Sun Sunglasses

See also: Find out today's UV levels • Do kids really sunglasses?

The UV Index developed by the U.S. Environmental Protection Agency (EPA) and the National Weather Service (NWS) has made many Americans more aware of the risks of sunburn and skin cancer from the sun's (UV) radiation.

But did you know UV and other radiation from the sun also can harm your eyes?

Extended exposure to the sun's UV rays has been linked to eye damage, including cataracts, macular degeneration, pingueculae, pterygia and that can cause temporary vision loss.

And new research suggests the sun's high-energy visible (HEV) radiation (also called "blue light") may increase your long-term risk of macular degeneration. People with low blood plasma levels of vitamin C and other antioxidants especially appear at risk of retinal damage from HEV radiation.

Dangers Of Ultraviolet Radiation To Your Eyes

To protect your eyes from harmful solar radiation, sunglasses should block 100 percent of UV rays and also absorb most HEV rays. Frames with a close-fitting style provide the best protection because they limit how much stray sunlight reaches your eyes from above and beyond the periphery of your sunglass lenses.

While many people refer to ultraviolet radiation as UV light, the term technically is incorrect because you cannot see UV rays.

The three categories of invisible high-energy UV rays are:

UVC rays. These are the highest-energy UV rays and potentially could be the most harmful to your eyes and skin. Fortunately, the atmosphere's ozone layer blocks virtually all UVC rays.

But this also means depletion of the ozone layer potentially could allow high-energy UVC rays to reach the earth's surface and cause serious UV-related health problems. UVC rays have wavelengths of 100-280 (nm).

UVB rays. These have slightly longer wavelengths (280-315 nm) and lower energy than UVC rays. These rays are filtered partially by the ozone layer, but some still reach the earth's surface.

In low doses, UVB radiation stimulates the production of (a skin pigment), causing the skin to darken, creating a suntan.

But in higher doses, UVB rays cause sunburn that increases the risk of skin cancer. UVB rays also cause skin discolorations, wrinkles and other signs of premature aging of the skin.

UVA rays. These are closer to visible light rays and have lower energy than UVB and UVC rays. But UVA rays can pass through the and reach the and inside the eye.

Overexposure to UVA radiation has been linked to the development of certain types of cataracts, and research suggests UVA rays may play a role in development of macular degeneration.