Just as we use sunscreen to keep the sun's UV rays from harming our skin, UV treatment in eyeglass lenses block those same rays from damaging our eyes. Overexposure to ultraviolet light is thought to be a cause of cataracts, retinal damage and other eye problems.

An ultraviolet treatment is simple and quick to apply to most plastic eyeglass lenses, and it does not change the appearance of the lenses. The exception is polycarbonate lenses, which don't need UV treatment because it is an inherent property of the material.

Several of the most serious eye problems can be linked to one cause: UV light. UV is separated into two categories based on the frequency and wavelength of the light: UV-A and UV-B.

As a natural protection mechanism, the cornea of your eye absorbs all of the UV-B and most of the UV-A light. But some of the UV-A light reaches the lens of the eye, and over time this absorption can lead to cataracts. The small amount of UV-A which gets past your cornea and reaches the retina, can eventually lead to macular degeneration, the leading cause of blindness in people older than age 65. Intense and prolonged exposure to UV radiation can cause either cancer of the eye or photokeratitis, which is basically sunburn on your retina.

Proper UV coating on your sunglasses can eliminate UV radiation, and you should check to make sure that your sunglasses filter out 100 percent of both types of UV rays.