November 2006
Fending off the damage of the sun
Illustration by
Coco Masuda
Coco Masuda
Eyeglass manufacturers, retailers, and advertisers have long been delivering alarming messages about the damaging effects
of ultraviolet light on the eye--so much so that many eyeglass wearers pay as much as $25 extra for a UV-blocking coating
for their lenses.
But you probably don’t really need it. Even without a UV coating, all types of clear-plastic prescription lenses block the most dangerous part of the UV spectrum, UVB, which can cause cataracts, or the clouding of the eye’s lens. Polycarbonate, high-index, and Trivex plastic lenses also block almost all of another type of ultraviolet radiation, UVA. Only CR-39 plastic lenses allow a significant part of the UVA spectrum to reach the eye. While there’s been some speculation that UVA might contribute to macular degeneration, a deterioration of the retina that can lead to blindness, researchers now believe that the lens and cornea of the eye prevent UVA rays from reaching the retina. Still, Gregory Good, a professor of clinical optometry at the Ohio State University College of Optometry, recommends that you get it on CR-39 lenses just to be safe.
There’s further evidence to suggest that UV protection cannot guard against other damaging effects of sunlight. Research now shows that visible violet, blue, and green sunlight is much more likely than invisible, ultraviolet light to contribute to macular degeneration. (People with blue eyes, fair skin, and a family history of macular degeneration are especially susceptible to damage from such light.)
What can screen out those harmful visible rays? Plain, old-fashioned sunglasses, Good says. For best results, he adds, choose sunglasses or clip-ons with a moderate amount of blue-blocking amber or brown tint. (Green tints are the next best choice. Grays provide the least protection.)
Also, because up to 50 percent of sunlight can reach your eyes from around your frames, choose glasses that fit closely to your face and wrap around your temples. “Transitions,” and other polychromatic lenses, which darken in reaction to sunlight, provide some protection. But they don’t work well in cars, where the windshield and the roof block much of the UV radiation that Transitions need to trigger the maximum darkness change.
If you are out in strong sunlight, wear a brimmed hat or visor. And if you smoke, stop. Smoking is more damaging to eye health than normal exposure to the sun.
But you probably don’t really need it. Even without a UV coating, all types of clear-plastic prescription lenses block the most dangerous part of the UV spectrum, UVB, which can cause cataracts, or the clouding of the eye’s lens. Polycarbonate, high-index, and Trivex plastic lenses also block almost all of another type of ultraviolet radiation, UVA. Only CR-39 plastic lenses allow a significant part of the UVA spectrum to reach the eye. While there’s been some speculation that UVA might contribute to macular degeneration, a deterioration of the retina that can lead to blindness, researchers now believe that the lens and cornea of the eye prevent UVA rays from reaching the retina. Still, Gregory Good, a professor of clinical optometry at the Ohio State University College of Optometry, recommends that you get it on CR-39 lenses just to be safe.
There’s further evidence to suggest that UV protection cannot guard against other damaging effects of sunlight. Research now shows that visible violet, blue, and green sunlight is much more likely than invisible, ultraviolet light to contribute to macular degeneration. (People with blue eyes, fair skin, and a family history of macular degeneration are especially susceptible to damage from such light.)
What can screen out those harmful visible rays? Plain, old-fashioned sunglasses, Good says. For best results, he adds, choose sunglasses or clip-ons with a moderate amount of blue-blocking amber or brown tint. (Green tints are the next best choice. Grays provide the least protection.)
Also, because up to 50 percent of sunlight can reach your eyes from around your frames, choose glasses that fit closely to your face and wrap around your temples. “Transitions,” and other polychromatic lenses, which darken in reaction to sunlight, provide some protection. But they don’t work well in cars, where the windshield and the roof block much of the UV radiation that Transitions need to trigger the maximum darkness change.
If you are out in strong sunlight, wear a brimmed hat or visor. And if you smoke, stop. Smoking is more damaging to eye health than normal exposure to the sun.
