MORE THAN MEETES THE EYE

Sunglasses can do more than make you look cool. They can also protect your eyes from damaging sun rays.

But be careful, local optometrists say. If you don't choose the right sunglasses, you could do your eyes more harm than good.

"The primary reason for wearing sunglasses is to keep out UV rays," said Dr. Jim L. Davis, a Cape Girardeau optometrist. Ultraviolet or "UV" radiation is an invisible part of the electromagnetic spectrum that comes from sunlight.

While studies aren't conclusive, it is suspected that ultraviolet rays can damage the eye, said Dr. Robert Felker, an optometrist at Brost and Associates in Cape Girardeau. Exposure to UV rays may contribute to the formation of cataracts, a clouding of the eye's lens; macular degeneration, where a portion of the retina is destroyed; and damage to the retina and surface of the eye, according to the American Optometric Association.

While research into the damage is still ongoing, Felker said most optometrists recommend sunglasses to be on the safe side, especially for people who work outdoors or on water.

However, both doctors warned that not all sunglasses are created equal.

Not all sunglasses protect against ultraviolet rays, Felker said. And without UV protection, sunglasses can actually expose the retina to more ultraviolet light since dark lenses make the eye's pupils enlarge, letting in more light.

Also, sunglasses that are not of ophthalmic quality, and if they are it will say so on the label, may have distortions in the lenses that can cause eye strain, David said.

According to the American Optometric Association, to provide adequate protection sunglasses should block out 99 to 100 percent of both UV-A and UV-B radiation and screen out 75 to 90 percent of visible light.

Some sunglasses are marked with actual percentages of UV blocked; others say "maximum protection," which is hard to judge. Look for sunglasses with the AOA's Seal of Acceptance or have the UV level tested by an optometrist.

For a quick check to see if the sunglasses screen out enough visible light, put on the sunglasses in the store and look in a mirror. If you still see your eyes, they're probably not dark enough to work effectively.

Sunglasses also should be perfectly matched in color and free of distortion and imperfection, according to AOA. The lens colors that are easiest on the eyes are gray, which doesn't modify colors, or green or brown.

While sunglasses are associated with summer, Felker noted that the sun shines all year long. So he recommends wearing sunglasses year-round.

SUNGLASS PROTECTION

Sunglasses can protect your eyes against the harmful rays of the sun. To provide adequate protection sunglasses should:

* Block out 99 percent 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, with lenses that are gray, green or brown.

Also remember that:

* Contact lenses are now available with a UV blocking feature. However, these contact lenses should not be worn in place of your sunglasses, but do provide additional protection by blocking much of the UV radiation that can seep in from above and below your sunglasses.

* Sunglasses that are worn while you participate in eye hazardous work or sports should be made of 2-millimeter thick polycarbonate.

* Because UV damage is cumulative, children should be encouraged to wear sunglasses beginning in infancy whenever they are out in the sun. Their eyes are most susceptible to UV damage because the eye's lens has not yet begun to cloud.

* Light eyes have less pigmentation and are thus more susceptible to the harmful effects of UV radiation just as lighter skin is.

* Polaroid sunglasses protect you from the glare of the sun. If you wear sunglasses and you squint with your sunglasses on, you are glare sensitive and a Polaroid or mirrored lens would be more appropriate for you.

* Sunglasses that provide side shields are the best at blocking out harmful rays.

* Wearing sunglasses not only keeps the sun from damaging the skin around your eyes, it cuts down on squinting, which helps stave off fine lines and wrinkles around the eyes.

For more information on eye health and eye care visit the American Optometric Association's Web site at http://www.aoanet.org.