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How to Tell If Your Sunglasses Are Really Protecting Your Eyes

Those sunglasses you just bought may look ultra-cool, but save them for selfies if they're not filtering out the sun's harmful ultraviolet (UV) rays. After all, not all sunglasses are created equal. Whether vintage, cheap, expensive, or polarized, they may or may not do their job to protect your precious eyes.

In particular, older sunglasses may not be as effective as you think. Most sunglasses today have UV protection embedded in the lens rather than coated over it, and most reputable brands list UV protection on their label. Look for a label that says either of these two things:

  • 100% protection against both UVA and UVB
  • 100% protection against UV 400

If you're uncertain about your sunglasses—or those fun pairs you bought online for the kids—simply take them to an optical shop, where they can be tested in a photometer. Most opticians will test them for free, and it takes less than 30 seconds.

How to pick the best sunglasses

You really don't need to spend big bucks for UV-protecting glasses, but here's more of what you do need to know:

  1. Dark sunglasses don’t offer more protection.In fact, dark sunglasses that don't block harmful rays may reduce your need to squint in bright light, but that's about it. When you put on a very dark pair of sunglasses, your pupils open up and allow much more light into your eyes than if you didn't wear those sunglasses at all. So, while they may filter out ambient light and glare, that additional exposure to UV rays increases your risk for cataracts, macular degeneration, and even the development of ocular melanoma—a rare cancer.
  2. Polarization has nothing to do with UV light absorption, but many polarized lenses are now combined with a UV-blocking substance. Check the label to make sure the lenses provide maximum UV protection. The same goes for lens color and tint, lens darkness, and mirror coating.
  3. Consider wrap-around sunglasses if you spend a lot of time outdoors, especially around water. These sunglasses protect from UV rays that come in from the side. This design will also stop the wind that makes your eyes dry. They don't have to be expensive. They just have to fit well—and of course, you have to keep them on as long as you are in the sun. That goes for kids of all ages, too.

"The most important advice is to put on your sunglasses whenever you are outside," says Jeff Pettey, MD, MBA, an ophthalmologist at John A. Moran Eye Center at University of Utah Health. "And put them on your kids, please. Sunglasses are to the eyes what sunscreen is to the skin. Whether it's cloudy or sunny, they are an essential shield to protect your health."