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Regular-article-logo Wednesday, 01 May 2024

Photochromatic glasses give best UV protection

Regular eyeglasses and sunglasses should have anti-reflective coating on both sides of lenses

Jane E. Brody / NYTNS Published 27.08.19, 01:45 PM
Although we have been admonished for decades about the need to protect our skin from sun damage, relatively few such warnings have been issued about eyes, and there is still no SPF mandate for sunglasses

Although we have been admonished for decades about the need to protect our skin from sun damage, relatively few such warnings have been issued about eyes, and there is still no SPF mandate for sunglasses NYTNS

Many people my age with lens implants following cataract surgery are thrilled not to have to wear glasses, but I’ve recently gone in the opposite direction. Although at 78 I can still drive and even read the newspaper without corrective lenses, I’ve chosen to wear glasses nearly all the time.

Within the past two years, I’ve invested in multiple pairs of prescription glasses with progressive “transition” lenses, which darken in sunlight to become sunglasses. They provide visual enhancement and protection and serve as a fashion statement. If and when I need to have cataract surgery and require a new prescription, I’ll replace the lenses in my favorite eyeglass frames and continue to wear them.

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Glasses have in effect become my jewelry, and I’ve been amazed at how many compliments they inspire. But even more amazing is what the glasses have done for the safety and comfort of my eyes, protecting them from dust, bugs, drying breezes and, most important of all, the damaging effects of ultraviolet light.

Although we have been admonished for decades about the need to protect our skin from sun damage, relatively few such warnings have been issued about eyes, and there is still no SPF mandate for sunglasses. As a result, UV light has compromised the eye health and vision of far too many people of my vintage, myself included. I now have an irritating growth called a pterygium on the white of one eye, a result of many decades spent outdoors without proper eye protection.

Happily, things are changing. I now often see babies and toddlers, as well as their caretakers, wearing sunglasses.

Ocular sun damage can occur any time of the year and even when it’s hazy or cloudy. Skiers can fall victim to snow blindness, a temporary impairment. But cumulative exposure to ultraviolet rays can cause permanent damage, including cataracts, pterygiums, premature presbyopia (the inability to see small print), precancerous growths on the eyelids and, current evidence suggests, melanoma of the iris and age-related macular degeneration. People who work outdoors are especially vulnerable, as are those who live at high altitudes. Sunlight hitting the eyes directly is not the only source of UV damage. These harmful, invisible rays can reach the eyes from behind, below and the sides, kind of an ultraviolet “surround sound.” UV rays are reflected off concrete, sand, water, ice and snow. Even when facing away from the sun, eyes are exposed to reflected UV rays. Clouds and haze increase scattering. Experts called reflected UV an important and underestimated contributor to vision damage.

Here’s what to consider when choosing lenses that can protect your eyes from the hazards of UV overexposure.

All sunglasses should now come with full (400 mm) UV protection, although more expensive lenses provide better visual clarity. The colour of the lens does not matter, though light tints are not as effective for people whose eyes are very sensitive to bright light. If the label says UV 400, chances are it’s true or very close to it.

Michael Stoff, the optician-proprietor at Eye Shoppe on 7 in Brooklyn, where I have bought all my new glasses, told me that the polycarbonate material of most sunglass lenses and lenses made of glass naturally blocks UV rays, but UV protection has to be added to plastic lenses. If in doubt, ask an optician who has a spectrometer to check them. Ideally, both regular eyeglasses and sunglasses should have anti-reflective coatings on both sides of the lens, which is why I spent a little extra to get Crizal lenses.

I also got photochromic lenses in all glasses I might wear outdoors. They have excellent UV protection, Stoff said. When exposed to UV, even on hazy days, the lenses darken, then clear in a minute or so when you go indoors. However, photochromic lenses do not darken in a car because windshield glass blocks UV light. And they do not get as dark as dark-tinted sunglasses so may not work well for eyes very sensitive to sunlight.

You might also consider getting polarized lenses that can reduce glare coming from horizontal surfaces; they’re especially helpful when driving or playing sports. I recently purchased wraparound sunglasses with shatterproof lenses for cycling, to get better peripheral vision while riding and more protection from UV entering from the sides.

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