SATURDAY, Oct. 5, 2013 (HealthDay News) -- A good pair of sunglasses can help protect your eyes from sun-related damage, so you need to know what to look for when shopping for a new pair, experts say.
Long-term exposure to ultraviolet (UV) rays from the sun is associated with a number of eye conditions, including cataracts, skin cancer on the eyelid and around the eyes, melanoma of the eye, and benign growths on the surface of the eye, according to researchers at the University of California, Berkeley.
In the United States, there are no federal standards for sunglasses and labels are inconsistent and confusing. Tags or stickers that say "blocks UV" or "UV absorbent" are meaningless because they don't tell you how much UV is blocked.
Your best bet is to look for sunglasses that claim to block most or all UV. For example, "99-100 percent UV absorbent" or "UV 400." However, there is no independent verification for such claims, so you might want to have an optician test your sunglasses to find out if they block all or most UV, the UC Berkeley researchers noted in a university news release.
For those not in the market for a new pair of shades, it might be a good idea to have your old sunglasses tested, because scratches and abrasions can wear down UV coating over time. An optician can also put a UV-protective coat on sunglasses.
Be aware that darker lenses don't necessarily provide greater UV protection. And, darker lenses that don't block UV can be more harmful than wearing no sunglasses at all because they cause pupils to open wider and allow more UV to enter your eyes.
The larger the frames of your sunglasses, the better. Wrap-around sunglasses block light coming in through the side, according to the news release, but they may cause distortion.
Everyone should wear sunglasses when spending time outdoors, including children (their eyes are especially vulnerable to UV) and people who wear contact lenses. Even if contacts are UV-treated, they don't cover the whole eye.
Sunglasses are essential for people who are sun-sensitive due to medications or other reasons, and for those who have had cataract surgery. Light-colored eyes are particularly vulnerable to UV, according to the news release.
Prevent Blindness America has more about protecting your eyes from the sun.