Sunglasses are important to protect eyes from UV rays, but the wrong ones could cause macular degeneration, growth on the eyes, cataracts or blindness.
"Don't go to the dollar store and pick up a cheap pair of sunglasses thinking you're saving money there. In the long run, you're just causing more harm than good," says Dr. Vin Dang.
But you don’t have to buy the most expensive pair to get the maximum protection. What you’re really looking for is UV protection. The sun gives off UV radiation that you can’t see or feel. In small doses, it boosts vitamin D. But too much of it can cause problems like sunburn and skin cancer. It can also damage your eyes.
Sunglasses are regulated by the FDA, and if they're safe they'll have a sticker on them that says, "UV 100%" or "UV 400."
Still some glasses may have only a coating of UV sprayed on them. As people clean off their sunglasses, they're wiping off the UV protection. It only takes a few wipes to take off the UV coating completely. This is why it’s worth investing a little more for your glasses.
Dang says wearing unprotected sunglasses is worse than wearing no sunglasses at all.
"When you're wearing sunglasses, your pupils will dilate. More harmful rays will go into the back of your eyes," says Dang.
Too much UV light can cause cataracts. It can also destroy the retina, the lining at the back of your eyes that helps you see clearly. It could even cause tissue to grow over your eyeball.
UV light can cause changes in cells that lead to skin cancer, says eye doctor Rachel Bishop, MD. It may not lead to cancer in your eyes, but it can thicken tissues around them and cause discomfort.
A pair that doesn’t fit well can let UV rays seep onto your skin and into your eyes.
“I look at something that fits the face well,” says optometrist Fraser Horn, OD. “I don’t want it up touching the eyelashes, but I also don’t want it pushed way out. And I want something that lines up with your brow.”
Sunglasses that wrap around your eyes can help block stray UV light. They can also keep out sand and allergens. Those things aren’t good for your eyes, either.
These reduce glare at the beach, in the snow, or out on the water. But they don’t take the place of UV protection.
You might see better through them when there’s tons of light around. But they can make it harder to see things like computer screens, smartphones, or dashboards.
Darkness and Color
Just because a lens is almost black doesn’t mean it blocks UV rays. So again, read that label.
Your pupil, the black dot at the center of your eye, controls how much light gets in. When you wear darkened lenses, the pupil opens more to let in more light. If your sunglasses aren’t rated to block UV rays, you might let even more into the back of your eye.
What’s best: Shatterproof glass? Plastic? Some newfangled polycarbonate material? Again, it’s a matter of taste. How well they help you see matters a lot, too. Some lenses, especially the more curved ones, can cause distortion. But that’s not always the case.
“If you’re stopping by the gas station on the way to the lake to pick up sunglasses, you’re more likely to have something of lesser quality,” Horn says. But a higher price tag doesn’t always equal great image quality, he adds.
Sunglasses for All
When you pick out your new shades, remember this: Get some for the kids you know. And be sure they wear them, sunny or not.
A 2014 survey by the American Academy of Ophthalmology found that only 32% of parents make their kids wear sunglasses that are rated to block UV light.
“Whenever you’re thinking, ‘Hmmm, I should be using sunscreen,’ you should be wearing sunglasses,” too, Bishop says. “As a parent, you should be aware that [kids] start accumulating that sun damage just as soon as there’s exposure. Kids wearing sunglasses is an important thing.”