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Ozone depletion: cause for caution, not alarm.

While studies have associated ultraviolet-B light exposure with the formation of cataracts, it will take decades to determine whether changes in the ozone layer, which predominantly blocks UV-B from the Earth's surface, will have a measurable effect on the general population. "We continue to urge the use of UB-absorbent sunglasses, but no one should be concerned that they or their children will develop cataracts overnight because they stayed out in the sun unprotected," maintains Gerald A. Fishman, a spokesman for the American Academy of Ophthalmology and an authority on sunlight and its association with eye disease. "Even if higher UV-B exposure can be demonstrated to have an effect, cataract formation will continue to occur slowly and the loss of vision will be gradual."

However, there are a number of other ocular risks associated with unprotected exposure to bright sunlight and other sources of strong UV light. As with cataracts, most greatly are reduced by wearing proper protection.

* Burns. Excessive exposure to ultraviolet light without protective eye wear can cause a sudden, temporary, and painful burn to the surface of the eye. Ultraviolet-induced keratoconjunctivitis, sometimes called snow blindness, often is observed a few hours after skiing, sunbathing, or arc welding. The burn results in severe pain and often a temporary inability to open the eyes comfortably.

* Chronic UV exposure may contribute to an abnormal growth on the surface of the eyeball called a pterygium. It most often is encountered among farmers and other outdoor laborers, especially in the Sunbelt states. A pterygium can grow over the cornea, partially blocking vision. Surgery to remove it usually is recommended if sight appears threatened.

* Visible light usually is not damaging to the eye. A flash of bright light merely will bleach pigments temporarily, causing spots in the visual field. However, staring directly at the sun, a source of intense visible light, will burn--and permanently scar--the retina. UV-absorbent sunglasses can not protect the eye from damage caused by staring at the sun.

* Photosensitizing chemicals can make the eyes especially sensitive to sunlight. These include psoralen compounds, used to treat psoriasis, and certain antibiotics, such as tetracycline and sulfa drugs.
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Publication:USA Today (Magazine)
Date:Feb 1, 1993
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