As you pull out your summer wardrobe and go looking for a pair of sunglasses, here are some things to consider. The sun emits light of all different wavelengths. The most dangerous wavelengths to the eye are the ultraviolet (UV) rays. These rays are capable of burning the cornea, a condition called photokeratitis. This can be very painful as the cornea is especially sensitive. The UV rays are also thought to be related to cataract development and age-related macular degeneration. The eyelids can be harmed when sunburned or develop skin cancer.
Here are some tips for purchasing sunglasses. Most importantly, make sure that the label says that the sunglasses will protect you from 99-100% UVA and UVB rays. These are two different forms of ultraviolet light, both of which can cause damage to the eyes. If the label does not specify both of these, the sunglasses will not provide adequate protection. Choose sunglasses that fit as close to the face as possible. Consider wrap around styles as they provide better protection. Neither the color of the lenses, nor the price of the glasses, is important. Many people prefer dark tints on the sunglasses to increase eye comfort in bright light; however, it is possible to have UV coatings even on clear lenses. Polarized lenses also may provide added comfort to people who spend time surrounded by horizontal surfaces such as roofers, truck drivers, or fishermen. This is because polarized lenses block the light rays that are reflected from these surfaces while allowing many of the direct rays to penetrate through the lens.
