Sunglasses are not just a fashion accessory. Exotic lens colors may be stylish, but gray because it absorbs all colors about equally diminishes color perception the least. Green is second-best.
Sunglasses should block 99-100% of both kinds of ultraviolet (UV) radiation: UVA and UVB. Look for this information on a label or hangtag. If glare is a problem, polarized lenses are a good choice. "Mirror" lenses, the type favored by skiers, also help to decrease glare, because they screen out more light than do tinted lenses.
According to the American Optometry Association, quality nonprescription sunglasses as those with lenses that are free of distortion, imperfection, and mismatching of color and absorptive power. To check the refractive quality of a lens, hold the glasses at arm's length and look through each lens at a straight line or edge in the distance. If the line curves or appears distorted when you move the lens back and forth, the lens is optically imperfect. Also determine whether the color of the lenses is uniform.
The Food and Drug Administration defines sunglasses as medical devices. They are therefore subject to regulatory requirements for safety and effectiveness, including an impact-resistance standard. Thus, you'll get an impact-resistant product whether you choose glass or plastic lenses.
This article is an abbreviated excerpt from the new ACSH booklet Health and Safety Tips for Your Summer Vacation.
(From Priorities, Vol. 9, No. 2)