Eye-care specialists are cautioning consumers to look beyond this year's cache of handsome frames and trendy designer labels when buying sunglasses.
There's nothing wrong with handsome and trendy, if the glasses also protect the eyes from ultraviolet (UV) radiation. A number of doctors are warning consumers that sunglasses, no matter how dark, may not be fully protecting their eyes.
Dr. Richard W. Young, professor of anatomy and member of the Jules Stein Eye Institute at UCLA, is among the experts who say that sunglasses that do not block ultraviolet light could be more damaging than wearing no sunglasses at all.
Doctors Have Logical Explanation
The doctors' explanation for this is logical. In bright sunlight, the pupil of the human eye naturally constricts, and muscles around the eye contract to a squint. This offers some protection from harmful rays. Behind dark glasses, however, the eye muscles relax and pupils dilate, just as they do upon entering a darkened room. Wide-open eyes and dilated pupils allow more of the sun's harmful rays to enter the eye.
Young, who has been studying the cumulative effects of sunlight on the lens and retina, believes that sunlight (specifically the ultraviolet, blue and violet rays) is the major environmental contributor to age-related cataracts and age-related macular degeneration, which he says are the major causes of blindness in this country.
In individual interviews last week, Young and Drs. Michael Marmor, head of the division of ophthalmology at Stanford University School of Medicine; Sidney Lerman, professor of ophthalmology at Emory University, Atlanta; Charles L. Janes, clinical associate professor of ophthalmology at USC School of Medicine, and Walter Chase, professor at Southern California College of Optometry in Fullerton, all agreed that people ought not to be in bright sunlight for any prolonged amount of time unless they wear glasses that block 99% to 100% of the sun's ultraviolet rays.
"Ultraviolet rays burn the eyes just as much as they burn the skin," Chase explains.
Janes says prolonged exposure to UV light can potentially cause damage, such as growths on the whites of the eye, skin cancer around the eyes, corneal injury (such as snow blindness) and cataracts.
"But so far, we can't prove that UV light causes cataracts," he emphasizes.
However, in recent months, two studies conducted independently by Dr. Lawrence Brilliant for Nepal's Ministry of Health and by Dr. Fred Hollows of the University of New South Wales in Australia have shown a distinct link between cataracts and exposure to the sun's UV rays. Stanford's Marmor points out that the effects of UV rays are cumulative over many years of exposure. "I don't want someone panicking because they forgot their sunglasses for a day and thinking they are going to get cataracts," the specialist says. "But because damage is cumulative, there is cause to be concerned about the kind of sunglasses one wears."
The Sunglass Assn. of America appears not to be so worried. Tom Loomis, president of the group whose 70 member firms sell about 160 million sunglasses per year, says the SAA conducted a study in 1984 that showed average sunglasses absorb 99.9% of harmful UV rays. "And the initial results of our 1986 study look even better than in 1984," he asserts.
David Sliney, a medical physicist with the U.S. Army Environmental Hygiene Agency in Aberdeen, Md., disputes the results of the SAA report. "There are any number of studies in my files showing that a great many glasses transmit UV, but rarely in an amount greater than the amount of visible light transmitted." This means, for example, that many sunglasses that transmit 20% of visible light also transmit 20% of UV rays.
Lerman agrees. "Average sunglasses are not made to give full protection, and people in the Sun Belt states need full protection, especially if they've had their own lenses removed," he says.
Young of UCLA adds: "I have four or five analyses of commercially available sunglasses that show clearly that they do not block 99% of UV rays.
"If we could get people to buy the right sunglasses now, we could help prevent the tragedy of blindness that affects elderly individuals."
The right sunglasses, in his opinion, are those that absorb essentially all ultraviolet radiation, as well as blue and violet rays.
But it's not easy for consumers to tell if they're buying the "right" sunglasses.
Even though many doctors and researchers around the world agree that overexposure to UV can have potentially damaging effects on the human eye, the Food and Drug Administration has issued no federal regulations regarding the labeling of sunglasses. And unfortunately, the consumer has no way of knowing whether a pair of glasses blocks UV unless they are labeled.