetes. Type 2 diabetes is age related and the duration and control of blood glucose levels often determine whether or not diabetic retinopathy does or does not develop.</p></li>
<li><p><strong>Glaucoma</strong>. When <a href="https://theconversation.com/explainer-what-is-glaucoma-the-sneak-thief-of-sight-64807">glaucoma</a> occurs, the optic nerve is progressively damaged resulting in loss of the peripheral visual field.</p></li>
</ul>
<p>Among older Australians, cataract is the most common eye disease and cause of visual impairment (over <a href="https://www.health.gov.au/internet/main/publishing.nsf/Content/D1A5409787D800F2CA257C73007F12F3/%24File/eyehlth.pdf">70% of people in Australia</a> aged 80 years and over have cataracts), followed by age-related macular degeneration (occurring in <a href="http://www.aihw.gov.au/media-release-detail/?id=6442464587">3.1% of older people</a>).</p>
<h2>What happens in our ears as we age?</h2>
<p>As we get older, we experience changes all over our body, including the ears. Commonly, people’s ears (outer ears, that is) become bigger, earwax accumulates more easily and there is more cartilage in the external ear canal.</p>
<p>There is also often a stiffening of the eardrum and <a href="https://www.nursingtimes.net/roles/older-people-nurses/exploring-the-anatomy-and-physiology-of-ageing-part-6-the-eye-and-ear/1840889.article">changes to the neural</a> (nerve) system.</p>
<p>These changes contribute to older people suffering from hearing loss and central <a href="https://theconversation.com/is-your-child-having-trouble-learning-they-may-have-auditory-processing-disorder-62491">auditory processing disorders</a>, in which the ear cannot properly process sounds.</p>
<h2>How these changes affect daily life</h2>
<p>As a result of these numerous eye and ear changes and diseases, older people typically have vision and hearing problems that include sensitivity to light and difficulty visualising distant objects or reading print. </p>
<p>Hearing problems include difficulty with perceiving and discriminating sounds (including speech), understanding speech (particularly in poor listening situations such as when there is high background noise or echo), and processing auditory information.</p>
<p>These difficulties interfere with older adults’ everyday functioning and participation in activities. People with sensory loss may have difficulty performing independent activities of daily living such as bathing and shopping. This means they’re more at risk of problems with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448344/">mental health and social interaction</a>.</p>
<p>One of the most disabling effects of vision and hearing loss is decreased ability to communicate with others. People with severe vision loss (low vision or legal blindness) have difficulty lip reading or perceiving non-verbal cues (such as facial expression or gestures). </p>
<p>Those with hearing loss have communication difficulties including difficulty perceiving sounds or following a conversation. For people with loss of both senses, communication difficulties are much worse. They can’t adequately receive a verbal message and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4030176/">frequently misunderstand conversation</a>.</p>
<h2>Management of sensory loss</h2>
<p>Management of sensory loss requires assessment by professionals (such as optometrists and audiologists) who will recommend the appropriate management plan that may include the use of a visual or hearing device.</p>
<p>Speech pathologists also play a role, with programs including speech perception training or communication programs for clients and carers. </p>
<p>Early identification and intervention can help those with vision and hearing loss so the effects of these sensory losses can be minimised, improving their quality of life.</p>
<hr>
<p><em>Acknowledgement: Dr Julian Sack (Ophthalmologist) for his input. Read other articles in the series <a href="https://theconversation.com/au/topics/older-peoples-health-33308">here</a>.</em></p><img src="https://counter.theconversation.com/content/67930/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chyrisse Heine does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Changes to our eyes and ears occur as a result of disease, genetic factors, “wear and tear” and environmental factors.Chyrisse Heine, Speech Pathologist/Audiologist Senior Lecturer, La Trobe UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/685822016-12-19T00:40:54Z2016-12-19T00:40:54ZHealth Check: will I damage my eyes if I don’t wear sunglasses?<figure><img src="https://images.theconversation.com/files/149184/original/image-20161208-31396-t8ax7r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sunglasses should be worn at all times when outdoors during the day when the UV index is 3 or above.</span> <span class="attribution"><a class="source" href="https://unsplash.com/search/sunglasses?photo=6qzw-entUOw">Amy Humphries/Unsplash</a></span></figcaption></figure><p>The iconic <a href="https://youtu.be/tGgn5nwYtj0">“Slip Slop Slap”</a> campaign was launched in Australia in 1981. Sid the Seagull encouraged people to slip on a shirt, slop on sunscreen and slap on a hat to minimise ultraviolet (UV) radiation exposure and reduce the risk of sunburn and skin cancer. </p>
<p>In 2007, the slogan was updated to <a href="http://www.cancer.org.au/preventing-cancer/sun-protection/campaigns-and-events/slip-slop-slap-seek-slide.html">“Slip Slop Slap Seek Slide”</a>. So now it includes seeking shade and sliding on sunglasses to further reduce the risk of UV-related damage. This emphasises the importance of protecting eyes – and the skin around them – from UV radiation. </p>
<h2>Short-term effects</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/149183/original/image-20161208-31391-1g479v0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149183/original/image-20161208-31391-1g479v0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/149183/original/image-20161208-31391-1g479v0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149183/original/image-20161208-31391-1g479v0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149183/original/image-20161208-31391-1g479v0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149183/original/image-20161208-31391-1g479v0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149183/original/image-20161208-31391-1g479v0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149183/original/image-20161208-31391-1g479v0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Prolonged exposure to the welder’s arcs without eye protection can cause photokeratitis.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>Briefly exposing an unprotected eye to UV rays usually won’t cause any symptoms. </p>
<p>But prolonged or intense UV exposure without eye protection (including to the sun, welder’s arcs, snow and tanning beds) can cause a <a href="http://www.who.int/uv/faq/uvhealtfac/en/index3.html">condition called photokeratitis</a>. </p>
<p>This can be thought of as sunburn of the cornea, the clear window on the front of the eye. UV rays cause death of the outermost layer of cells of the cornea. </p>
<p>This results in severe pain affecting both eyes, which begins six to 12 hours after exposure. </p>
<p>Treatment involves oral painkillers and antibiotic eye ointments (to prevent infection of the damaged cornea) while waiting for the corneal cells to regenerate. </p>
<p>The process takes 24 to 72 hours and people can expect a full recovery with no complications from photokeratitis.</p>
<h2>Long-term effects</h2>
<p>Repeated exposure to UV radiation without adequate eye protection can result in permanent eye damage. Eye diseases associated with chronic UV exposure include the following.</p>
<p><strong>Cataracts</strong></p>
<p>Here, the normally transparent lens of the eye <a href="https://www.ncbi.nlm.nih.gov/pubmed/21617534">becomes cloudy</a>. This causes blurred vision and eventually blindness if untreated. It is <a href="http://www.unep.org/pdf/Solar_Index_Guide.pdf">estimated up to 20% of cataract cases</a> are caused or made worse by UV exposure. </p>
<p>Wearing sunglasses remains one of the most effective ways of preventing <a href="https://theconversation.com/explainer-what-are-cataracts-63699">cataract formation</a>. </p>
<p>When they cause troublesome visual impairment, cataracts require surgical extraction. This costs Australia more than <a href="http://wiki.cancer.org.au/policy/Position_statement_-_Eye_protection">A$320 million a year</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/135769/original/image-20160829-17859-bvfh20.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/135769/original/image-20160829-17859-bvfh20.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=436&fit=crop&dpr=1 600w, https://images.theconversation.com/files/135769/original/image-20160829-17859-bvfh20.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=436&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/135769/original/image-20160829-17859-bvfh20.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=436&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/135769/original/image-20160829-17859-bvfh20.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=547&fit=crop&dpr=1 754w, https://images.theconversation.com/files/135769/original/image-20160829-17859-bvfh20.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=547&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/135769/original/image-20160829-17859-bvfh20.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=547&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Cataracts are one of the leading causes of visual impairment globally.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Cataract_in_human_eye.png">Rakesh Ahuja, MD/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p><strong>Pterygium</strong></p>
<p>This is a <a href="https://www.ncbi.nlm.nih.gov/pubmed/10511020">benign growth of conjunctival tissue</a> on the cornea. The conjunctiva is the transparent membrane overlying the sclera (the white part of the eye) and usually does not cover the cornea. Although non-cancerous, the presence of a pterygium can cause chronic irritation, redness and inflammation. </p>
<p>Pterygia grow slowly over months and years and can obstruct vision when they grow over the pupil. They may also induce astigmatism (an improper curvature of the cornea), which blurs vision. </p>
<p>Treatment for mild pterygia not affecting vision involves lubrication with artificial tears. Those that affect vision may require surgical excision. </p>
<p>Again, chronic UV exposure to unprotected eyes is a <a href="https://www.ncbi.nlm.nih.gov/pubmed?term=10684840">major cause of pterygium development</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149200/original/image-20161208-31385-1tnilkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149200/original/image-20161208-31385-1tnilkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149200/original/image-20161208-31385-1tnilkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149200/original/image-20161208-31385-1tnilkl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149200/original/image-20161208-31385-1tnilkl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149200/original/image-20161208-31385-1tnilkl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149200/original/image-20161208-31385-1tnilkl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149200/original/image-20161208-31385-1tnilkl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pterygium is a benign growth of conjunctival tissue on the cornea.</span>
<span class="attribution"><a class="source" href="https://upload.wikimedia.org/wikipedia/commons/3/34/Pterygium_Slitlamp.jpg">Wikimedia Commons</a></span>
</figcaption>
</figure>
<p><strong>Macular degeneration</strong></p>
<p>This is <a href="https://www.ncbi.nlm.nih.gov/pubmed/21617534">a degenerative disease</a> affecting the central part of the retina (the macula) responsible for central vision. <a href="https://theconversation.com/explainer-what-is-age-related-macular-degeneration-59889">Macular degeneration</a> may result in severe visual impairment. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The macula allows you to see fine detail.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>Treatment comprises injections of medications directly into the eye and aims to limit disease progression; it cannot reverse damage that has already occurred.</p>
<p>While the link between UV exposure and macular degeneration is less clear than with cataracts or pterygia, short-wavelength radiation and blue light (present in bright sunshine) cause damage to the retina. There is a correlation between <a href="https://www.ncbi.nlm.nih.gov/pubmed/21646979">light exposure and macular degeneration</a>. </p>
<p>Wearing sunglasses is therefore important to limit excessive light exposure of the retina.</p>
<p><strong>Cancer</strong></p>
<p>Although less common, chronic UV exposure is associated with increased rates of certain types of eye cancers. These are: <a href="https://www.ncbi.nlm.nih.gov/pubmed/9037556">squamous cell carcinoma of the conjunctiva</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/4033707">melanoma within the eye</a>, and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1771324/">skin cancers of the eyelid</a> and around the eye where people do not routinely apply sunscreen. </p>
<p>Treatment of these cancers may sometimes require surgical removal of the entire eye.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149193/original/image-20161208-31379-nvwhzy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149193/original/image-20161208-31379-nvwhzy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149193/original/image-20161208-31379-nvwhzy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149193/original/image-20161208-31379-nvwhzy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149193/original/image-20161208-31379-nvwhzy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149193/original/image-20161208-31379-nvwhzy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149193/original/image-20161208-31379-nvwhzy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149193/original/image-20161208-31379-nvwhzy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chronic UV exposure is associated with increased rates of certain types of eye cancers.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p><strong>Climatic droplet keratopathy</strong></p>
<p>This is a <a href="https://www.ncbi.nlm.nih.gov/pubmed/1549808">rare disease</a> caused by UV exposure in which the cornea becomes cloudy, obstructing vision and potentially requiring a corneal transplant to restore vision.</p>
<h2>What kind of sunglasses should I wear?</h2>
<p>All sunglasses sold in Australia are regulated under the <a href="http://wiki.cancer.org.au/policy/Position_statement_-_Eye_protection">Australian/New Zealand Standard</a> for sunglasses and fashion spectacles, which assigns a category from zero to four for each pair of sunglasses. </p>
<p>Categories zero and one aren’t sunglasses and so aren’t considered adequate for UV protection. Categories two to four provide effective UV protection and increasing levels of sun glare reduction (although category four must not be worn when driving). </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/149203/original/image-20161208-31379-13hz56e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/149203/original/image-20161208-31379-13hz56e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/149203/original/image-20161208-31379-13hz56e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/149203/original/image-20161208-31379-13hz56e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/149203/original/image-20161208-31379-13hz56e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/149203/original/image-20161208-31379-13hz56e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/149203/original/image-20161208-31379-13hz56e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/149203/original/image-20161208-31379-13hz56e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">More than 90% of UV rays can penetrate through cloud.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/justinwkern/11591028305/in/photolist-iEg3TB-iEheG8-gD1AQf-hyCy9T-afqDfo-eaRir-8wU6hW-aLLcyX-Bp6cz-bPoF8r-5jPra-6Qi17A-6QhZzy-iEmX1H-iEgJ1K-iEicEt-dt5LsA-4z5AY2-pfbjTe-9LE1CS-iEsZsq-fp8Mp6-roCJtM-iEt4FW-i1HNB2-iEi1xD-iEoHjQ-iEipFc-iEp1rs-jfSy1-9R3pm-a5pQyF-8RqbFc-ctJx5W-hdrRGw-27Mot8-8VJP1N-curced-iEsTim-iEhteZ-iEkGBz-iEqBS5-i1GWi8-iEubDS-c2HhJu-hKW4WM-iEj842-kqxNeu-i1GUs4-dVn7JV">Justin Kern/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>It’s important to note price is not an indicator of effectiveness in UV protection. Effective sunglasses should be close-fitting and wrap-around to minimise the amount of UV radiation that can reach the eye.</p>
<p>Some contact lenses also contain UV filters. However, as they cover only the cornea, they provide no protection against the development of pterygia or cancers on or around the eye. </p>
<h2>When should I wear them?</h2>
<p>Sunglasses should be worn at all times when outdoors during the day when the <a href="http://www.bom.gov.au/uv/index.shtml">UV index is 3 or above</a> as there is no defined “safe level” of eye exposure to UV radiation. </p>
<p>They should also be worn regardless of cloudiness, as more than <a href="http://www.unep.org/pdf/Solar_Index_Guide.pdf">90% of UV rays can penetrate through cloud</a>. UV rays also reflect off sand, water and snow. The daily peak period of UV exposure is between 10am and 2pm; seeking shade during these hours is preferable.</p>
<p>The eyes of children are particularly <a href="https://www.ncbi.nlm.nih.gov/pubmed/11227927">susceptible to UV radiation</a>, so children should be encouraged to wear sunglasses as soon as they can tolerate them.</p><img src="https://counter.theconversation.com/content/68582/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jason Yosar does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Whether cheap or expensive, sunglasses play a crucial role in eye protection against ultraviolet radiation.Jason Yosar, Associate Lecturer, School of Medicine, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/598892016-08-10T00:24:33Z2016-08-10T00:24:33ZExplainer: what is age-related macular degeneration?<figure><img src="https://images.theconversation.com/files/130178/original/image-20160712-9292-1gsz5ls.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">In some people AMD progresses so slowly that people do not notice the change in their vision.</span> <span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1457706924510-773f3c796de3?ixlib=rb-0.3.5&q=80&fm=jpg&crop=entropy&s=a577e1cee35179131ae189f5ed25ae15">Ken Wu/Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Age-related macular degeneration (AMD) is the main cause of blindness in Australia. One <a href="http://www.mdfoundation.com.au/LatestNews/MDFoundationDeloitteAccessEconomicsReport%202011ExecSummary.pdf">in seven people</a> aged over 50 have some signs of macular degeneration.</p>
<p>You are reading this article because of your macula, which is the part of the eye affected by macular degeneration. The macula is the central part of the retina or back of the eye that allows you to see fine detail.</p>
<p>In some people, macular degeneration progresses so slowly they don’t notice the change in their vision. In others, the disease progresses faster leading to vision loss in one or both eyes. </p>
<p>The substantial visual impairment linked with age-related macular degeneration means patients have reduced ability to engage in everyday activities, such as reading and driving. </p>
<p>This can result in major disability and be a burden to the person and <a href="https://www.mja.com.au/journal/2006/184/9/modifiable-risk-factors-age-related-macular-degeneration?0=ip_login_no_cache%3D54465b09d6befaee39439148b5e46059">the health care</a> system.</p>
<h2>Forms and causes</h2>
<p>Age-related macular degeneration has two forms: wet and dry. Dry is the most frequent and leads to gradual loss of vision. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/130182/original/image-20160712-9271-11exi8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/130182/original/image-20160712-9271-11exi8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/130182/original/image-20160712-9271-11exi8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/130182/original/image-20160712-9271-11exi8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/130182/original/image-20160712-9271-11exi8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/130182/original/image-20160712-9271-11exi8q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/130182/original/image-20160712-9271-11exi8q.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/130182/original/image-20160712-9271-11exi8q.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Small whitish-yellow blobs of fat and protein called drusen on the macula is an early sign of macular degeneration.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/communityeyehealth/15765705300/in/photolist-czUqTm-7t9FpY-spNxPQ-dRHCyW-q2amVb-uYgohk">Community Eye Health/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>The most common early sign of dry macular degeneration is the presence of small whitish-yellow blobs of fat and protein called drusen on the macula. </p>
<p>These naturally occur as part of the ageing process and are <a href="http://www.aao.org/eye-health/diseases/drusen-causes">believed to be the result</a> of the eye’s failure to eliminate waste products in the cells of the eye.</p>
<p>In the early stages, drusen are small and few and don’t affect vision. But as these blobs become larger, most people report reduction in their central vision.</p>
<p>The wet form of age-related macular degeneration is <a href="http://www.sciencedirect.com/science/article/pii/S0161642006009985">responsible for most of the condition’s severe visual loss</a> but is much less common. It is caused by the growth of abnormal blood vessels that leak and scar underneath the retina. Both the wet and dry forms are painless.</p>
<p>It is currently unclear exactly what causes the processes that lead to macular degeneration, which can make it difficult to prevent. </p>
<p>Age is the strongest known risk factor and the disease is more likely to occur after 50, although it can occur earlier. Cases of macular degeneration have been seen in people in their thirties but this is uncommon.</p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/130187/original/image-20160712-9302-127na3r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The macula is why you’re reading this article.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>There is also such a thing as <a href="http://www.aao.org/eye-health/diseases/juvenile-macular-degeneration">juvenile macular degeneration</a>, which is a series of inherited eye disorders affecting children and young adults – but this is considered different to the age-related form.</p>
<p>A <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4066589/">family history of macular degeneration</a> can increase the risk of getting the disorder by 50%. Studies have shown macular degeneration is <a href="http://archopht.jamanetwork.com/article.aspx?articleid=264670">more common in women</a> than men as well as in people of <a href="http://archopht.jamanetwork.com/article.aspx?articleid=420320">Caucasian and Chinese</a> ethnicity than other ethnic groups.</p>
<p>Smoking is another known risk factor. <a href="http://www.sciencedirect.com/science/article/pii/S0161642000005807">Studies have demonstrated smokers</a> have up to three or four times the risk of getting macular degeneration than non-smokers. </p>
<h2>Symptoms and diagnosis</h2>
<p>The main <a href="http://www.mdfoundation.com.au/symptoms.aspx">symptom of age-related macular degeneration</a> is visual distortion: straight lines appear wavy or bent. People with AMD may also experience difficulty in activities that require fine vision, such as reading or recognising faces. </p>
<p>People with macular degeneration can develop dark patches or blind spots in the centre of their vision. </p>
<p>Symptoms of dry macular degeneration can take five to ten years to become severe. Wet AMD, however, can develop more quickly leading to severe visual loss. </p>
<p>Macular degeneration can be diagnosed by an ophthalmologist who may recommend the Amsler grid test. This is when a special piece of paper with horizontal and vertical lines is used to check visual fields. If any section of the lines is missing or distorted, macular degeneration is a possible cause. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/130188/original/image-20160712-9267-gtoefc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/130188/original/image-20160712-9267-gtoefc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/130188/original/image-20160712-9267-gtoefc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/130188/original/image-20160712-9267-gtoefc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/130188/original/image-20160712-9267-gtoefc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/130188/original/image-20160712-9267-gtoefc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1130&fit=crop&dpr=1 754w, https://images.theconversation.com/files/130188/original/image-20160712-9267-gtoefc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1130&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/130188/original/image-20160712-9267-gtoefc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1130&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">If any section of the lines is missing or distorted, macular degeneration is a possible cause.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>The ophthalmologist will then examine the back of the eye with a slit lamp (a high-intensity light source) microscope and take digital photographs of the retina. </p>
<p>A non-invasive test called ocular coherence tomography uses light waves to scan the retina. It can give a detailed 3D-picture of the macula and show if there are any abnormalities. </p>
<h2>Treatment and prognosis</h2>
<p>There is currently no cure for macular degeneration but treatments are now available for the wet form. These are aimed at maintaining vision for as long as possible and preventing progression of the disease. </p>
<p>The <a href="https://nei.nih.gov/health/maculardegen/armd_facts">main treatment</a> for wet age-related macular degeneration is anti-vascular endothelial growth factor (anti-VEGF) medication. This medication blocks the VEGF, a protein that stimulates blood vessel growth, and prevents the growth of new abnormal blood vessels in the retina. </p>
<p>In some patients, laser surgery can also be used to destroy abnormal blood vessels. Early detection and treatment of wet AMD is vital to reduce the risk of severe vision loss and possibly blindness. </p>
<p>Treatment for dry macular degeneration aims to maintain the best vision for as long as possible. Some ophthalmologists recommend antioxidant supplements to minimise progression – particularly zinc, vitamins C and E and beta carotene.</p>
<p>Quitting smoking can also prevent or slow the progression of dry macular degeneration. A balanced diet of adequate fish intake and dark leafy green vegetables and fruits is recommended. </p>
<p>You can also reduce the risk of age-related macular degeneration by protecting your eyes; wearing sunglasses that have lenses that block and absorb UV rays when outside for long periods of time.</p><img src="https://counter.theconversation.com/content/59889/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bamini Gopinath receives funding from Macular Disease Foundation Australia. </span></em></p>Macular degeneration affects the part of the eye that allows you to see fine detail. Age-related macular degeneration is the main cause of blindness in Australia.Bamini Gopinath, Principal Research Fellow, Sensory Loss Epidemiology, Westmead Institute, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/592952016-06-13T13:23:48Z2016-06-13T13:23:48ZAfrica needs a sustainable solution to deal with cataract blindness<figure><img src="https://images.theconversation.com/files/123195/original/image-20160519-30571-14czm00.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">HelpMeSee</span></span></figcaption></figure><p>Each year in the United States more than three million people undergo procedures to remove a cataract. A cataract is a medical condition where the eye’s natural lens which lies behind the iris and the pupil is clouded. It is the principal cause of blindness in the world. </p>
<p>In the US, most people only experience mild visual impairment before they seek care. Insurance companies or medical aids almost always cover the cost of surgery, which amounts to a total of several thousand dollars per eye. For older patients, especially those over 60, the process is a standard – even expected – procedure.</p>
<p>But for patients in the developing world, the facts could not be more different. 90% of the estimated 20 million people blinded by untreated cataracts live in lower income areas where they lack access to care. </p>
<p>In some <a href="http://www.icoph.org/ophthalmologists-worldwide.html">parts of Africa</a>, such as Chad, Niger, Gabon, Central African Republic and Equatorial Guinea, there are fewer than 10 ophthalmologists for the entire population. France and many European countries, in contrast, have about 50 times that figure. </p>
<p>Cataract surgery is a two part procedure. First patients must be screened to determine if they need surgery. Then, if necessary, the surgery can be performed. Africa lacks both these resources. </p>
<p>The shortage of surgeons extends to Asia and some parts of Latin America. It results in millions of people going blind from a condition for which a cure exists.</p>
<h2>Why cataract blindness is a problem</h2>
<p>There are <a href="http://www.who.int/blindness/GLOBALDATAFINALforweb.pdf?ua=1">more cases of cataracts worldwide</a> than there are of
other eye conditions such as <a href="http://www.glaucoma.org/glaucoma/">glaucoma</a> where the optic nerve in the eye is damaged; <a href="https://www.macular.org/what-macular-degeneration">macular degeneration</a>, when parts of the retina deteriorate; and <a href="http://www.mayoclinic.org/diseases-conditions/diabetic-retinopathy/basics/definition/con-20023311">diabetic retinopathy</a>, which is a diabetes complication that affects eyes – combined. </p>
<p>Cataract blindness continues to affect tens of millions for two main reasons. The first is the lack of access to care. When there is only one certified cataract surgeon in a country with several million people, there is no way all patients can receive the care they need. </p>
<p>In places where there are more surgeons, clinics often focus their care on those people who live in larger cities. As a result, patients from less-developed rural areas are even less likely to receive care than those living in the cities. When these patients do hear about the surgery, they often cannot afford to travel to hospitals that may be hours or even days away. In Africa, there are on average 2.7 surgeons for every million people. </p>
<p>Compare that to the US, where there are over <a href="http://www.icoph.org/ophthalmologists-worldwide.html">58 surgeons</a> for every million people.</p>
<p>The second reason is poverty, both in terms of awareness and financial resources. Many patients in need of cataract surgery –- especially those in remote communities –- do not even know that the care exists. Those that do simply cannot afford it. </p>
<p>The <a href="http://www.who.int/features/factfiles/vision/05_en.html">World Health Organisation</a> cites cataract surgery among the most cost-effective health interventions. But if patients cannot afford it or find assistance, they will never receive care.</p>
<h2>Cheaper treatment expands access</h2>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/123384/original/image-20160520-4484-yp3yef.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/123384/original/image-20160520-4484-yp3yef.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/123384/original/image-20160520-4484-yp3yef.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/123384/original/image-20160520-4484-yp3yef.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/123384/original/image-20160520-4484-yp3yef.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/123384/original/image-20160520-4484-yp3yef.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/123384/original/image-20160520-4484-yp3yef.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Dr Jean-Marie André, HelpMeSee’s medical officer for Africa, observes a manual small incision cataract surgery in Banjul, The Gambia.</span>
<span class="attribution"><span class="source">HelpMeSee</span></span>
</figcaption>
</figure>
<p>Our work at <a href="http://helpmesee.org/">HelpMeSee</a>, a non-governmental organisation, is to train cataract specialists within their communities to solve this problem.</p>
<p>Treatment exists in the form of a cost-effective, high quality procedure called Manual Small Incision Cataract Surgery. This involves a self-sealing incision, which is what allows this sutureless surgery to be so efficient.</p>
<p>It costs significantly less than <a href="http://www.surgeryencyclopedia.com/Pa-St/Phacoemulsification-for-Cataracts.html">phacoemulsification</a>, which is the standard in the US and requires an ultra-sound machine that needs expensive maintenance. </p>
<p>The small incision surgery delivers very similar results to the phacoemulsification. Surgeons familiar with other procedures can be taught the small incision surgery in two to three months.</p>
<p>There are two examples where our training has worked well. In The Gambia in West Africa, HelpMeSee identified more than 5 700 people in need of care. This is less than 1% of the population. But working with the country’s leading eye hospital, we expanded capacity for screening and surgical delivery. </p>
<p>With its smaller geography and population of about two million, we adopted a similar approach in The Gambia to what we achieved in districts in India which had about the same population size. We focused on a set geographic region, identified all those who were blind because of cataracts and connected them to the care they deserve. Once this phase is complete, the focus shifted to providing sustainable community care.</p>
<p>In Madagascar, where nearly 100 000 people – or less than 1% – are blind because of cataracts, our approach includes both health care policy at the government level and nationwide partnerships. </p>
<h2>The need to improve access to care</h2>
<p>The public health crisis of cataract blindness has not received the same coverage or awareness as malaria or polio. It should. Cataracts as a health issue will not go away. But cataract blindness can, if access to care is expanded to all those in need. Only a significant expansion in the number of specialists providing care will ensure that no one needlessly goes blind.</p>
<p>For the tens of millions who remain blind from untreated cataracts, a brief procedure to restore sight can return lost hope and opportunity.</p><img src="https://counter.theconversation.com/content/59295/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jean-Marie Andre is the Africa Medical Officer for HelpMeSee, a donor funded global non profit organisation that runs a global campaign to eliminate blindness caused by untreated cataract. </span></em></p>Cataract blindness continues to affects tens of millions of people because they cannot access proper care.Jean-Marie Andre, Ophthalmologist at the School of Medicine, Aix-Marseille Université (AMU)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/475342015-09-23T04:29:05Z2015-09-23T04:29:05ZExplainer: South Africa’s challenges in the search for genes causing eye disease<figure><img src="https://images.theconversation.com/files/95684/original/image-20150922-16679-vu3k9q.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A visually impaired young girl reads a Braille notice. Retinal dysfunction results in one in 3 500 people suffering night blindness, loss of peripheral vision and later complete blindness.</span> <span class="attribution"><span class="source">Reuters/Amr Abdallah Dalsh </span></span></figcaption></figure><p>The retina is a thin, light-sensitive tissue at the back of the eye. It captures light and converts it into a chemical signal which travels to the brain, ultimately registering as vision. The retina is actually part of the central nervous system and is considered part of the brain. The ‘photoreceptors’ or light-sensitive nerve cells of the retina, are divided into the rod cells and the cone cells, reflecting their actual shapes. </p>
<p>There are about 120 million rod cells spread throughout the retina. These are responsible for black and white vision, and allow vision in low-light conditions. Then the six million cone cells are located in the centre of the retina, in an area called the macula, and are responsible for colour vision and detailed central vision.</p>
<p>A group of diseases collectively called inherited retinal degenerative <a href="http://www.humangenetics.uct.ac.za/wp-content/uploads/2013/02/Fact-Sheet-8-Inherited-RD.pdf">disorders</a> are caused by genetic defects which cause vision loss. This may result in total blindness. These disorders are caused by genetic changes or mutations and are inherited within families. </p>
<p>These genetic mutations result in different disorders. Gene defects affecting mainly the rod photoreceptors cause retinitis pigmentosa. As a result patients experience night blindness and loss of peripheral vision, causing a tunnel-like vision. Genetic mutations causing a primary loss of cone photoreceptors result in <a href="http://www.humangenetics.uct.ac.za/wp-content/uploads/2013/02/Fact-Sheet-6-Stargardt-Dystrophy.pdf">Stargardt disease</a> or macular degeneration and cause a loss of central vision.</p>
<h2>A rare disease without a cure</h2>
<p>Although genetic diseases are generally rare, globally about 1 in 3500 people suffer from retinal degenerative disorders. In South Africa and Africa, exact statistics around retinal degenerative disorders are not available. We estimate that at least 14 500 South Africans suffer from vision loss because of these disorders. This conservative estimate is based on reported retinal degenerative disorders cases but each disorder has a different incidence rate so this number is likely higher.</p>
<p>There is currently no cure for retinal degenerative disorders but many gene therapies for these diseases are being established. In gene therapy the mutation in a gene has been corrected and is inserted into a patient’s cells as a treatment for disease. </p>
<p>There are at least eight clinical trials across the globe in countries such as the US. These trials are testing the safety and efficacy of gene therapies in patients with these disorders.</p>
<h2>Advances in treatment</h2>
<p>The use of gene therapy for <a href="http://www.nih.gov/researchmatters/june2013/06242013eye.htm">eye diseases</a> are further advanced than for most other diseases. This is because the eye is small, easily accessible and self-contained. This means small amounts of treatment with the corrected gene can be inserted directly where needed. </p>
<p>There is little worry about unwanted off-target effects - where other sites in the genome are unintentionally modified - because the treatment does not cross the blood-brain barrier and cannot enter the rest of the body. This is the biggest concern within the gene therapy field.</p>
<p>But to participate in any of these trials, the patient must have a confirmed genetic diagnosis, meaning a confirmed mutation in the gene which is to be replaced or repaired.</p>
<p>The genetic cause of these disorders must be identified in South Africans for the clinical trials to come to the country - a process that <a href="http://www.retinasa.org.za/">Retina South Africa</a> has been intricately involved in. </p>
<h2>Complicated genetics in retinal dysfunction</h2>
<p>There are several challenges in identifying the genes causing retinal degenerative disorders in families. </p>
<p>The first is that the genetics of these disorders are complex. There are more than 280 genes reported to be linked to these disorders. Mutations in any one of those genes can cause these disorders. There are potentially hundreds of mutations in each gene. Some genes are obvious candidates involved in the cells or biological pathways required for vision. Others are unlikely culprits and are responsible for normal functioning of cells in the body. They cause no other disease besides retinal dysfunction and subsequent vision loss. </p>
<p>Secondly, retinal degenerative disorders can be inherited in families in different ways. They can also manifest as part of a syndrome such as <a href="http://www.humangenetics.uct.ac.za/wp-content/uploads/2013/02/Fact-Sheet-5-Usher-Syndrome.pdf">Usher syndrome</a>, which involves both vision impairment and hearing loss. </p>
<p>An ophthalmologist cannot tell from a clinical examination what the genetic cause of the disorder is. Patients with different mutated genes can end up with the same clinical disease. For example, more than 55 different genes can each cause retinis pigmentosa. What further complicates this is within families, people with the same genetic mutation can have different symptoms.</p>
<p>And as the disease progresses over time the symptoms change, which can result in a change of the disease diagnosis. </p>
<p>Making a genetic diagnosis is challenging and requires detailed clinical information and family history. But having a genetic diagnosis is essential to participate in any gene therapy based clinical trials.</p>
<h2>The South African challenge</h2>
<p>Finding a genetic diagnosis is also complicated by the unique genetic diversity of Africans. Most white South Africans originated from European settlers so our testing for the specific genetic mutations reported internationally has been successful over the last 26 years of research at the University of <a href="http://www.humangenetics.uct.ac.za/">Cape Town</a>. </p>
<p>But there is less success with this approach for black South Africans. African populations have vast genetic diversity, as a result of admixture between populations and migration around, out of and back into Africa. </p>
<p>Our current research with Professor Anand Swaroop at the National Eye <a href="https://nei.nih.gov">Institute</a> in the US uses the next generation of DNA sequencing technology to sequence the entire coding region of the human genome, known as the exome, in black South Africans. </p>
<p>The exome is the one to two percent of the human genome containing active portions of all 20 000 known human genes. By sequencing the exome of this unique patient population group, we hope to identify their genetic basis of retinal degenerative diseases, which may have relevance to the continent as a whole. </p>
<p>This is a new technology and local scientists require collaboration and training in the analysis, as well as major computational resources. It is an approach which does not rely purely on our existing knowledge of retinal degenerative disorder genes but includes all human genes, both likely and unlikely candidates.</p><img src="https://counter.theconversation.com/content/47534/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Funding for this research project is provided by the University of Cape Town, the Medical Research
Council of South Africa and the lay support society Retina South Africa.</span></em></p>Today is the start of World Retinal Week. Establishing retinal degenerative disorders in Africa is challenged by the unique genetic diversity of Africans.Lisa Roberts, Medical Biological Scientist: Scientific Officer and Project Leader of the Retinal Degenerative Disorders research group, Division of Human Genetics, UCT, University of Cape TownLicensed as Creative Commons – attribution, no derivatives.