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
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
Your best bet is to look
for sunglasses that claim to block most or all UV. For example, "99%-100%
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-coloured eyes are particularly
vulnerable to UV, according to the news release.
Prevent Blindness America
has more about protecting your eyes from the sun.