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We protect our skin with sunscreen, but what about our eyes?

Most of us are aware of the dangerous effects ultraviolet (UV) rays have on our skin, but few of us realize the danger imposed on our eyes.

UV radiation, whether from natural sunlight or artificial UV rays, can damage the eye's surface tissues as well as the cornea and lens. UV radiation can burn the front surface of the eye, much like a sunburn on the skin.

UV radiation consists of invisible rays from the sun.

There are three types of UV radiation: UVA, UVB and UVC.

UVC rays do not pose any threat, as they are absorbed by the ozone layer. However, exposure to UVA and UVB rays can have adverse effects on your eyes and vision. Short- and long-term exposure to these dangerous rays can cause significant damage damage. It is important to note that UV radiation can also be given off by artificial sources like welding machines, tanning beds and lasers.

Two types of harmful light rays come from the sun:

ultraviolet A radiation (UVA), and ultraviolet B radiation (UVB).

• UVA radiation can cause photoaging, or premature aging of the skin, resulting in wrinkles, uneven pigmentation, and texture changes.
• UVB radiation is the main cause of sunburn.

Short-Term Effects of UV Radiation

If you are exposed, unprotected, to excessive amounts of UV radiation over a short period of time, you are likely to experience an effect called photokeratitis. Photokeratitis is an inflammation of the cornea caused by a brief exposure to UV radiation, usually when combined with cold wind and snow. Like a "sunburn of the eye", it may be painful and may create symptoms including red eyes, a foreign body sensation or gritty feeling in the eyes, extreme sensitivity to light and excessive tearing. Fortunately, this is usually temporary and rarely causes permanent damage to the eyes.

Long-Term Effects of UV Radiation

Long-term exposure to UV radiation can be more serious. Scientific studies and research growing out of the U.S. space program have shown that exposure to small amounts of UV radiation over a period of many years may increase the chance of developing a cataract, and may cause damage to the retina, the nerve-rich lining of the eye that is used for seeing. This damage to the retina is usually not reversible. Cumulative damage of repeated exposure may contribute to chronic eye disease, as well as increase the risk of developing skin cancer around the eyelids. Long-term exposure to UV light is also a risk factor in the development of pterygium (a growth that invades the corner of the eyes) and pinguecula (a yellowish, slightly raised lesion that forms on the surface tissue of the white part of your eye.)

UV Radiation Protection

It is not yet known how much exposure to UV radiation will cause how much damage, but a good recommendation is to wear quality sunglasses that offer good protection and a wide-brimmed hat when working outdoors, participating in outdoor sports, taking a walk, running errands or doing anything in the sun.

To provide protection for your eyes, your sunglasses should:

• block out 99 to 100 percent of both UV-A and UV-B radiation

• screen out 75 to 90 percent of visible light

• be perfectly matched in color and free of distortion and imperfection

• have lenses that are gray for proper color recognition

If you spend a lot of time in bright sunlight, wrap-around frames can provide additional protection from harmful UV radiation by keeping UV rays from reaching the eyes. Also, remember UV eye protection for children and teenagers. eResearch by Navid Ajamin -- summer 2013

They typically spend more time in the sun than adults. Finally, even if you are wearing contact lenses that have UV protection, you still need to wear sunglasses.UV rays will likely affect the eye tissue that is not covered by the contacts. Your eyes will be more comfortable, too, with most of the bright light blocked.

Reference: Vision.about.com Source: American Optometric Association. U/V Protection. 14 Jun 2007.