So what can you do to protect your eyes from this damage, which can lead to redness and blurred vision, and even eye diseases like cataracts and macular degeneration? Wearing sunglasses is an obvious choice—but your stylish pair may not be protecting your eyes as well as you think. Here’s how to tell if you’re wearing the best kind.

Look for the best protection—with the right label.

All sunglasses should have labels that indicate their protection level. You should always look for sunglasses with 100 percent UVA- and UVB-absorbent protection, or UV 400, says Askia Saunders, OD, an optometrist with Eyeconic in Chicago. What exactly do these numbers mean? The sun emits three kinds of ultraviolet waves: UVA, UVB, and UVC, Saunders says. All of these waves have a length of 400 nanometers or smaller, but UVC is absorbed by the earth’s atmosphere, so UVA and UVB are what you need to protect yourself from (both skin and eyes). A pair labeled UV 400 will absorb wavelengths up to 400 nanometers, which is the same as saying 100-percent UVA and UVB absorbent.

Don’t believe just any label, though.

Sounds simple enough, but buyer beware: Not all sunglasses stickers are trustworthy. Sunglasses are regulated as medical devices (they’re intended to mitigate or prevent the sun’s damaging effects on your eyes) by the FDA. However, to ensure their safety and impact resistance, consumer tests have shown that what’s on the sticker isn’t always accurate—especially for cheaper imported brands. (That $10 pair probably isn’t a good deal, after all.)

Get your sunnies from a trusted source.

Instead of ordering or buying sunglasses from any retailer, do some research to be sure you’re going to a reputable source, or ask your eye doctor what brands they recommend for optimal eye protection. You don’t have to pay top dollar for protective sunglasses, but you don’t want to go too cheap, either.

Darker lenses aren’t necessarily better.

Many people believe that darker sunglasses provide better UV protection—but the quality of a pair’s shading has nothing to do with the darkness or color of the lenses. In fact, “dark lenses without adequate UV protection can actually be worse than no sunglasses at all because they cause the eye’s pupil to dilate, which then increases retinal exposure to unfiltered UV,” explains Saunders.

Yes, properly protective shades can be chic.

You don’t have to turn to unsightly pairs, though, to get proper protection. Oversized frames, like you see on so many Hollywood stars, are an excellent choice because they provide extra UV protection by blocking rays that come in from the periphery. Polarized lenses, like the ones from men’s and women’s sunglasses brand Costa Del Mar, are another good option, as they help reduce glare from sunlight reflected off shiny surfaces, Saunders says. It’s completely possible to find a pair of sunglasses that have all the eye protection you need and look stylish, too. Some of Saunders favorite styles for this summer include: retro-inspired Salvatore Ferragamo sunnies, these sunshield-style frames from DKNY, and a rose-colored, 90s-chic pair from Chloe (just in time for a Friends reboot!).