Consumers know about the danger of sun exposure to the skin. But most consumers aren't aware that exposure to the sun can also have a detrimental effect on your eyes. Sunlight responsible for damage to the eyes is called ultraviolet or "UV" radiation.
There are two types of UV radiation, UV-A and UV-B, that can have damaging effects on our vision. UV-A is longer wavelength radiation that usually induces skin tanning and browning. UV-B is more active, shorter wavelength radiation that causes blistering sunburn and is associated with skin cancer. Excess exposure to intense sunlight can burn the surface of the eye much like sunburn on the skin.
Although our eyes provide some natural protection from the sun's harmful rays, overexposure to sunlight can seriously damage vision. The earth's diminishing ozone layer, which filters out less UV light, makes humans more susceptible to ultraviolet rays.
You do not have to be basking on a sunny beach to have your vision compromised. Ultraviolet light is strongest when it is reflected off snow, sand or water. Even light reflected off pavement can produce a burn on the surface of the eye.
Studies show that over time, exposure to ultraviolet light can contribute to a number of complications to your eyes. Some are temporary, but others can permanently compromise vision or require expensive surgery.
Burns. Over-exposure to ultraviolet light can cause a sudden but temporary, painful burn to the eye's surface. Photokeratitis, or "snow blindness,"can occur a few hours after activities like skiing or sunbathing. Staring directly at the sun -- a source of intense visible light -- can permanently scar the retina, the delicate lining at the back of the eye responsible for vision.
Cataracts. Exposure to UV radiation over many years is one cause of cataracts, a clouding of the lens. Moreover, if you've had cataract surgery to restore vision, you may be even more vulnerable to the sun's ultraviolet rays. Why? During this procedure, doctors replace the eye's natural lens with a synthetic lens, which provides less natural UV protection.
Pterygium (pronounced te-rij-e-um), or a benign, abnormal growth on the eye's surface. A pterygium can also grow over the cornea, partially blocking vision, as a result of chronic UV exposure. If sight is threatened, surgery may be required to remove a pterygium.
Macular degeneration. A condition that causes age-related damage in the central vision area, macular degeneration is the major cause of blindness among Americans over age 50 and has been linked to cumulative UV exposure.
Cancer of the eyelids and skin around the eyes can be traced to UV overexposure.
What can consumers do to protect eyes from potentially harmful ultraviolet rays? According to the American Optometric Association, sunglasses provide one of the best sources of UV protection. While some contact lenses are now available with UV protection, they should not take the place of sunglasses. Sunglasses block out 99 to 100 percent of UV-A and UV-B radiation, and also shield the eyelids from sun exposure. UV-absorbing contact lenses do not provide this level of protection and do not provide adequate coverage for the entire eye area. As a general rule of thumb, if you are in enough sun to cause a sunburn, you need protection for your eyes.
When choosing sunglasses, keep in mind the following guidelines:
Experts believe that sunglasses with 100 percent UV protection
are the best defense to protect the eyes against harmful UV rays.
UV-absorbing contact lenses should not be used as substitutes
for sunglasses, since they do not provide 100 percent UV protection.
Some medications contain photosensitizing chemicals that make the eyes especially sensitive to the sunlight. Talk to your doctor about possible sun-induced side effects if you're taking the following medications:
Children's eyes are more susceptible to UV exposure because
the lens in their eye is clearer. With age, lenses darken and
tend to block more UV light to the back of the eye.