SUNLIGHT AND EYE PROBLEMS
Malignant melanoma, a cancer that grows from pigment cells either of the skin or of the eye, is about three times more common in our southern states than in the North, the New England Journal of Medicine (313:789) reports, and the factor responsible seems to be the ultraviolet light in sunshine.
Not surprisingly, therefore, people with brown eyes (whose eyes are protected by the pigment) are only about half as likely as those who are blue-eyed to develop a melanoma of the eye. Furthermore, those who do develop this cancer are likely to have spent more time farming, gardening, or sunbathing outside, or tanning indoors with a lamp. Lastly, the report indicates the importance of protecting our eyes with a hat, visor, or sunglasses, which, if used routinely, reduce the risk of eye cancer by about 50 percent. Clearly, therefore, sunlight is a big factor in eye cancer, but one we can largely avoid. UV-filtering sunglasses should be worth their extra cost!
Sunlight is also an important factor in the development of cataracts, the Western Journal of Medicine (143:511) reports. Ultraviolet light (UV) causes the deposition of minute granules of an opaque brown pigment in the normally clear and colorless body of the lens. After many years, if the eyes continue to be exposed to strong sunshine, more and more granules are deposited until the lens becomes completely opaque, with blindness as a result. Vision can be instantly restored, of course, by surgically removing these cataracts and replacing them with artificial lenses. The more we expose our eyes to UV, it has been found, the more opaque our lenses become. Not surprisingly, therefore, cataracts are much more common in the tropics than in the temperate zones of Europe and North America. Furthermore, they are less common in office workers than among people who work outside.
Along the same line, the British Medical Journal (65:869) reports that in the tropics people need reading glasses at an earlier age than they do in a cold climate. The average age at which glasses are first needed varies from 36 at one climatic extreme to 50 at the other. Again, stronger light could well be the factor involved, and people should be careful to wear sunglasses when exposed to bright sunlight.
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