Sunglasses: Joe Cool, Joe Smart

For some, sunglasses are a fashion statement. For others, they are a safety feature.

Most cells in our body replenish themselves, but the lens in our eye is a notable exception. The cells of the lens of the eye cannot replace themselves. Exposure to the sun's ultraviolet rays (UV) occurs over a lifetime, and because the body cannot undo the damage that occurs over a lifetime, infants and children should have their eyes protected as well.

Recent studies indicate that the risk of cataracts (the gradual clouding of the lens of the eye) is tripled by long-term exposure to the sun's UV rays. In addition to the lens, the retina also may be damaged by UV rays. People with macular degeneration and other retinal disease need to take special care.

"Most people wear sunglasses to reduce glare," says Thomas Oetting, MD, UI Health Care ophthalmologist. "Even more important is the long-term UV protection the right sunglasses provide. Sunglasses that block 100 percent of the sun's UV radiation may slow the development of cataracts. Check the tag on sunglasses to see how much protection they afford you before you buy them."

Not all sunglasses are created equal. Price and degree of darkness of the lenses may not be good indicators of the UV protection. Unless your sunglasses provide UV protection, they may do more harm than good. Dark lenses without UV protection may cause your pupils to dilate allowing even more UV rays into the eye.

Wear sunglasses when you go outside and be both cool and smart at the same time.

University of Iowa Health Science Relations, Tom Oetting, MD