tag:theconversation.com,2011:/us/topics/opthalmology-30662/articlesOpthalmology – The Conversation2023-05-12T12:19:21Ztag:theconversation.com,2011:article/2005262023-05-12T12:19:21Z2023-05-12T12:19:21ZGene therapy helps combat some forms of blindness – and ongoing clinical trials are looking to extend these treatments to other diseases<figure><img src="https://images.theconversation.com/files/517754/original/file-20230327-14-rcucem.jpg?ixlib=rb-1.1.0&rect=24%2C18%2C997%2C490&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">New gene therapies are helping to treat certain forms of inherited blindness.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/view-of-a-blind-man-assisted-by-a-friend-as-he-walks-on-a-news-photo/1299277661?phrase=blind%20person%20walking&adppopup=true">GettyImages</a></span></figcaption></figure><p><em><a href="https://www.orbis.org/en/news/2021/new-global-blindness-data#">An estimated 295 million people</a> suffer from visual impairment globally. Around 43 million of those people are living with blindness. While not every form of blindness can be cured, <a href="https://pubmed.ncbi.nlm.nih.gov/33278565/">recent scientific breakthroughs</a> have uncovered new ways to treat some forms of inherited blindness through gene therapy.</em></p>
<p><em><a href="https://www.med.upenn.edu/apps/faculty/index.php/g275/p11214">Jean Bennett</a> is a gene therapy expert and a professor emeritus of ophthalmology at the University of Pennsylvania. She and her laboratory developed the first gene therapy drug for a genetic disease to be approved in the U.S. The drug, <a href="https://luxturna.com/">Luxturna</a>, treats patients with biallelic RPE65 mutation-associated retinal dystrophy, a rare genetic disorder that causes visual impairments and blindness in patients early in life.</em></p>
<p><em>In March, Bennett spoke at the 2023 <a href="https://www.imaginesolutionsconference.com/">Imagine Solutions Conference</a> in Naples, Florida, about what gene therapy is, why it matters and the success she and her team have had helping the blind to see. The Conversation caught up with Bennett after the conference. Her edited answers are below.</em></p>
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<figcaption><span class="caption">Jean Bennett speaks at the 2023 Imagine Solutions Conference.</span></figcaption>
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<h2>What is gene therapy and how does it work?</h2>
<p><a href="https://www.fda.gov/vaccines-blood-biologics/cellular-gene-therapy-products/what-gene-therapy">Gene therapy</a> is a set of techniques that harness <a href="https://medlineplus.gov/genetics/understanding/basics/dna/">DNA</a> or <a href="https://www.umassmed.edu/rti/biology/what-is-rna/">RNA</a> to treat or prevent disease. Gene therapy treats disease in <a href="https://www.childrenshospital.org/treatments/gene-therapy#">three primary ways</a>: by substituting a disease-causing gene with a healthy new or modified copy of that gene; turning genes on or off; and injecting a new or modified gene into the body.</p>
<h2>How has gene therapy changed how doctors treat genetic eye diseases and blindness?</h2>
<p>In the past, many doctors did not think it necessary to identify the genetic basis of eye disease because treatment was not yet available. However, a few specialists, including <a href="https://www.med.upenn.edu/carot/">me and my collaborators</a>, identified these defects in our research, convinced that someday treatment would be made possible. Over time, we were able to create a treatment designed for individuals with particular gene defects that lead to congenital blindness.</p>
<p>This development of gene therapy for inherited disease has <a href="https://www.eye-tuebingen.de/wissingerlab/projects/rd-cure/">inspired</a> <a href="https://atsenatx.com/">other</a> <a href="https://www.medicalnewstoday.com/articles/gene-therapy-for-macular-degeneration">groups</a> around the world to initiate clinical trials targeting other genetic forms of blindness, such as <a href="https://medlineplus.gov/genetics/condition/choroideremia/">choroideremia</a>, <a href="https://medlineplus.gov/genetics/condition/achromatopsia/">achromatopsia</a>, <a href="https://medlineplus.gov/genetics/condition/retinitis-pigmentosa/">retinitis pigmentosa</a> and even <a href="https://www.hopkinsmedicine.org/health/conditions-and-diseases/agerelated-macular-degeneration-amd">age-related macular degeneration</a>, all of which lead to vision loss. There are at least <a href="https://www.clinicaltrials.gov/">40 clinical trials</a> enrolling patients with other genetic forms of blinding disease. </p>
<p>Gene therapy treatments are now available in pharmacies and operating rooms all over the world. </p>
<p>Gene therapy is even being used to restore vision to people whose photoreceptors – the cells in the retina that respond to light – have completely degenerated. This approach uses <a href="https://pubmed.ncbi.nlm.nih.gov/36499371/">optogenetic therapy</a>, which aims to revive those degenerated photoreceptors by adding light-sensing molecules to cells, thereby drastically improving a person’s vision.</p>
<h2>You created one of the first gene therapies approved in the US. What is the current state of the clinical use of gene therapy?</h2>
<p>There are now many approved gene therapies in the U.S., but the majority are combined with cell therapies in which a cell is modified in a dish and then injected back into the patient. </p>
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<img alt="Woman in lab coat, face mask, goggles and gloves squeezes syringe into petri dish" src="https://images.theconversation.com/files/512977/original/file-20230301-1750-ujq9ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/512977/original/file-20230301-1750-ujq9ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/512977/original/file-20230301-1750-ujq9ka.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/512977/original/file-20230301-1750-ujq9ka.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/512977/original/file-20230301-1750-ujq9ka.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/512977/original/file-20230301-1750-ujq9ka.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/512977/original/file-20230301-1750-ujq9ka.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">Many forms of gene therapy are helping to treat blindness.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/asian-female-doctor-is-working-in-laboratory-royalty-free-image/1363580438?phrase=laboratory%20technician&adppopup=true">GettyImages</a></span>
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<p>The majority of those therapies target different forms of cancer, although there are several for devastating inherited diseases. The drug <a href="https://www.fda.gov/vaccines-blood-biologics/skysona">Skysona</a> is a new injectable gene therapy medication that treats boys ages 4 to 17 with <a href="https://www.childrenshospital.org/conditions/adrenoleukodystrophy-ald">cerebral adrenoleukodystrophy</a>, a genetic disease in which a buildup of very-long-chain fatty acids in the brain can lead to death.</p>
<p>The gene therapy that my team and I developed was the first FDA-approved project involving injection of a gene therapy directly into a person – in this case, into the retina. Only one other <a href="https://www.fda.gov/vaccines-blood-biologics/zolgensma">FDA-approved gene therapy</a> is directly administered to the body – one that targets <a href="https://www.hopkinsmedicine.org/health/conditions-and-diseases/spinal-muscular-atrophy-sma#">spinal muscular atrophy</a>, a disease that causes progressive muscle weakness and eventually death. The drug, Zolgensma, is injected intravenously into babies and children diagnosed with the disease, allowing them to live as healthy, active children. </p>
<p>There are now more than two dozen FDA-approved cell and gene therapies, including <a href="https://theconversation.com/anti-cancer-car-t-therapy-reengineers-t-cells-to-kill-tumors-and-researchers-are-expanding-the-limited-types-of-cancer-it-can-target-196471">CAR T-cell therapies</a> – in which T cells, a type of immune system cells, are modified in the laboratory to better attack cancer cells in the body – and therapies for various blood diseases.</p>
<h2>What are you currently working on that you’re most excited about?</h2>
<p>I am very excited about some <a href="https://clinicaltrials.gov/ct2/show/NCT05616793?cond=LCA5&draw=2&rank=1">upcoming clinical trials</a> that my team will soon initiate to target some other devastating blinding diseases. We will incorporate a new test of functional vision – how your eyes, brain and the visual pathways between them work together to help a person move in the world. This test utilizes a virtual reality game that is not only fun for the user but promises to provide an objective measure of the person’s functional vision. I hope that our virtual reality test will inform us of any potential benefits from the treatments and also serve as a useful outcome measure for other gene and cell therapy clinical trials involving vision.</p>
<h2>What are the biggest challenges gene therapy faces?</h2>
<p>The biggest challenges involve systemic diseases, or diseases affecting the entire body rather than a single organ or body part. For those diseases, super-high doses of gene therapy reagents must be delivered. Such diseases involve not only technical challenges – such as how to manufacture enormous amounts of gene therapy compounds without contaminating them – but also difficulties ensuring that the treatment targets diseased tissues without causing toxic immune side effects. That level of a problem does not exist with the eye, where relatively small doses are used and exposure to the rest of the body is limited.</p>
<p>Another challenge is how to address diseases in which the target gene is very large. Current approaches to delivering treatments into cells lack the capacity to hold large genes.</p>
<p>Cost remains a key issue in this effort – gene therapy drugs are <a href="https://www.nytimes.com/2017/09/11/health/cost-gene-therapy-drugs.html">enormously expensive</a>. As drug manufacturers are able to refine this technique, gene therapy drugs may become more commonplace, causing their price to drop as a result.</p><img src="https://counter.theconversation.com/content/200526/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jean Bennett was a founder of GenSight Biologics and Opus Genetics and was a scientific (non-equity holding) founder of Spark Therapeutics. She and her husband waived any potential financial gain from Luxturna in 2002 so that they could conduct the clinical trials. Her team received funds from the Children's Hospital of Philadelphia, Foundation Fighting Blindness and Spark Therapeutics to run those trials. She is a co-author on a number of gene therapy patents, including one on LCA5 gene therapy that was licensed to Opus Genetics. She also is a co-author of intellectual property relating to use of virtual reality for vision assessment. She also serves on Scientific Advisory Boards for several groups and serves on Boards of two companies (Opus Genetics and REGENXBIO) and a private Foundations (RDFund).</span></em></p>Genetics expert Jean Bennett explains how gene therapy is being used to treat certain forms of inherited blindness.Jean Bennett, Professor Emeritus of Ophthalmology; Cell and Developmental Biology, University of PennsylvaniaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1984932023-02-15T18:52:40Z2023-02-15T18:52:40ZOntario’s private surgical clinics: Cheques but no balances when providing health care<figure><img src="https://images.theconversation.com/files/510199/original/file-20230214-26-1i76q6.jpg?ixlib=rb-1.1.0&rect=0%2C482%2C4801%2C2584&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ontario's push to for-profit surgical clinics is bad news for the non-profit public health-care system.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/ontario-s-private-surgical-clinics--cheques-but-no-balances-when-providing-health-care" width="100%" height="400"></iframe>
<p><a href="https://www.cbc.ca/news/canada/toronto/ford-jones-health-surgeries-private-clinics-1.6715117">Private surgical clinics</a> are one proposal to tackle surgical backlogs and wait lists. </p>
<p>But are they the right solution?</p>
<p>It’s critical to consider the trade-offs when surgeries are moved out of non-profit facilities, like hospitals and community clinics, and into for-profit clinics.</p>
<p>Ontario’s private eye surgery clinics are an interesting case. They were the <a href="https://www.cbj.ca/bochner_eye_institute/">first in the province</a> to perform surgeries outside hospitals. Some have been around for decades, doing for-profit cosmetic and laser eye surgeries for people who pay directly for procedures. Most are owned by ophthalmologists.</p>
<p>The Ontario government has just approved contracts for three <a href="https://www.theglobeandmail.com/canada/article-doug-ford-announcement-private-surgeries/">laser eye for-profit businesses</a> to do cataract surgeries to be paid for by the province’s public health insurance, known as OHIP. This raises important issues.</p>
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Read more:
<a href="https://theconversation.com/explainer-what-are-cataracts-63699">Explainer: what are cataracts?</a>
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<h2>Unhealthy trade-offs</h2>
<p>Surgeries in for-profit clinics cost the public system more than if the surgeries were performed in non-profit hospitals.</p>
<p>Ontario <a href="https://www.health.gov.on.ca/en/public/programs/ihf/docs/IHF_application_guidelines.pdf">will pay clinics</a> a flat facility fee of $605 per patient for a single-cataract surgery and $1,015 for a double-cataract surgery. </p>
<p>The facility fee is paid by the public system to cover overhead, such as technicians, technology, nurses, supplies and buildings, and is separate from surgeon fees. Any payment exceeding costs is retained as profit by the clinic. </p>
<p>The comparable overhead fee paid to non-profit hospitals is <a href="https://www.theglobeandmail.com/opinion/article-ontario-does-not-need-more-for-profit-surgery/">closer to $500 per patient</a>. Hospitals don’t make a profit, and their funding is allocated to meet patient needs.</p>
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<a href="https://images.theconversation.com/files/509945/original/file-20230214-26-cr4ign.jpg?ixlib=rb-1.1.0&rect=0%2C109%2C4817%2C2962&q=45&auto=format&w=1000&fit=clip"><img alt="A closeup of an eye with a light shining on it." src="https://images.theconversation.com/files/509945/original/file-20230214-26-cr4ign.jpg?ixlib=rb-1.1.0&rect=0%2C109%2C4817%2C2962&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/509945/original/file-20230214-26-cr4ign.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/509945/original/file-20230214-26-cr4ign.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/509945/original/file-20230214-26-cr4ign.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/509945/original/file-20230214-26-cr4ign.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/509945/original/file-20230214-26-cr4ign.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/509945/original/file-20230214-26-cr4ign.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">For-profit clinics in Ontario are performing cataract and other eye surgeries, siphoning money and resources from the public system.</span>
<span class="attribution"><span class="source">(Unsplash)</span></span>
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<p><a href="https://ottawacitizen.com/news/local-news/ottawa-eye-clinic-says-it-has-a-licence-to-perform-5000-additional-cataract-surgeries-per-year-under-provincial-expansion">One clinic</a> has a contract for 5,000 cataract surgeries, yielding more than $3 million in facility fees plus more than $2 million in surgeon’s billings. The facility fee from that single contract is at least $500,000 more than any non-profit hospital would receive. </p>
<p>How could that $500,000 be used for improvements to the health system instead? </p>
<p>Funds are desperately required to hire health-care workers. Maybe the money from that single contract could fund thousands of hours of home care with personal support workers or hire several full-time registered nurses to staff a hospital operating room. </p>
<p>Ontario could also invest more in <a href="https://www.oma.org/uploadedfiles/oma/media/public/hcp-factsheet-doctor-shortage.pdf">primary-care teams to service the estimated two million residents without family doctors</a>. It could open more medical school spots. It could encourage more residency spots for ophthalmology and fund more staff physician positions at teaching hospitals to do their training. </p>
<h2>Eroding the public health system</h2>
<p>If <a href="https://toronto.ctvnews.ca/ontario-releases-3-step-plan-to-invest-in-private-care-to-reduce-surgical-backlog-1.6232067">Ontario’s three-step plan to contract out more for-profit surgical and diagnostic centres</a> happens, significant public funds will be diverted towards profit. This will result in huge costs to the health system. </p>
<p>Contracting out these surgeries isn’t about lack of space. The Ontario auditor general reported there are <a href="https://www.auditor.on.ca/en/content/annualreports/arreports/en21/AR_Outpatient_en21.pdf">under-used surgical spaces in Ontario hospitals</a> that require nursing staff to operate. This is a human resources challenge, not a space challenge. </p>
<p>Ontario only has <a href="https://doi.org/10.1016/j.jcjo.2018.10.022">three ophthalmologists for every 100,000 residents</a>. That ratio is worsened when ophthalmologists work only partially in the public system and spend the rest of their time doing privately paid procedures like laser eye surgeries. Only 68 per cent of Ontario ophthalmologists perform cataract surgeries.</p>
<p>By way of contrast, in Nova Scotia — with <a href="https://www.cihi.ca/sites/default/files/document/national-physician-database-data-release-2020-2021-meth-notes-en.pdf">five ophthalmologists for every 100,000 people</a> — 75 per cent perform cataract surgeries, improving access for Nova Scotians.</p>
<p>Surgical backlogs for medically necessary surgeries, such as cataract removal, are also affected by laser eye and cosmetic surgeries. Every hour doing laser eye surgeries is an hour less for cataract surgery. </p>
<p>The province could regulate how often ophthalmologists perform optional procedures to prioritize medically necessary surgeries that save people’s vision. </p>
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<img alt="A patient lies on a gurney as a doctor performs surgery on their eye." src="https://images.theconversation.com/files/510202/original/file-20230214-20-zb0f6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/510202/original/file-20230214-20-zb0f6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/510202/original/file-20230214-20-zb0f6h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/510202/original/file-20230214-20-zb0f6h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/510202/original/file-20230214-20-zb0f6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/510202/original/file-20230214-20-zb0f6h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/510202/original/file-20230214-20-zb0f6h.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">Every hour doing laser eye surgeries is an hour less for a cataract surgery.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
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<h2>Balances needed for the public system</h2>
<p><a href="https://www.cosprc.ca/wp-content/uploads/2022/09/COS-Principles.pdf">The Canadian Ophthalmological Society</a> has advocated against profit as a main professional motivation. Allowing physicians to have a foot in both public and for-profit medicine causes surgical backlogs for everyone.</p>
<p>Ontario should require the profession to recommit to the public system — because the public system has committed to ophthalmologists. Like other trained physicians in Canada, ophthalmologists are significantly underwritten by public funds for part of their medical tuition, to fund the physicians who train them as residents, and for partial coverage of their <a href="https://www.health.gov.on.ca/en/pro/programs/ohip/mlp/default.aspx">medical liability protection</a> insurance. </p>
<p>Cataract surgery is the <a href="https://doi.org/10.1503/cmaj.161140">most common surgery performed across Canada</a>. Medically necessary cataract surgery is needs-based, unlike elective laser eye or cosmetic surgery, and demand is high. The wait lists grow because too few ophthalmologists are performing it. </p>
<p>Between 2011 and 2016, the <a href="https://www.cihi.ca/en/national-physician-database-metadata">number of surgeons performing cataract surgery in Ontario decreased by 44 per cent</a>. The overall number of surgeries performed held steady after 2016, but demand has increased with an aging population and because of pandemic-related backlogs.</p>
<p>To improve wait lists and be transparent with public funds, there must be better accountability on the part of the profession. </p>
<p>Unlike other physician groups, ophthalmologists didn’t participate in the federal <a href="https://choosingwiselycanada.org/">Choosing Wisely campaign</a> to designate unnecessary tests and procedures that are costly to the system.</p>
<p>Ophthalmologists earn more because of a mismatch between the time it takes to perform the surgery and the fee that’s paid. While <a href="https://www.thestar.com/news/investigations/2019/07/04/of-the-194-highest-billing-doctors-in-ontario-54-are-ophthalmologists-why.html">technology has greatly decreased the time required</a>, the fee hasn’t dropped proportionally. </p>
<p>Ophthalmologists bill OHIP $398 for each surgery. Some <a href="http://www.ottawaretina.com/faq.html">bill for dozens of patients per day</a>, higher than in the past because surgeries are performed faster. <a href="https://www.thestar.com/news/investigations/2019/07/04/of-the-194-highest-billing-doctors-in-ontario-54-are-ophthalmologists-why.html">Ophthalmologists are one third in the trinity of top-billing physicians</a> in Ontario. </p>
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<h2>Regulations required</h2>
<p>OHIP covers standard cataract lenses, but ophthalmologists can offer upgraded lenses to eliminate the need for glasses if patients pay additional fees. </p>
<p>These fees aren’t publicized, and there’s room for abuse, so Ontario needs government regulations to oversee any fees paid directly by patients. </p>
<p>Stories abound about <a href="https://www.chathamdailynews.ca/news/local-news/chatham-ophthalmologist-receives-four-month-suspension-also-dinged-10k-for-cost-of-cpso-discipline-hearing">packages</a> billed to patients for lenses not received; about the <a href="https://ottawa.ctvnews.ca/fear-of-upselling-as-some-surgeries-move-to-for-profit-clinics-in-ontario-1.6234733">upselling of lenses</a> that <a href="https://www.thestar.com/politics/provincial/2023/02/05/when-it-comes-to-cataract-surgery-is-there-more-to-ontarios-private-clinics-than-meets-the-eye.html">may not actually benefit patients</a> but play on their fears; and issues <a href="https://www.thestar.com/news/investigations/2019/07/05/a-top-billing-ophthalmologist-charged-ohip-for-doing-an-eye-procedure-more-times-than-all-other-doctors-combined-another-billed-for-128-laser-treatments-in-one-day-the-numbers-have-some-medical-expe.html">with dubious</a> <a href="https://www.stcatharinesstandard.ca/news/crime/2020/03/05/former-niagara-eye-doctor-andrew-taylor-hit-with-fine-repayment-order.html">or fraudulent</a> billing. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1622280145955442689"}"></div></p>
<p>There are also <a href="https://www.theobserver.ca/news/local-news/chatham-ophthalmologist-going-before-cpso-disciplinary-committee-monday/wcm/772f9fe6-b4b0-4689-8336-19bdda22bbb7/amp/">ongoing investigations by the College of Physicians and Surgeons of Ontario</a>. <a href="https://www.thestar.com/news/gta/2019/07/11/a-guide-to-understanding-the-stars-database-of-ontarios-top-billing-doctors.html">Twenty per cent of the top 20 ophthalmologist billers</a> have reportedly recently had their licences restricted or suspended. Currently, the college reviews <a href="https://clinics.cpso.on.ca/">for-profit surgical clinics</a> to maintain medical licences, but some have not been reviewed since 2016. </p>
<p>Ontario’s Health Ministry should conduct a value-for-money audit that could stop the practice of costlier patients, and most of the time-intensive training, remaining in non-profit hospitals as for-profits pursue lower-cost patients. Well-trained personnel may also be attracted to for-profits, where they retain more of their billings. </p>
<p>Unchecked, these practices lead to higher costs for the public system and to some patients jumping queues for surgeries.</p>
<p>Ontario should also change how <a href="https://www.ontariohealth.ca/public-reporting/wait-times">wait times</a> are publicly reported. Patients could select their ophthalmologist and join a single wait list. Instead of publicly reporting wait lists by hospital, they should be publicly reported by ophthalmologist, including how many of their assigned cases are handled according to priority benchmarks. </p>
<p>These are just some of the innovations needed to bring balance to the system.</p><img src="https://counter.theconversation.com/content/198493/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tamara Daly receives funding from SSHRC. </span></em></p>Ontario is significantly expanding the number and range of medical procedures performed in privately run clinics. Here’s why that’s so problematic.Tamara Daly, Professor of Health Policy and Equity, York University, CanadaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1824182022-05-11T19:55:43Z2022-05-11T19:55:43ZOne in three people are infected with ‘Toxoplasma’ parasite – and the clue could be in our eyes<figure><img src="https://images.theconversation.com/files/462178/original/file-20220510-20-i2xe1.jpg?ixlib=rb-1.1.0&rect=26%2C8%2C5964%2C3907&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-illustration/parasitic-protozoans-toxoplasma-gondii-causative-600w-2136137853.jpg">Shutterstock</a></span></figcaption></figure><p><em>Toxoplasma gondii</em> is probably the most successful parasite in the world today. This microscopic creature is capable of infecting any mammal or bird, and people across all continents are <a href="https://pubmed.ncbi.nlm.nih.gov/32717377/">infected</a>. Once infected, a person carries <em>Toxoplasma</em> for life. So far, we don’t have a drug that can eradicate the parasite from the body. And there is no vaccine approved for use in humans.</p>
<p>Across the world, it’s estimated <a href="https://pubmed.ncbi.nlm.nih.gov/22491772/">30–50% of people</a> are infected with <em>Toxoplasma</em> – and infections may be increasing in Australia. A survey of studies conducted at blood banks and pregnancy clinics across the country <a href="https://pubmed.ncbi.nlm.nih.gov/470719/">in the 1970s</a> put the infection rate at 30%. However, a recent Western Australian <a href="https://ro.ecu.edu.au/ecuworkspost2013/8534/">community-based study</a> found 66% of people were infected.</p>
<p>The disease caused by this parasite can scar the back of the eye. Our <a href="https://www.ophthalmologyretina.org/article/S2468-6530(22)00215-9/fulltext">new research</a> looked for signs of disease in otherwise healthy people and found a significant number bore the mark of <em>Toxoplasma</em>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/cats-carry-diseases-that-can-be-deadly-to-humans-and-its-costing-australia-6-billion-every-year-147910">Cats carry diseases that can be deadly to humans, and it's costing Australia $6 billion every year</a>
</strong>
</em>
</p>
<hr>
<h2>We don’t just get it from cats</h2>
<p>The cat is the primary host for <em>Toxoplasma</em>. </p>
<p>Cats catch the parasite when they eat infected prey. Then, for a couple of weeks, they pass large numbers of parasites in their faeces in a form that can survive for long periods in the environment, even during extreme weather. </p>
<p>When the faeces are ingested by livestock while grazing, parasites lodge in the muscle and survive there after the animals are slaughtered for meat. Humans can become infected by eating this meat, or by eating fresh produce or drinking water soiled by cats. It is also possible for a woman infected for the first time during pregnancy to pass the infection to her unborn child.</p>
<p>While infection with <em>Toxoplasma</em> is extremely common, the most important health statistic is the rate of the disease caused by the infection, which is called toxoplasmosis. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/disease-causing-parasites-can-hitch-a-ride-on-plastics-and-potentially-spread-through-the-sea-new-research-suggests-181824">Disease-causing parasites can hitch a ride on plastics and potentially spread through the sea, new research suggests</a>
</strong>
</em>
</p>
<hr>
<h2>How it affects the eye</h2>
<p><em>Toxoplasma</em> <a href="https://pubmed.ncbi.nlm.nih.gov/32717377/">really likes the retina</a>, the multi-layered nerve tissue that lines the eye and generates vision. Infection can cause recurring attacks of retinal inflammation and <a href="https://pubmed.ncbi.nlm.nih.gov/22712598/">permanent retinal scarring</a>. This is known as ocular toxoplasmosis.</p>
<p>Contrary to much that is written about ocular toxoplasmosis, medical research shows this condition usually <a href="https://pubmed.ncbi.nlm.nih.gov/16226526/">affects healthy adults</a>. However, in aged persons or people with a weakened immune system, or when contracted during pregnancy, it can be more severe.</p>
<p>An attack of active inflammation causes “floaters” and blurred vision. When the inflammation progresses to scarring, there may be permanent loss of vision. </p>
<p>In a <a href="https://www.nature.com/articles/s41598-021-82830-z">study</a> of patients with ocular toxoplasmosis seen at a large ophthalmology clinic, we measured reduced vision to below driving level in more than 50% of eyes, and 25% of eyes were irreversibly blind.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/462169/original/file-20220510-17-mu0okv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="close up of person's eye" src="https://images.theconversation.com/files/462169/original/file-20220510-17-mu0okv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462169/original/file-20220510-17-mu0okv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462169/original/file-20220510-17-mu0okv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462169/original/file-20220510-17-mu0okv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462169/original/file-20220510-17-mu0okv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462169/original/file-20220510-17-mu0okv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462169/original/file-20220510-17-mu0okv.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"><em>Toxoplasma</em> really likes the retina at the back of the eye and can leave a scar.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/flagged/photo-1552065172-4f7d73c31fca?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxzZWFyY2h8MTB8fHJldGluYSUyMGV5ZXxlbnwwfHwwfHw%3D&auto=format&fit=crop&w=800&q=60">Unsplash/Marc Schulte</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>How many eyes?</h2>
<p>Ophthalmologists and optometrists are quite familiar with managing ocular toxoplasmosis. But the extent of the problem is not widely recognised, even by the medical community. The number of Australians with ocular toxoplasmosis had never been measured, until now.</p>
<p>We wanted to investigate the prevalence of ocular toxoplasmosis in Australia, but we knew it would be challenging to get funding for a major survey of this neglected disease. So, we used information collected for a different purpose: as part of the Busselton Healthy Ageing Study, retinal photographs were taken from more than 5,000 baby boomers (born 1946–64) living in Busselton, Western Australia. The photographs <a href="https://bmcpublichealth.biomedcentral.com/articles/10.1186/1471-2458-13-936">were gathered</a> to look for other eye diseases, macular degeneration and glaucoma.</p>
<p>By screening these retinal photographs, we <a href="https://www.ophthalmologyretina.org/article/S2468-6530(22)00215-9/fulltext">estimated</a> the prevalence of ocular toxoplasmosis at one in 150 Australians. This might seem surprisingly common, but it fits with the way people catch <em>Toxoplasma</em>. </p>
<p>In addition to pet cats, Australia has huge populations of <a href="https://pubmed.ncbi.nlm.nih.gov/32547918/">feral cats</a>. And Australia is home to a lot of farmland, including over 50% of the <a href="https://www.researchgate.net/publication/329231876_Maps_of_Organic_Agriculture_in_Australia">global organic farming area</a>. </p>
<p>Most importantly, many Australians like to eat their <a href="https://bright-r.com.au/how-most-australians-prefer-their-steak-cooked/#:%7E:text=Research%20conducted%20by%20Brighter%20has,Australians%20prefer%20a%20medium%20steak.">red meat rare</a>, putting them at real risk. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/462171/original/file-20220510-24-li5uy5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="cute cat rolls on back" src="https://images.theconversation.com/files/462171/original/file-20220510-24-li5uy5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462171/original/file-20220510-24-li5uy5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462171/original/file-20220510-24-li5uy5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462171/original/file-20220510-24-li5uy5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462171/original/file-20220510-24-li5uy5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462171/original/file-20220510-24-li5uy5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462171/original/file-20220510-24-li5uy5.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"></a>
<figcaption>
<span class="caption">Yes, cats do spread <em>Toxoplasma</em>. But they’re not solely to blame.</span>
<span class="attribution"><a class="source" href="https://unsplash.com/photos/46TvM-BVrRI">Unsplash/Daria Shatova</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ive-always-wondered-can-i-flush-cat-poo-down-the-toilet-159340">I've always wondered: can I flush cat poo down the toilet?</a>
</strong>
</em>
</p>
<hr>
<h2>How the condition is treated</h2>
<p>To diagnose ocular toxoplasmosis, a retina examination is necessary, ideally with the pupils dilated. </p>
<p>The retinal lesion is easy to spot, because of the way <em>Toxoplasma</em> <a href="https://pubmed.ncbi.nlm.nih.gov/31569536/">activates retinal cells</a> to produce certain proteins, and an ophthalmologist or optometrist can immediately recognise the appearance. Often a blood test is also performed to make the diagnosis.</p>
<p>If the condition is mild, the doctor may let the body’s own immune system control the problem, which takes a few months. However, <a href="https://pubmed.ncbi.nlm.nih.gov/35197262/">usually</a> a combination of anti-inflammatory and anti-parasitic drugs is prescribed. </p>
<h2>Stopping the spread</h2>
<p><em>Toxoplasma</em> infection is not curable, but it can be prevented. Meat sold in Australian supermarkets <a href="https://pubmed.ncbi.nlm.nih.gov/31825558/">may harbour</a> <em>Toxoplasma</em>__. Cooking meat to an internal temperature of <a href="https://www.cdc.gov/parasites/toxoplasmosis/prevent.html">66°C</a> or freezing it ahead of cooking are ways to <a href="https://www.taylorfrancis.com/books/mono/10.1201/9781420092370/toxoplasmosis-animals-humans-dubey">kill the parasite</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/462177/original/file-20220510-15-xpot89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="raw steak on a plate" src="https://images.theconversation.com/files/462177/original/file-20220510-15-xpot89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/462177/original/file-20220510-15-xpot89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=359&fit=crop&dpr=1 600w, https://images.theconversation.com/files/462177/original/file-20220510-15-xpot89.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=359&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/462177/original/file-20220510-15-xpot89.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=359&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/462177/original/file-20220510-15-xpot89.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=451&fit=crop&dpr=1 754w, https://images.theconversation.com/files/462177/original/file-20220510-15-xpot89.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=451&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/462177/original/file-20220510-15-xpot89.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=451&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Meat needs to be well-cooked to 66°C to kill the parasite.</span>
<span class="attribution"><a class="source" href="https://images.unsplash.com/photo-1638294133684-b2036f3ecd76?ixlib=rb-1.2.1&ixid=MnwxMjA3fDB8MHxwaG90by1wYWdlfHx8fGVufDB8fHx8&auto=format&fit=crop&w=3371&q=80">Unsplash</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Fresh fruit and vegetables should be washed before eating, and drinking untreated water (such as straight from rivers or creeks) should be avoided. Gloves should be worn when changing cat litter, and hands washed afterwards.</p>
<p>The World Health Organization and other international and national health bodies are promoting an approach called <a href="https://www.who.int/news-room/questions-and-answers/item/one-health">One Health</a> for diseases that cross humans, animals and their environments. This involves different sectors working together to promote good health. Now we know just how common ocular toxoplasmosis is in Australia, there is real justification to harness One Health to combat <em>Toxoplasma</em> infections in this country.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/a-dangerous-parasite-could-be-used-to-treat-cancer-new-research-in-mice-171022">A dangerous parasite could be used to treat cancer – new research in mice</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/182418/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Justine R. Smith receives funding from NHMRC, Macular Disease Foundation Australia, Australian Department of Industry, Science, Energy and Resources, Flinders Foundation, QEI Foundation and South Bank Day Hospital.</span></em></p><p class="fine-print"><em><span>João M. Furtado 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>We looked at eye photos and found one in every 150 Australians might have scarring from a common parasitic disease.Justine R. Smith, Professor of Eye & Vision Health, Flinders UniversityJoão M. Furtado, Associate Professor of Ophthalmology, Universidade de São Paulo (USP)Licensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1718262021-11-25T04:21:36Z2021-11-25T04:21:36ZWhat is orthokeratology? And will it help slow the deterioration of my child’s eyesight?<figure><img src="https://images.theconversation.com/files/432109/original/file-20211116-21-1fbmxqn.jpg?ixlib=rb-1.1.0&rect=0%2C7%2C2443%2C1616&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>If you or your child is short-sighted (struggles to see things further away) you might have heard about orthokeratology. </p>
<p>Also known as OK or ortho-k, orthokeratology has been around since the 1960s. However, it has gained interest recently for its ability to slow the progression of myopia (short-sightedness).</p>
<p>Orthokeratology involves wearing a specially-designed rigid contact lens overnight. Like a mold, the lens temporarily reshapes the eye while you sleep by gently changing the profile of the cornea (the eye’s clear, protective outer layer that acts like a powerful lens).</p>
<p>This creates a temporary change; when you wake up, you take the lens off and voilà! You can see.</p>
<p>It takes about a week of going through the cycle for the full effect to be reached but after that – assuming you wear them every night and take them off every morning – you should be able to get through your days without glasses or contact lenses. </p>
<p>And most importantly, there’s good evidence it can help slow the progression of myopia.</p>
<p>Like all treatments, however, orthokeratology has its pros and cons – and its risks need to be well understood before use. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/hidden-in-plain-sight-how-the-covid-19-pandemic-is-damaging-childrens-vision-158737">Hidden in plain sight: How the COVID-19 pandemic is damaging children’s vision</a>
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</em>
</p>
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<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432114/original/file-20211116-25-1tk03qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/432114/original/file-20211116-25-1tk03qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432114/original/file-20211116-25-1tk03qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432114/original/file-20211116-25-1tk03qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432114/original/file-20211116-25-1tk03qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432114/original/file-20211116-25-1tk03qz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432114/original/file-20211116-25-1tk03qz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432114/original/file-20211116-25-1tk03qz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&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 orthokeratology lens temporarily reshapes the eye while you sleep.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>The pros</h2>
<p>Orthokeratology may be an appealing option:</p>
<ul>
<li><p>for people who want an alternative to glasses but find contact lenses either uncomfortable or not suitable (because, for example, they suffer from <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/dry-eye">dry eye</a>, work in dusty environments or enjoy water sports)</p></li>
<li><p>as an alternative to refractive surgery, also known as laser eye surgery or LASIK. Refractive surgery is permanent but orthokeratology is temporary; if you stop using the lenses, things go back to normal within a week</p></li>
<li><p>for parents of a child who might otherwise be wearing contact lenses at school; ortho-k allows a child to go to school without glasses or contact lenses, which can be lost or come loose during the day.</p></li>
</ul>
<h2>The cons</h2>
<p>The potential downsides include:</p>
<ul>
<li><p>the up-front costs are higher than daily wear contact lenses where the similar overall cost is spread over time</p></li>
<li><p>the effect wears off if you don’t use them every night</p></li>
<li><p>all contact lens use comes with a higher risk of eye infection than if you had no contact lenses at all.</p></li>
</ul>
<p>Some people might think orthokeratology has a higher infection risk than standard soft contact lenses. However, this is not supported by the research evidence. </p>
<p>A <a href="https://onlinelibrary.wiley.com/doi/10.1111/opo.12460">study in Japan</a> compared outcomes after 10 years of wear in children of either orthokeratology or soft contact lenses. It found there were no severe adverse events and the frequency of mild and adverse events were about equal between the groups. </p>
<p>If you get an infection from either a standard contact lens or orthokeratology lenses, it usually clears up with a course of antibiotics. However, it’s possible to get a rare infection called microbial keratitis, which has the potential to damage sight.</p>
<p>It’s not common. According to one <a href="https://journals.lww.com/optvissci/Abstract/2013/09000/The_Risk_of_Microbial_Keratitis_With_Overnight.6.aspx">study</a>, if you were to wear an orthokeratology lens every night for 1,000 years you are only likely to get one serious infection. </p>
<p>If you use sterile contact lens solutions and avoid tap water, orthokeratology lens-wearers will dramatically reduce their risk of eye infection. Tap water exposure to lenses or lens accessories greatly <a href="https://iovs.arvojournals.org/article.aspx?articleid=2124094">increases the risk of infection</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432111/original/file-20211116-25-1fqf1ts.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A girl gets her eyes tested." src="https://images.theconversation.com/files/432111/original/file-20211116-25-1fqf1ts.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432111/original/file-20211116-25-1fqf1ts.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432111/original/file-20211116-25-1fqf1ts.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432111/original/file-20211116-25-1fqf1ts.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432111/original/file-20211116-25-1fqf1ts.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432111/original/file-20211116-25-1fqf1ts.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432111/original/file-20211116-25-1fqf1ts.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">Slower myopia progression also means less frequent need for replacing glasses, which can save you money in the long run.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Reducing risk of devasting eye disease later in life</h2>
<p>It’s now projected <a href="https://www.aaojournal.org/article/S0161-6420(16)00025-7/fulltext">half the world’s population will by myopic by 2050</a>, and the World Health Organization has sounded the alarm, saying in one <a href="https://www.who.int/bulletin/volumes/98/6/19-240903.pdf">bulletin</a>:</p>
<blockquote>
<p>High myopia greatly increases the risk of macular atrophy, glaucoma and
other causes of severe vision loss, the incidence of which is not reduced by
wearing standard glasses.</p>
</blockquote>
<p>Slowing the progression of myopia reduces <a href="https://theconversation.com/hidden-in-plain-sight-how-the-covid-19-pandemic-is-damaging-childrens-vision-158737">risk of sight-threatening eye disease</a>. It also means less frequent changes in vision, which can save money in the long run from needing fewer changes to glasses.</p>
<p>Myopia progresses <a href="https://journals.lww.com/optvissci/Abstract/2012/01000/Myopia_Progression_Rates_in_Urban_Children_Wearing.7.aspx">faster in younger years</a>, so a myopia control prevention should be prescribed as early as possible. We don’t know exactly how orthokeratology slows myopia progression, but compelling <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0124535">research</a> shows it does.</p>
<p>If you’re considering orthokeratology for your child, you and your eye specialist need to strike a balance. The child must be old enough to be handle it – but wait too long and the the myopia control benefits it offers diminish. </p>
<p>Every child is different. Some are more able than others to contend with orthokeratology, or willing to wear it overnight. It can be uncomfortable at first, and some might find the idea of a contact lens too confronting. It cannot be forced.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/432113/original/file-20211116-13-1j6celv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/432113/original/file-20211116-13-1j6celv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/432113/original/file-20211116-13-1j6celv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/432113/original/file-20211116-13-1j6celv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/432113/original/file-20211116-13-1j6celv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/432113/original/file-20211116-13-1j6celv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/432113/original/file-20211116-13-1j6celv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/432113/original/file-20211116-13-1j6celv.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">Too much ‘close work’ can make myopia worse in children.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Review all the options</h2>
<p>Orthokeratology isn’t the only solution; there are also special lenses you can get for glasses and soft daily wear contact lenses that help slow progression of myopia. Seek advice from eye specialists to to review all the options. </p>
<p>I also recommend children do no more than two hours per day of leisure “close work” (meaning non-school work: close up screen time or book-reading) outside school hours. Parents can also teach kids the “<a href="https://www.mykidsvision.org/blog/the-visual-environment/">20-20 rule</a>” (for every 20 minutes of close work, take a 20 second break to look into the distance). Outside time (<a href="https://www.mdpi.com/1660-4601/16/14/2595">two or more hours per day</a>) is also crucial to healthy eye development in children.</p>
<p>What’s clear, however, is that all short-sighted children should be doing something to control their myopia. It’s not enough just to give a child standard single vision glasses to help them see, without doing more to help slow the march of myopia.</p>
<p>If right for your child, orthokeratology has one of the strongest research pedigrees for slowing progression of myopia.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-keep-your-contact-lenses-clean-and-what-can-go-wrong-if-you-dont-141117">How to keep your contact lenses clean (and what can go wrong if you don't)</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/171826/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Gifford is an Adjunct Senior Lecturer at the University of New South Wales and Adjunct Associate Professor at the University of Waterloo, Canada. He is co-founder of Myopia Profile, which educates optometrists and companies on research relating to vision, and MyKidsVision.org which provides parent focused research backed information on managing childhood myopia.</span></em></p>Orthokeratology involves wearing a specially designed rigid contact lens overnight. There’s good evidence it can help slow the progression of myopia. But like all treatments, there are risks, too.Paul Gifford, Adjunct Senior Lecturer, UNSW SydneyLicensed 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">
<figcaption>
<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>
<hr>
<p>
<em>
<strong>
À lire aussi :
<a href="https://theconversation.com/glaucoma-visions-silent-killer-113878">Glaucoma: Vision's silent killer</a>
</strong>
</em>
</p>
<hr>
<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/1543782021-02-05T03:59:12Z2021-02-05T03:59:12ZCurious Kids: why do we see different colours when we close our eyes?<figure><img src="https://images.theconversation.com/files/382652/original/file-20210205-16-minmco.png?ixlib=rb-1.1.0&rect=0%2C0%2C1207%2C847&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://pixabay.com/vectors/stained-glass-window-design-3519999/">Prettysleepy1/Pixabay</a></span></figcaption></figure><p><strong>Why do we see different colours when we close our eyes? — Anais, aged 7</strong></p>
<p><a href="https://theconversation.com/au/topics/curious-kids-36782"><img src="https://images.theconversation.com/files/291898/original/file-20190911-190031-enlxbk.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=90&fit=crop&dpr=1" width="100%"></a></p>
<p>Hi Anais, thanks for your great question! </p>
<p>The first thing to say is that seeing colours when we close our eyes is totally normal. It doesn’t mean there’s a problem with your eyes (unless what you see changes drastically, but we’ll talk about that later).</p>
<p>There are a few different situations that can cause you to see colours with your eyes closed. The first one is if you shut your eyes in the daytime, in a bright room or outside. Some light does go through your closed eyelids. So you might see a dark reddish colour because the <a href="https://www.sciencedirect.com/science/article/abs/pii/S0161642094312127">lids</a> have lots of blood vessels in them and this is the light taking on the colour of the blood it passes through.</p>
<p>But often we see different colours and patterns when we close our eyes in the dark. </p>
<p>I certainly do! When I first shut my eyes in the dark, I see a pattern that’s full of dots and sparkles. Then when I’m in the dark for a longer time, I see swirls and waves of coloured dots travelling through my vision.</p>
<p>I know what I’m seeing is not made by something real, because it’s always changing and seems very random.</p>
<figure class="align-center ">
<img alt="An artistic depiction of phosphenes" src="https://images.theconversation.com/files/382657/original/file-20210205-18-1dd9j3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382657/original/file-20210205-18-1dd9j3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=325&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382657/original/file-20210205-18-1dd9j3g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=325&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382657/original/file-20210205-18-1dd9j3g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=325&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382657/original/file-20210205-18-1dd9j3g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=409&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382657/original/file-20210205-18-1dd9j3g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=409&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382657/original/file-20210205-18-1dd9j3g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=409&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An artistic depiction of the patterns and colours we sometimes see at night.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Phosphene_artistic_depiction_image_color.jpg">Al2/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>You can also see these with your eyes open, particularly when you’ve been in the dark for a while, maybe when you have woken up in the middle of the night (if there isn’t too much stray light coming in from the window or elsewhere). </p>
<p>These perceptions are what scientists call “<a href="https://pubmed.ncbi.nlm.nih.gov/26544101/">phosphenes</a>” — the sensation of light that’s not actually caused by light. They can start in the eye or the brain, but the ones you are talking about are usually due to the normal functioning of the retina. The retina is the layer that lines the inside of the back of your eye that detects light.</p>
<h2>Why does it happen?</h2>
<p>These phosphenes are a normal part of how our eyes work. Our eyes don’t turn off in the dark, but instead they create very weak <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0148336">internal signals that mimic light</a>.</p>
<p><a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0148336">These signals</a> are constantly being made by the cells at the back of your eyes.</p>
<p>The swirls and waves we see are made by changes in activity from these cells. The blobs may be coloured because the cells in your eyes that detect colour also show this activity.</p>
<p>These signals are transmitted to the brain, and the brain interprets this random activity. Your brain doesn’t know they weren’t produced by real light, so we think we’re seeing coloured lights and patterns that are not there. It’s a kind of illusion!</p>
<h2>And what about when you rub your eyes?</h2>
<p>You might also see colours when you <a href="https://dukeeyecenter.duke.edu/news-events/whats-really-happening-when-we-see-stars-after-rubbing-our-eyes">rub your eyes</a>. This is because pushing (softly!) on your eyeballs causes physical force to be applied to the light detectors at the back of your eyes. This force can then create the phosphenes we’ve spoken about. You might see a dark circle surrounded by a ring of light where you have pushed on your eye.</p>
<p>Some people notice flashes of light when they move their eyes quickly, particularly if they’ve gotten up in the middle of the night in a dark room. As we get older, the clear jelly in the back section of the eye gets more watery. This fluid can move around a bit when the eye is moved quickly. It can tug on your eyes’ light detectors and causes you to see <a href="https://jamanetwork.com/journals/jamaophthalmology/article-abstract/625190">a flash of light</a>.</p>
<figure class="align-center ">
<img alt="Young girl covering her eyes outside" src="https://images.theconversation.com/files/382656/original/file-20210205-22-1xp1jh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/382656/original/file-20210205-22-1xp1jh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=433&fit=crop&dpr=1 600w, https://images.theconversation.com/files/382656/original/file-20210205-22-1xp1jh9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=433&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/382656/original/file-20210205-22-1xp1jh9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=433&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/382656/original/file-20210205-22-1xp1jh9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=544&fit=crop&dpr=1 754w, https://images.theconversation.com/files/382656/original/file-20210205-22-1xp1jh9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=544&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/382656/original/file-20210205-22-1xp1jh9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=544&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">You might notice different colours when you’re gently rubbing your eyes. This is caused by the extra pressure on the cells that detect light.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>Is there something wrong with us?</h2>
<p>Seeing colours when you close your eyes is totally normal. It’s just part of the way your eyes work. Some people notice them, and some do not.</p>
<p>However, much more obvious phosphenes can occur in some <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2189731/">eye diseases</a>.</p>
<p>If what you’re seeing has changed, and the patterns of light become much more noticeable or hang around for longer, it could indicate a problem.</p>
<p>For example, bright flashing can be caused by a detached retina, which is where your retina partially comes away from the back of your eyeball, and which needs to be treated as an emergency. </p>
<p>Also, some people get a “visual aura” when they have a particular kind of headache called a migraine. High pressure inside your eyeballs can also cause phosphenes.</p>
<p>If what you’re seeing has drastically changed, or you’re worried about what you’re seeing, it’s best to visit your eye care provider, a doctor or an optometrist. </p>
<hr>
<p><em>Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to curiouskids@theconversation.edu.au</em></p><img src="https://counter.theconversation.com/content/154378/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katrina Schmid works for the School of Optometry and Vision Science, Queensland University of Technology</span></em></p>It’s a sensation of light that isn’t caused by real light. And don’t worry, it’s totally normal.Katrina Schmid, Associate Professor, Queensland University of TechnologyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1435232020-09-07T11:36:15Z2020-09-07T11:36:15ZThere’s no evidence that blue-light blocking glasses help with sleep<figure><img src="https://images.theconversation.com/files/352569/original/file-20200812-24-1i2zvox.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C6000%2C3997&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There is a lack of good clinical research on the advantages of blue-light filtering lenses. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>Health products, like detox teas and <a href="https://www.healthline.com/nutrition/detox-water-101">mood-boosting waters</a>, rely on a lack of neuroscientific knowledge to make their claims. Some of these claims are unsubstantiated, while others are completely made up.</p>
<p>My doctoral research investigates visual processing, but when I look at the big picture, I realize that what I’m really studying are fundamental aspects of brain anatomy, connectivity and communication. </p>
<p>One specific function of the visual system that I have studied during my degree is the blue-light detecting molecule, <a href="https://doi.org/10.1016/j.tins.2007.11.002">melanopsin</a>. In humans, melanopsin is seemingly restricted to a group of neurons in the eye, which preferentially target a structure in the brain called the suprachiasmatic nucleus — the body’s clock. </p>
<h2>Circadian rhythms</h2>
<p>This is where the (true) idea that blue light affects our sleep-wake cycle or circadian rhythm originates from. And also why many corrective lens producers have started cashing in on blue-light filtering glasses. The most common claims that go along with these lenses is that <a href="https://time.com/5752454/blue-light-sleep/">they will help restore our natural sleep-wake cycle</a>.</p>
<p>Blue-filtering lenses are marketed as a solution to so many other vision problems. There are claims that they <a href="https://www.cbc.ca/news/canada/marketplace-blue-light-lenses-hidden-camera-investigation-1.5364678">protect against a retinal disease called macular degeneration, decrease headaches and ward off eye cancer</a>.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/NkJY9bgLyBE?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A CBC Marketplace investigation into blue-light lenses.</span></figcaption>
</figure>
<h2>Blue-light complexity</h2>
<p>Ophthalmologists generally agree that there is “<a href="https://doi.org/10.1111/opo.12414">a current lack of high-quality clinical evidence to support a beneficial effect with blue‐blocking spectacle lenses for reducing eye fatigue, enhancing sleep quality or preserving macular health in the general population</a>.” </p>
<p>Similar to the workings of any biological system, melanopsin’s contribution to vision is more complicated than it is made out to be. </p>
<p>For example, melanopsin — like other light-sensitive molecules in our eyes — can result in neural activity outside of blue light specifically. Blue is simply where it is most sensitive. So, then, blue light does indeed affect our sleep-wake cycle, but so will other wavelengths of light, to a lesser extent. </p>
<p>But what is the real culprit of the effects of digital screen light on our sleep-wake cycle? Is it necessarily blue light alone or is the problem likely worsened by people commonly staying up late and using their devices? </p>
<p>The science seems to be on the <a href="https://doi.org/10.1111/opo.12406">side that is against any substantial effects of blue-light blocking lenses</a>. If you are staying up late anyway, blue-light blocking lenses aren’t proven to provide any help.</p>
<p>Research has shown that one likely cause for eye irritation and fatigue is the time we spend in front of our screens overall, which may <a href="https://doi.org/10.1097/opx.0000000000000157">decrease the amount of blinking we do</a>. </p>
<figure class="align-center ">
<img alt="Fatigued woman using laptop at night" src="https://images.theconversation.com/files/352571/original/file-20200812-24-ee9ria.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/352571/original/file-20200812-24-ee9ria.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/352571/original/file-20200812-24-ee9ria.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/352571/original/file-20200812-24-ee9ria.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/352571/original/file-20200812-24-ee9ria.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/352571/original/file-20200812-24-ee9ria.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/352571/original/file-20200812-24-ee9ria.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 amount of time we spend looking at screens — especially late at night — contributes to eye irritation and fatigue.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Filling the gap in clinical research</h2>
<p>The problem seems to be not only blue-light filtering lens sellers, but the way in which we talk about findings from research. </p>
<p>As of yet, there is no clinical evidence that supports the benefits of using blue-light filtering lenses. For now, this is another pseudoscience market that’s taken advantage of its consumer base — anyone who uses computers.</p>
<p>Expanding neuroscience literacy should be a public health goal: understanding how the brain and its partner organs — like the eye — work.</p>
<p>For now, keeping our eyes off screens at night and taking frequent breaks from screens is what will contribute most to our eye health and sleep hygiene.</p><img src="https://counter.theconversation.com/content/143523/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tareq Yousef receives funding from the Dalhousie University Department of Ophthalmology and Visual Sciences and has previously received funding from the Dalhousie University Faculty of Medicine and the Nova Scotia Health Research Foundation.</span></em></p>Some health products haven’t been tested for the benefits that they claim to produce. Blue-light blocking lenses are promoted as helping sleep cycles, but there is no evidence to support this.Tareq Yousef, PhD candidate, Medical Neuroscience, Dalhousie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1072162018-12-05T15:13:12Z2018-12-05T15:13:12ZWhy Victorians feared modern technology would make everyone blind<figure><img src="https://images.theconversation.com/files/248998/original/file-20181205-186076-caliv1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Examination by ophthalmoscope in JF Phillips' Ophthalmic Surgery and Treatment, 1869.</span> <span class="attribution"><a class="source" href="https://wellcomelibrary.org/item/b21072280#?c=0&m=0&s=0&cv=509&z=-0.2641%2C-0.1021%2C1.7312%2C1.2445">Wellcome Library </a></span></figcaption></figure><p>From concerns over <a href="https://www.thisisinsider.com/do-blue-light-blocking-glasses-work-2018-11">blue light</a> to <a href="https://www.bustle.com/p/are-smartphones-making-our-eyes-worse-heres-how-to-protect-yourself-according-to-experts-9179808">digital strain</a> and <a href="https://www.nhs.uk/news/lifestyle-and-exercise/office-screen-work-linked-to-dry-eye-syndrome/">dryness</a>, headlines today often worry how smartphones and computer screens might be affecting the health of our eyes. But while the technology may be new, this concern certainly isn’t. Since Victorian times people have been concerned about how new innovations might damage eyesight. </p>
<p>In the 1800s, the rise of mass print was both blamed for an increase in eye problems and was responsible for dramatising the fallibility of vision too. As the amount of known eye problems increased, the Victorians predicted that without appropriate care and attention Britain’s population would become blind. In 1884, an article in The Morning Post newspaper proposed that: </p>
<blockquote>
<p>The culture of the eyes and efforts to improve the faculty of seeing must become matters of attentive consideration and practice, unless the deterioration is to continue and future generations are to grope about the world purblind. </p>
</blockquote>
<p>The 19th century was the time when opthamology <a href="http://fs.aoa.org/optometry-archives/optometry-timeline.html">became a more prominent field</a> of healthcare. New diagnostic technologies, <a href="https://www.college-optometrists.org/the-college/museum/online-exhibitions/virtual-ophthalmic-instrument-gallery/test-charts.html">such as test charts</a> were introduced and spectacles became a <a href="http://blog.wellcomelibrary.org/2016/08/what-did-the-victorians-make-of-spectacles/">more viable treatment method</a> for a range of vision errors. But though more sight problems were being treated effectively, this very increase created alarm, and a subsequent perceived need to curtail any growth. </p>
<p>In 1889 the Illustrated London News questioned: </p>
<blockquote>
<p>To what are we coming? … Now we are informed by men of science that the eyes used so effectively by our forefathers will not suffice for us, and that there is a prospect of England becoming purblind.</p>
</blockquote>
<p>The article continued, considering potential causes for this acceleration, and concluded that it could be partly explained by evolution and inheritance. </p>
<h2>Urban myopia</h2>
<p>Other commentators looked to “modern life” for explanation, and attributed the so-called “deterioration of vision” to the built environment, the rise of print, compulsory education, and a range of new innovations such as steam power. In 1892, an article, published in The Nineteenth Century: A Monthly Review, reflected that the changing space of Victorian towns and lighting conditions were an “inestimable benefit” that needed to be set against a “decidedly lower sight average”. Similarly, a number of other newspapers reported on this phenomenon, headlining it as “urban myopia”.</p>
<p>In 1898, a feature published in The Scottish Review – ironically entitled “The Vaunts of Modern Progress” – proposed that defective eyesight was “exclusively the consequence of the present conditions of civilised life”. It highlighted that many advances being discussed in the context of “progress” – including material prosperity, expansion of industry and the rise of commerce – had a detrimental effect on the body’s nervous system and visual health. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/248997/original/file-20181205-186052-hmkbow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/248997/original/file-20181205-186052-hmkbow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/248997/original/file-20181205-186052-hmkbow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=376&fit=crop&dpr=1 600w, https://images.theconversation.com/files/248997/original/file-20181205-186052-hmkbow.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=376&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/248997/original/file-20181205-186052-hmkbow.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=376&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/248997/original/file-20181205-186052-hmkbow.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=473&fit=crop&dpr=1 754w, https://images.theconversation.com/files/248997/original/file-20181205-186052-hmkbow.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=473&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/248997/original/file-20181205-186052-hmkbow.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=473&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Reading advice from JD Browning’s 1887 book Our Eyes and How to Preserve Them from Infancy to Old Age.</span>
<span class="attribution"><a class="source" href="https://wellcomelibrary.org/item/b20392473#?c=0&m=0&s=0&cv=0&z=-0.6516%2C-0.0828%2C2.303%2C1.6556">Wellcome Library</a></span>
</figcaption>
</figure>
<p>Another concern of the time – <a href="https://www.joh.cam.ac.uk/early-19th-century-guide-getting-fitness-spirit">sedentariness</a> – was also linked to the rise in eye problems. Better transport links and new leisure activities that <a href="https://theconversation.com/anthropocene-why-the-chair-should-be-the-symbol-for-our-sedentary-age-105319">required the person to be seated</a> meant people had more time to read. Work changed as well, with lower-class jobs moving away from manual labour and the written word thought to have superseded the spoken one. While we now focus on “screen time”, newspapers and periodicals emphasised the negative effects of a “reading age” (the spread of the book and popular print).</p>
<h2>Education to blame</h2>
<p><a href="https://www.thetimes.co.uk/article/bad-news-pupils-studying-damages-eyesight-mnsd8vh09">In a similar manner to today</a>, schools were blamed for the problem too. Reading materials, lighting conditions, desk space, and the advent of compulsory education were all linked to the rise in diagnosed conditions. English ophthalmologist Robert Brudenell Carter, in his government-led study, Eyesight in Schools, reached the balanced conclusion that while schooling conditions may be a problem, more statistics were required to fully assess the situation. Though Carter did not wish to “play the part of an alarmist”, a number of periodicals dramatised their coverage with phrases such as “The Evils of Our School System”. </p>
<p>The problem with all of these new environmental conditions was that they were considered “artificial”. To emphasise this point, medical men frequently compared their findings of poor eye health against the superior vision of “savages” and the effect of captivity on the vision of animals. This in turn gave a more negative interpretation of the relationship between civilisation and “progress”, and conclusions were used to support the idea that deteriorating vision was an accompaniment of the urban environment and modern leisure pursuits – specific characteristics of the Western world. </p>
<p>And yet the Victorians were undeterred, and continued with the very modern progress that they blamed for eyesight problems. Instead, <a href="https://www.college-optometrists.org/the-college/museum/online-exhibitions/virtual-spectacles-gallery/nineteenth-century-spectacles.html">new protective eyewear was developed</a> that sought to protect the eye from dust and flying particles, as well as from the bright lights at seaside resorts, and artificial lighting in the home.</p>
<p>Despite their fears, the country did not become “purblind”. Neither is Britain now an “island full of round-backed, blear-eyed book worms” as predicted. While stories reported today tend to rely on more rigorous research when it comes to screen time and eye health, it just goes to show that “modernity” has long been a cause for concern.</p><img src="https://counter.theconversation.com/content/107216/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Gemma Almond has received AHRC funding for this research as part of her collaborative doctoral award at Swansea University and the Science Museum. </span></em></p>Screen time wasn’t a issue in the 19th century but that didn’t stop concerns over how new developments might damage eyesightGemma Almond, PhD Researcher, Swansea UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/636992016-09-19T19:58:27Z2016-09-19T19:58:27ZExplainer: what are cataracts?<figure><img src="https://images.theconversation.com/files/135769/original/image-20160829-17859-bvfh20.png?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><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>Nearly <a href="http://www.aihw.gov.au/media-release-detail/?id=6442464587">one-third of Australians</a> aged 55 or over (or around 1.5 million people) have an untreated cataract. In 2013-14, there were <a href="http://www.aihw.gov.au/eye-health/cataract-surgery/">229,693 hospital admissions</a> for cataract surgeries, making cataracts one of the most prevalent conditions among Australians. </p>
<p>Cataracts remain one of the <a href="http://www.who.int/mediacentre/factsheets/fs282/en/">leading causes</a> of visual impairment globally; they are responsible for blindness in <a href="http://www.who.int/blindness/causes/priority/en/index1.html">20 million people</a> worldwide.</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>
<h2>What is a cataract?</h2>
<p>The word cataract comes from the Latin <em>cataracta</em>, which means waterfall. It is a clouding of the normally transparent crystalline lens in the eye. </p>
<p>The lens works together with the cornea to focus light onto the retina, which converts light to electrical signals that are transferred to the brain. This gives us the images we see.</p>
<p>Cataracts commonly cause blurring of vision, glare from bright lights – especially oncoming vehicle headlights – halos around lights, loss of colour saturation and poorer night vision. Affected people may notice they <a href="http://eyebulletin.com/what-is-second-sight-and-how-does-it-happen/">no longer need their reading glasses</a> as a cataract causes a paradoxical increase in the focusing power of the lens.</p>
<p>Because cataracts develop slowly and painlessly, they may progress for many years before being diagnosed. If left untreated, however, they may eventually cause severe visual impairment in the affected eye. Cataracts commonly occur in both eyes but may occur in one eye alone, or <a href="http://www.optometry.org.au/your-eyes/your-eye-health/eye-diseases/cataract.aspx#cat4">progress at different rates in each eye</a>.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/135596/original/image-20160826-17865-1a0rmb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/135596/original/image-20160826-17865-1a0rmb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=589&fit=crop&dpr=1 600w, https://images.theconversation.com/files/135596/original/image-20160826-17865-1a0rmb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=589&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/135596/original/image-20160826-17865-1a0rmb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=589&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/135596/original/image-20160826-17865-1a0rmb3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=740&fit=crop&dpr=1 754w, https://images.theconversation.com/files/135596/original/image-20160826-17865-1a0rmb3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=740&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/135596/original/image-20160826-17865-1a0rmb3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=740&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">If left untreated, cataracts may eventually cause severe visual impairment in the affected eye.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<h2>What causes cataracts?</h2>
<p>Cataract formation is part of the normal ageing process of the lens. More than <a href="https://www.health.gov.au/internet/main/publishing.nsf/Content/D1A5409787D800F2CA257C73007F12F3/$File/eyehlth.pdf">70% of men and women</a> aged 80 and above will have a cataract.</p>
<p>The most common type of cataract is age-related, which is thought to occur due to breakdown and degradation of lens proteins over time. <a href="https://www.ncbi.nlm.nih.gov/pubmed?term=7725232">This process can be accelerated</a> by smoking, chronic diseases, such as diabetes and high blood pressure, and exposure to ultraviolet light and radiation.</p>
<p>Less commonly, cataracts can occur following <a href="https://www.ncbi.nlm.nih.gov/pubmed?term=16107513">prolonged use of steroid medications</a>, such as those taken for rheumatoid arthritis and other chronic inflammatory conditions. They can also occur following <a href="http://emedicine.medscape.com/article/1211083-overview">trauma or radiation to the eye</a>.</p>
<p>A very small number – around 2.2 per 10,000 babies <a href="http://bjo.bmj.com/content/86/7/782.full">in one Australian study</a> – are born with congenital cataracts. These usually occur on their own or uncommonly in association with other diseases, such as rubella infection.</p>
<h2>How are cataracts treated?</h2>
<p>No medications exist to treat a cataract or slow its progression. Stronger spectacles may be all that is needed to manage early cataracts. However, surgery may eventually be required as a cataract progresses and causes troublesome vision impairment. </p>
<p>Cataract surgery has been practised for thousands of years and has involved the same principle: removal of the cloudy lens. The <a href="http://news.bbc.co.uk/2/hi/health/7194352.stm">Romans used to do this</a> by inserting a sharp needle into the eye and rotating it. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/135597/original/image-20160826-17859-1vs4yv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/135597/original/image-20160826-17859-1vs4yv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/135597/original/image-20160826-17859-1vs4yv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=420&fit=crop&dpr=1 600w, https://images.theconversation.com/files/135597/original/image-20160826-17859-1vs4yv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=420&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/135597/original/image-20160826-17859-1vs4yv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=420&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/135597/original/image-20160826-17859-1vs4yv4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=528&fit=crop&dpr=1 754w, https://images.theconversation.com/files/135597/original/image-20160826-17859-1vs4yv4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=528&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/135597/original/image-20160826-17859-1vs4yv4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=528&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 most common type of cataract surgery performed in Australia is called phacoemulsification.</span>
<span class="attribution"><span class="source">from shutterstock.com</span></span>
</figcaption>
</figure>
<p>The most common type of cataract surgery performed in Australia is called phacoemulsification. Typically, an uncomplicated surgery <a href="http://www.cataractcare.com.au/faq">lasts just under ten minutes</a> and is done as a day procedure.</p>
<p>Local anaesthetic is used to numb the eye and a small incision is made through the front of the eye; a hand-held ultrasound probe then breaks apart the cloudy lens contents. This material is suctioned out of the eye and a plastic lens is inserted in its place. </p>
<p>Cataract surgery is one of the <a href="http://www.aihw.gov.au/eye-health/cataract-surgery/">most frequently performed procedures</a> in Australia and has a very high success rate. </p>
<p>Although very uncommon, <a href="http://www.nhs.uk/Conditions/Cataract-surgery/Pages/Risks.aspx">complications can occur</a>. These include retinal detachment, infection, incorrect refractive power of the lens, swelling of the cornea and dislocation of the newly implanted lens. These rare complications may require further surgeries or medications and could lead to permanent visual impairment in the affected eye.</p>
<h2>Can we prevent cataracts?</h2>
<p>The progression of age-related cataract may be slowed by <a href="http://www.ncbi.nlm.nih.gov/pubmed/21617534">wearing sunglasses</a> when outdoors from an early age, avoiding smoking, carefully controlling blood sugar levels if diabetic, and consuming plenty of fruits and vegetables. </p>
<p>Antioxidant supplements are sometimes recommended for prevention of cataracts. Unfortunately, studies have shown these to <a href="http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD004567.pub2/abstract">be ineffective</a>.</p>
<p>If you experience symptoms of a cataract, the first point of call should be an optometrist who can perform a bulk-billed eye examination and refer you to an ophthalmologist if a cataract is found. </p>
<p>However, wait lists for public hospital clinics may be lengthy (months, to over a year) for minor cataracts not severely affecting vision.</p>
<hr>
<p><em>The author thanks Dr Cameron McLintock, ophthalmology registrar at Queensland Health, for his contributions to this article.</em></p><img src="https://counter.theconversation.com/content/63699/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>More than a million Australians have an untreated cataract and hundreds of cataract surgeries are performed daily, but what are they?Jason Yosar, Associate Lecturer, School of Medicine, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.