Short information about Contact lens
A contact lens (as well known as a "contact") is a corrective, cosmetic, or at times protective lens placed on the cornea of the eye.
The Contact lenses are obtainable in a number of varieties, together with hard and soft. Hard contacts are characteristically not disposable, while soft contacts often are. Few soft contacts are as well known as extended wear lenses. The most normally used contact lenses nowadays are of the soft variety, made-up in 1961 by the Czech chemist Otto Wichterle (1913–1998).
The Contact lenses (both soft and hard) are made of a range of types of polymers, the most recent containing some variant of silicone hydrogel. Formerly, hard contact lenses were made of a polymer recognized as PMMA. They have since been replaced by rigid gas-permeable (RGP) contact lenses. Numerous contact lenses are made of hydrophilic (water-absorbing) materials, in that way allowing oxygen to reach the cornea, and make the lens easier to wear. Heavily tinted contacts are tinted to adjust or to alter the color of the iris, and are used for cosmetic reasons. Some ordinary contact lenses are somewhat tinted to make them more noticeable for handling purposes.