Beware! Regardless of the season or whether it's sunny or cloudy, everyday your eyes are exposed to invisible, damaging UV radiation. In the same way UV rays damage the skin, they also damage the lens and retina of the eyes. Furthermore, just as people with fair skin burn more easily, people with lighter color eyes can sustain damage more quickly to their eyes. Unfortunately, this damage is cumulative and cannot be reversed. If you don't protect your eyes the risk for cataracts, macular degeneration, and skin cancer and other disorders increases. In some cases these diseases can even result in blindness. Fortunately, these devastating diseases can be prevented by wearing sunglasses.

Four types of light can damage your eyes. These are UVC, UVB, UVA, and HEV rays. .

• UVC rays (100-280 nm) have the highest energy and the abiity to do the most damage. Fortunately, almost all of these rays are blocked by the ozone layer. However, with the depletion of the ozone, these rays could cause more damage in the future.
• UVB rays have less energy than UVC rays. These rays can cause photokeratitis.
• UVA rays (280-315 nm) have less energy than UVB rays. However, they can pass through the cornea and reach the lens and retina. These rays are linked to an increase in cataracts and macular degneration.
• HEV rays (400-500 nm) have the least amount of energy between the four. These rays can deeply penetrate the eye and damage the retina. Research has shown people with low blood plasma levels of vitamin C and antioxidants are more prone to HEV radiation damage.

In addition to the type of rays, there are risk factors too. UV levels are greatest near the equator and at higher altitudes. Both UV and HEV rays are greater between 10AM and 2PM and in wide open spaces. When reflective surfaces are present such snow, sand, and pavement, the levels are even greater. However, urban settings reduce the levels because tall buildings shade the reflective streets.

Certain medications can also increase your eye's sensitivity to light. These medications include tetracycline, birth control pills, sulfa drugs, diruretics, and tranquilizers.

Sun damage can cause several eye disorders. Photokeratitis, pinguelculaie, and pteryguim can all be caused by excessive exposure to the sun.  Your risk for cataracts, macular degeneration, and cancer of the surrounding skin of the eye also increase.

• Photokeratitis is a burn on the cornea. Also called snowblindness, this condition is caused by UVB radiation from the reflection of snow at high altitudes.
• Pteryguim are small or large benign growths in which the conjuntiva grows into the cornea. . Although the exact cause is unknown, it is associated with excessive exposure to wind, sunlight, or sand. Although most people do not experience any symptoms, a large growth may cause astigmatism.
• Pingueculum is a yellowish patch on the white or sclera of the eye. It may feel like there is something in the eye.
• Cataracts occur when the protien of the lens clumps together and causes cloudiness.
• Macular Degeneration is caused by the degeneration of the macula, and it affects central vision.

Considering the sun's damaging effects on vision, what features should one look for when purchasing sunglasses?

• You get what you pay for. The cost of manufacturing sunglasses that meet or exceed the minimum safety standards are a major factor in the cost of manufacturing sunglasses.
• Choose sunglasses that filter out at least 99% of the UVB rays and 95% of UVA rays. Never assume they are good sunglasses. Check the label for the sun protection rating.
• Contrary to what some people think, the color and darkness of the lens does not protect against UV light. . However, it does offer protection from HEV or blue light. Colors that do well at blocking blue light are bronze, copper, and reddish-brown.
• Bigger lenses and wrap-around lenes offer more protection. Furthermore, look for lenses that fit close to the eye.
• Wrap-around lenses offer more protection.
• If you participate in sports, you may want to consider lenses made out of polycarbonate or Trivex. They are more impact resistant.
• Lenses that are too dark can cause the pupils to dilate and allow uva radiation to damage the lens and retina.

Although there are contact lenses that filter out UV rays too, they don't block out as many rays as sunglasses. Therefore, it is better to wear sunglasses anyway. Wearing a wide-brimmed hat in addition to sunglasses can also help protect your eyes. Furthermore, when your swimming, wearing goggles can also help protect your eyes from the sun and bacteria. Since UV rays are still present during the fall and winter, you should still wear sunglasses.

You only recieve one pair of eyes. Since sun damage can occur regardless of the season or weather, and the effects are cumulative, wearing sunglasses everyday is important.  Furthermore, since children usually spend more time outdoors, and their eyes are more vulnerable to damaging rays, experts believe as much as 80% of our exposure to UV rays occurs by the age of 18. Considering this information, every member of your family should have a quality pair of sunglasses.