Ultraviolet (UV) protection is another beneficial lens treatment that is invisible to the naked eye. Just like sunscreen is used to keep the sun's harmful UV rays from damaging our skin, UV treatment in eyeglass lenses prevents those same rays from damaging our eyes. The eyes being overexposed to ultraviolet light is thought to be a cause of cataracts, retinal damage, and other serious eye problems. The application of an ultraviolet treatment is simple and quick to apply to most plastic eyeglass lenses without affecting the appearance of the lenses. Some lenses which include high index and Trivex don't need a UV treatment because it is an inherent property of the lens material.