Several shelves full of sunglasses

W hen you think of the damage the sun can do, your first thought may be of the ultraviolet (UV) radiation that can burn your skin, increasing your risk of skin cancer. What you may not realize is that the sun can hurt your eyes as well.

“I think people are aware of skin damage from UV simply because sunburn hurts,” says Joan E. Roberts, Ph.D., a professor of chemistry at Fordham University Lincoln Center in New York. In most cases, sun damage to the eyes accumulates slowly over time, without your noticing until irreversible harm has been done, Roberts says.

That harm can include several conditions that can affect your ability to see, a rare form of eye cancer, and skin cancer.

Just as sunscreen shields your skin by blocking UV radiation, sunglasses can shield your eyes from harmful rays. But not every pair is equally effective. Here’s what to know about how the sun can injure your sight, and how sunglasses can help safeguard your eye health.

Health Risks to Your Vision

Evidence suggests that excessive exposure to sunlight is a risk factor for cataracts, a clouding of the eye’s lens that can blur vision. For instance, a 2014 study published in the journal Investigative Ophthalmology & Visual Science found that people who lived in places with more sunlight are more likely to need surgery to remove a cataract than those living elsewhere.

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Sunlight may also contribute to an increased risk of macular degeneration (MD), which occurs when the macula, a part of the retina, becomes damaged, causing distortions in what you see, blurriness, or difficulty discerning fine details. Although the link between sunlight and MD isn’t definitive, an analysis of 13 studies, published in 2019 in the journal International Archives of Occupational and Envi­ron­mental Health, found that outdoor workers with long-term exposure to sunlight were more likely to have the condition.

According to the American Academy of Ophthalmology, long-term exposure to sunlight may also be a risk factor for melanoma on the surface of the eye. Skin cancers can also occur on the skin around the eyes, including the eyelids. Looking directly at the sun or the bright glare from water, snow, or ice for too long can also damage parts of the eye, causing a condition called photokeratitis. Symptoms include temporary discomfort, blurriness, and light sensitivity.

The Right Sunglasses Can Help

To help limit your exposure to sunlight, wear a hat and sunglasses when you head outside, even on cloudy days, advises Marilyn Schneck, Ph.D., a scientist with the Smith-Kettlewell Eye Research Institute in San Francisco. And keep the following in mind while choosing your shades:

Look for the most protection. Opt for a pair whose label says the product blocks 99 to 100 percent of UVA and UVB rays, two concerning types for eyes. (The term “UV 400 nm” also means the glasses block at least 99 percent of UV rays.) If you wear corrective lenses, make sure they have UV protection built in.

Know that pricier isn’t always better. Confused about pricing? The most effective sunglasses aren’t necessarily more expensive. You can easily find inexpensive sunglasses that have 100 percent ultraviolet-blocking ability.

Go big. Even while wearing sunglasses, some of the sun’s rays can reach your eyes and the skin around them. Larger lenses can help maximize sunglasses’ ability to stop rays from reaching your eyes. Wraparound sunglasses, which conform to the curve of your face, are even better. They have the added bonus of protecting the skin around your eyes, which is difficult to cover with sunscreen.

Take care after cataract surgery. Although a cataract impairs vision, the cloudy yellowing of the lens also blocks some potentially damaging blue light from reaching the retina. Once the cataract is removed surgically, more blue light reaches the back of the eye. Wearing sunglasses and a hat can help protect the retina after you have cataract surgery.

Editor’s Note: This article has been updated to include a story that appeared in the August 2020 issue of Consumer Reports On Health