As the holiday season approaches and we prepare to head for beaches and swimming pools, most of us are aware of the danger of the sun’s ultraviolet (UV) radiation on our skins. But there is also a risk of damage to our eyes. Extended exposure to the sun's UV rays has been linked to conditions including cataracts, macular degeneration, and others.

While many people refer to ultraviolet radiation as UV light, this is technically incorrect because we cannot see UV rays. There are three categories of UV rays: UVC rays are the most harmful, but fortunately the atmosphere’s ozone layer blocks virtually all of these; UVB rays in low doses stimulate the production of melanin creating a suntan, but in higher doses cause sunburn and premature aging of the skin, and are partially filtered by the ozone layer; UVA rays have the lowest energy but can pass through the cornea, reaching the lens and retina.

Outdoor Risk Factors

Anyone who spends time outdoors is at risk for eye problems from UV radiation, but this exposure depends on a number of factors.

Geographic location. UV levels are greater in tropical areas; the further you are from the equator, the smaller your risk.

Altitude. UV levels are greater at higher altitudes.

Time of day. UV levels are greater when the sun is high in the sky, typically from 10 a.m. to 2 p.m.

Setting. UV levels are greater in wide open spaces, especially when highly reflective surfaces are present, like snow and sand. UV exposure is less likely in urban settings, where tall buildings shade the streets.

Medications. Certain medications can increase your body's sensitivity to UV radiation.

Your risk of UV exposure can be quite high even on hazy or overcast days. This is because UV is invisible radiation, not visible light, and can penetrate clouds.

Children and UV Protection

The risk of damage to our eyes and skin from solar UV radiation is cumulative, so the more time we spend in the sun throughout our lifetime, the more the danger grows. With this in mind, it is especially important for children’s eyes to be protected from the sun. Make sure your children's eyes are protected from the sun with good quality sunglasses. Also, encourage your child to wear a hat on sunny days to further reduce UV exposure.

Sunglasses That Protect Your Eyes From UV Rays

To best protect your eyes from the sun's harmful UV rays, always wear good quality sunglasses when you are outdoors.

Not all sunglasses block 100% of UV rays, but it is possible to measure the amount of visible light and UV radiation your lenses block. Ask your optometrist about this.

Sunglasses with large lenses or a close-fitting wraparound style help to protect the delicate skin around the eyes.

The amount of UV protection sunglasses provide is unrelated to the color and darkness of the lenses. A light amber-colored lens can provide the same UV protection as a dark gray lens.

In addition to sunglasses, wearing a wide-brimmed hat on sunny days can reduce your eyes' exposure to UV rays by up to 50 percent.

Remember to wear sunglasses even when you're in the shade. Although shade reduces UV exposure to some degree, your eyes will still be exposed to UV rays reflected from buildings, roadways and other surfaces.

Even if your contact lenses block UV rays, you still need sunglasses. UV-blocking contacts shield only the part of your eye under the lens, and can still damage areas of the eye not covered by the lens.

If you have dark skin and eyes, you still need to wear sunglasses. Although your dark skin may give you some protection, your risk of eye damage from UV rays is the same as that of someone with fair skin.