One of our favorite things about summer is the excuse to buy a new pair of sunglasses. But while we’ve become more clued-in on the importance of sunscreen for our skin (even if we don’t always use it), a lot of us still think of sunglasses as a fashion choice rather than a health one.

Time to ditch that bad habit! Dr. Steven Klein, OD, a therapeutic optometrist in sunny San Diego, explains that just like skin, your eyes need protection from the sun’s UVA and UVB rays all year round. “Protect your peepers! You should always wear sun protection while outdoors, even when it’s cloudy, as harmful UV rays are still present,” Klein says. “That includes people who wear eyeglasses: You can now have UV protection in a clear lens.” No more excuses — make this the year you get yourself sunglasses with substance as well as style.

Woman wearing sunglasses

What’s the danger?

The sun’s UV rays come in three types: UVA, UVB, and UVC. The last one is the most dangerous, but luckily for us, these rays are blocked by Earth’s atmosphere. UVA rays have a longer wavelength than UVB rays and make up most of the UV radiation we come into contact with. UVA rays can penetrate to your retina at the back of your eye, causing damage that can eventually lead to macular degeneration, which the National Eye Institute (NEI) identifies as the leading cause of blindness in the US.

Meanwhile, UVB rays have a shorter wavelength, which means they are most dangerous to the cornea, the clear outer layer of your eye. Overexposure to UVB rays can cause photokeratitis, known as “snow blindness,” which is a painful inflammation of the cornea that causes significantly impaired vision. As the nickname suggests, it often occurs when you’re around snow, which reflects more than 80 percent of UVB rays back into your eyes, but it can happen anywhere and typically only lasts for 24 to 48 hours.

In addition, UV radiation can cause the formation of pinguecula and pterygium, which are benign but annoying bumps that develop on the white of your eye (the sclera), and cataracts, which are experienced as a gradual blurring or clouding of vision. The NEI estimates that 20 percent of cataracts in the US are caused by sun exposure.

If that all sounds terrifying, don’t worry that’s where sunglasses come in. Here’s what to look out for when you’re picking your next pair (or two… or three) this summer.

UV Protection Is Most Important

No matter how much you love a pair of sunglasses, if they don’t have UV protection, they’re no good. “Eye protection should never be under UV 400: This is the standard set by the World Health Organization,” Klein emphasizes. UV 400 means that the lenses block all UV rays with a wavelength equal to or shorter than 400 nanometers, which includes both UVA and UVB rays. You might also see sunglasses labeled as having 99 to 100 percent UVA and UVB protection, which is also effective, as long as they live up to that promise.

UV blocking on glasses is usually created with a special tint on the lenses. It shouldn’t wear out over time, but if you want to make sure your brand-new pair or last year’s favorites will actually protect you like they say they will, the best way to check is by taking them into an optical store (or to your optometrist) and asking them to test your sunglasses with a UV light meter. It’s quick, and they’ll probably do it for free.

If you’ve been skipping UV protection in your eyewear, we’re not judging but Klein says now’s the time to get professional help. “Ask your doctor about signs of UV damage to your eyes, and about UV protection and keep up with your annual eye exams,” he advises. It takes years for symptoms of the long-term effects of UV rays to show, but it’s better to look into it late than never.

Does price matter?

The good news is that whether you’re spending $5 or $500, most sunglasses that claim to block 99 to 100 percent of UVA and UVB rays actually deliver on that promise.

A consumer study carried out on behalf of CBS in 2010 tested the UV protection of 31 pairs of sunglasses, purchased from street vendors and high-end stores, with prices ranging from $5 to $200. The researchers found that 30 out of the 31 lived up to their labels, blocking 99 to 100 percent of rays.

Another study in 2014, this time conducted by ABC’s Good Morning America, produced similar results, with all 11 of the $10 to $20 sunglasses from pharmacies, fast fashion stores, and street vendors delivering the protection they promised. The main difference between the cheaper pairs and expensive ones (that cost over $100) is not how well they block UV rays, but the design, comfort, and durability of frames.

Make sure they fit

If you’re tempted to give in to the trend for tiny ‘90s shades, keep in mind that they aren’t going to offer you the best protection from UV radiation. The bigger your lenses, the more rays they can keep out of your eyes. Most experts recommend wraparound sunglasses, since these block your eyes at the sides as well as the front. Don’t wear them halfway down your nose, either; you need the lenses comfortably close to your eyes in order to maximize their ability to block UV rays.

Contact lens wearers take note: Although you can now get lenses that block UV rays, they’ll only protect your cornea. Treat these as an additional shield, rather than the only protection you rely on, and get yourself a pair of big UV-blocking sunglasses too.

Does Lens Color or Darkness Make a Difference?

As you know, but may not have thought about, sunlight also produces visible light. This is less dangerous than UV rays but can have an impact over time.

Dr. Andrea Thau, OD, a New York-based optometrist who served as the president of the American Optometric Association (AOA) from 2016-2017, told CNN that extensive exposure to visible light, “does bleach your receptors, and some studies have indicated it can impair your night vision and your color vision perception.” She recommends sunglasses with an opacity of 75 percent or higher on sunny days. If you’re going in and out a lot, like at a barbecue or party, try photochromic lenses (also known as transitional lenses), which automatically go dark when exposed to the sun’s UV radiation, then clear when you’re inside.

However, keep in mind that darker lenses don’t mean more UV protection. It’s extra-important to check for this, because when you wear dark lenses, your irises expand to let more light in, and therefore also more of that damaging UV radiation, if you aren’t properly protected.

The part of visible light that eye experts are most concerned about is blue light the same light that comes from phone and computer screens. Scientists are currently unsure about the exact impact of blue light on human eyes, especially from screens, but one study found that even short exposure to blue light from the sun could damage the retina.

Although lens color is less important than UV protection, certain colors are better at blocking blue light. CNN also interviewed New Orleans-based environmental medicine specialist Dr. James H. Diaz, who explained that orange and yellow lenses have been shown to be the most effective, while blue and purple are the worst. However, the risk from blue light is much lower than from UV rays, and eye experts aren’t too concerned about your color preferences. Thau says the most popular lens colors are gray, green, and brown, but as long as those rose-tinted glasses have UV protection and they fit you right, you can rock them all summer and winter long.

Did you get a new pair of stylish and protective shades? Show us your new sunglasses in action by tagging us on Instagram @BritandCo.

(Photo via Getty)