One way to reduce greenhouse gas emissions is to phase out incandescent lighting in favour of more energy-efficient lighting. But such a move could see an increase in the number of people suffering from eye disease.
The shift has already taken place in Australia and the European Union. In the United States, federal law stipulates that incandescent lights be phased out by 2014.
It’s estimated that the change in lighting type in Australia alone will reduce greenhouse gas emissions by approximately 28 million tons between 2008 and 2020. So a global move toward ﬂuorescent lighting in the home could lead to signiﬁcant reductions in greenhouse gases.
Incandescent lights are being replaced with energy efficient types of lighting such as high-intensity discharge (HID) lamps, light-emitting diodes (LEDs), and ﬂuorescent lighting, including the popular compact ﬂuorescent lamps (CFLs).
All these light sources are more efﬁcient than the incandescent lamps, with:
HID lamps being less energy efﬁcient than ﬂuorescent lights, but used widely for lighting large areas, such as streets and sports facilities;
LEDs being energy efﬁcient but not as bright, stable, or cheap as ﬂuorescent lights and;
flourescent lighting being the most energy efficient, and also producing the best light to work under. These lights use 75% less energy than incandescent lamps, but emit UV radiation.
Given the efficiency of fluorescent lights, it’s not surprising that they are the most popular lighting option. But many people are now exposed to additional UV radiation emitted from these lights.
The dangers of UV radiation
UV radiation from the sun can damage eyesight. Most people, for instance, are aware of the importance of not looking directly at the sun, and operators of arc welders know to wear protective goggles.
Less attention has been paid to the potentially damaging effects of UV radiation from indoor light sources, such as ﬂuorescent lighting, which is now a signiﬁcant source of UV radiation.
The lights vary in terms of colour temperature, conventionally stated in kelvin (K), and there are variations and inconsistencies among manufacturers.
The safe range of light to avoid exposing the eye to potentially damaging UV light is approximately 2000K to 3500K and greater than 500nm (nanometers are a unit of length). UV wavelengths less than 500nm (and certainly less than 380nm) are capable of irreparable damage to the eye.
Unfortunately, some fluorescent lights currently fall outside this safe range.
The warmer CFLs, which are usually less than 3500K, are less damaging to the eye but produce light that’s often inadequate for concentration at work.
The ﬂuorescent lighting used indoors, particularly in commercial settings, is often in the form of cool-white tubes with a colour temperature of 4000K or greater.
Exposure to UV through fluorescent lighting may increase related eye diseases by up to 12%, leading to an additional 10000 additional cases of eye disease each year.
Our estimates are conservative as they’re limited by a lack of data on the incidence and etiology of many eye diseases, particularly degenerative eye diseases.
But if UV radiation was shown to cause this degenerative eye disease, it would have signiﬁcant public health implications.
What evidence we have suggests the least hazardous approach to lighting from a health perspective is to use warm-white tubes or incandescent bulbs of lower colour temperature and longer wavelength light rather than ﬂuorescent lamps.
Unfortunately, anything other than ﬂuorescent lighting is considered inadequate for many workplaces and in the home.
We recommend UV ﬁlters become a required standard. Lamp manufacturers should not allow current levels of emission of UV light from ﬂuorescent lighting to increase and should work toward reducing emissions.
Further research is also needed to improve lighting from artificial sources. We must be mindful of potential adverse health implications of future changes to technology.