Sunglass side shields protect your eyes from glare and bright light, and they're a terrific fashion accessory. But they also offer eye protection, shielding the eye from potentially damaging ultraviolet (UV) light. Experts say that even just short periods of exposure to UV radiation can cause eye damage over a long period of time, just from going out every day without eye protection.

The most common UV damage that eye doctors see are melanomas on the eye lids, acute eye pain, cataracts, and degenerative changes to the eye. In fact, studies have found that people who don't wear sunglasses, exposing their eyes to UV light for hours every day, are three times at risk of developing cataracts. Fortunately, wearing a hat with a brim or sunglasses when going out on sunny days can do a lot to help protect the eyes from UV radiation.

For those who want to protect their eyes even further, there are sunglasses that come with side shields, which block UV light. You've undoubtedly seen these shields on the heavy dark glasses worn by older people who already have cataracts and people who have just come from an eye appointment. But sunglass side shields available for anyone who wants to wear them, either as part of some sunglasses design or as add-ons that can be attached to your existing sunglasses.

For people who wear sunglasses while playing sports or engaging in other outdoor activities, side shields offer an additional level of protection from sand, debris and other material that could get into the eye, and many shields have vents so that the lenses of the sunglasses don;'t fog up.

When buying a pair of sunglass side shields, you get what you pay for. Or, rather, you get what you don't pay for - inexpensive sunglasses are usually not made with optical-quality glass like prescription glasses, and can cause sight problems down the road from peering through cheap glass or plastic lenses. And you should look at what the lenses are made from - for complete UV protection, the lenses should be crafted from polycarbonate or from plastic with a dye that absorbs UV radiation.

Polycarbonate plastic absorbs all UV radiation, while prescription-quality glass or plastic lenses absorb approximately 85 percent of UV radiation. But even with lenses that absorb 100 percent of UV radiation, light still can get to the eye from the tops or sides of the sunglasses, which is why side shields are an excellent idea for anyone, no matter what your age or how often you go out in the sun.

Dean Iggo is the webmaster of a contact lenses review site where you can find reviews and information on everything from toric contact lenses to LASIK eye surgery and more..