We can't see ultraviolet light, but at least now we know it's there, and we know that we should protect ourselves from it. Up until the 1930s, sunglasses weren't widely available. Protecting our eyes from the sun meant wearing a wide-brimmed hat. Nowadays, we know that ultraviolet (UV) radiation can lead to serious eye damage, including cataracts, cancer, snow blindness, and more commonly, photokeratitis, which amounts to an eye sunburn. Ouch.
UV radiation from the sun can reach our eyes in many ways - bouncing off water, clouds, snow, and the windows of buildings and passing cars. And not all of the sun's light affects our eyes in the same way. 95% of all of the UV radiation that reaches the Earth's surface are UVA rays; the other 5% is UVB radiation. The outer layers of our eyes act like natural sunglasses, shielding our retinas from most UV radiation: UVB is fully absorbed by the cornea of the eye, and UVA passes through the cornea but is filtered by the lens of the eye. Only about 1% or less of UV radiation actually reaches the retina.
Although UVB is the type of radiation associated with eye damage, UVA can also play a part (e.g., in the formation of cataracts). In general, UVA or UVB protection is required as neither has proven to be good for our eyes.
Staying out of the sun during the peak UV hours of 11 am to 4 pm is not always possible. And wearing a hat provides minimal protection, as do regular eyeglasses. To best block out the harmful UV rays, your eyes need more protection.
When you're shopping for sunglasses, consider these 4 things that matter:
- Numbers matter. When shopping for sunglasses, look for labels that say the lenses block out 99% to 100% of UV radiation. Make sure they block out both UVA and UVB rays.
- Fit matters. Poorly fitted sunglasses may not provide enough protection. You may be less likely to wear glasses that feel awkward or uncomfortable. And when glasses are too small or too large, they may let in light from the sides. Athletes have the right idea with wraparound sunglasses.
- Lenses matter. Polarized lenses deflect glare but don't offer UV protection. Lenses made from real glass provide little protection at all. Your best choice these days? Polycarbonate plastic lenses. These tougher lenses provide adequate UV protection and are sturdier than other varieties. Photochromic lenses are also a good option because they block glare and UV radiation while maintaining visual sharpness.
- Functionality matters. Options exist for those who have a hard time wearing sunglasses. If you wear eyeglasses, try prescription sunglasses, tinting for your eyeglasses, or clip-on lenses with UV protection. New contact lenses are available with enhanced protection, but sunglasses should still be worn.
Okay, now for 4 things that don't matter too much:
- Age. Children's eyes need even more protection from the sun than adults. But if you take a look around next time you head out to the pool or beach or playground, you'll notice lots of adults wearing sunglasses but very few kids with any eye protection at all. Because of their clearer corneas and lenses, children's eyes let in more UV light than the more fully developed eyes of adults and thus are at even higher risk of sun damage. Many sunglasses manufacturers offer kids' styles. Let your kids pick out whatever fun frames they'd like, but just make sure to choose a pair with 99% to 100% UV protection.
- Season. Our eyes need sun protection all year long, so don't wait for summer to shop for sunglasses. During the fall and winter, you may see the sun less often, but that doesn't mean its effects aren't felt by our eyes. Sea foam, beach sand, and snow: they all reflect damaging UV light into our eyes. In fact, winter snow reflects much more UV light than dry sand.
- Lens colour. For the most part, the colour of lenses in sunglasses shouldn't make a difference in protection. Shades with super-dark lenses may work for celebs wanting to go incognito, but dark lenses provide no extra sun safety. Sunglasses with amber-coloured "blue-blocking" lenses may block out visible blue light (which may damage the retinas ), but they don't provide adequate defence against UV radiation.
- Cost. Spending more won't necessarily buy you superior protection. Lots of people shell out a bundle for designer shades, while others go cheap and hope for the best. Instead, just look for labels that say the lenses block out 99% to 100% of UV rays.