As many individuals find direct sunlight too bright and uncomfortable on the eyes, sunglasses are a wonderful visual aid to prevent blinding light from reaching the eyes. Sunglasses work best in outdoor activities, such as flying, riding, skiing and motorcycling. Doctors recommend to wear sunglasses whenever outside to protect our eyes from ultraviolet radiation. This can lead to the serious development of cataract. As a desire to mask their identity, celebrities and film stars wear sunglasses. They can also wear them due to the production lighting being more forceful than natural light. Sunglasses-namely on the beach-have been a popular fashion statement since the 1950s.



The color of the lens can actually vary by fashion, purpose and style. Green, yellow, brown or gray is recommended for general use to avoid or limit color distortion. This could be dangerous when driving an automobile. Gray lenses on sunglasses are considered neutral due to the fact they don't augment contrast or even distort colors. Green and brown lenses cause quite a limited color distortion, but have properties which are contrast-enhancing properties. The red lenses are good for medium and lower light conditions. This is due to the fact that they are good at enhancing contrast, but creates color distortion. Yellow lenses have the best contrast enhancement for depth perception. However, they do cause color distortion. Sunglasses with yellow lenses are usually used by avid golfers and shooters for the contrast enhancement, as well as depth perception properties. Other colors, such as purple and blue, offer no true benefits-they are chiefly cosmetic. Some sunglasses with the interchangeable lens have clear lenses as an option to protect eyes during low light or nocturnal activities. "Blue blocking" or tinted lenses of amber are a result of heated debates in regards to the protective effect.

A few top-of-the-line model sunglasses-like Costa Del mar-have polarized lenses to diminish glare created by light reflected from polarizing surfaces, such as water and polarized skylight. This is normally useful when fishing-the ability to see under the surface of water is impertinent. Some sunglasses use a gradation where the top of lenses is darker, as the bottom is transparent. Sometimes, a mirrored coating is applied to the lens. The mirrored coating reflects some of the light when it hits the lens of the sunglasses before it's transmitted through the lens. This makes the situation useful in very bright conditions. The mirrored coatings can be manufactured in any color for fashion and styling purposes.

Frames on sunglasses can be made to hold the lenses in assorted ways. There are a few common styles: full frame to go all around; half frame to go around only half the lens; and frameless, where the ear stems are attached to the lenses directly.