Contact lens

A contact lens (also known as a "contact") is a corrective, cosmetic, or sometimes protective lens placed on the cornea of the eye.

Related Topics:
Corrective - Lens - Cornea - Eye

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Contact lenses are available in a number of varieties, including hard and soft. Hard contacts are typically not disposable, while soft contacts often are. Some soft contacts are also known as extended wear lenses. The most commonly used contact lenses today are of the soft variety, invented in 1961 by the Czech chemist Otto Wichterle (1913–1998).

Related Topics:
Extended wear lenses - 1961 - Czech - Otto Wichterle

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Contact lenses (both soft and hard) are made of various types of polymers, the latest containing some variant of silicone hydrogel. Previously, hard contact lenses were made of a polymer known as PMMA. They have since been replaced by rigid gas-permeable (RGP) contact lenses. Many contact lenses are made of hydrophilic (water-absorbing) materials, thereby allowing oxygen to reach the cornea, and make the lens more comfortable to wear.

Related Topics:
Polymer - Hydrogel - PMMA - Hydrophilic

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Heavily tinted contacts are tinted to change the color of the iris, and are used for cosmetic reasons. Some standard contact lenses are slightly tinted in order to make them more visible for handling purposes.

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