Modern contact lenses are thin corrective pieces of eyewear made of plastic. Because they float on a thin film of tears and cover the cornea--the transparent tissue covering the pupil and the iris--they offer the benefits of near invisibility, unimpaired side vision, and ease of wear.

The first contact lenses were made by Adolf Fick in 1887 for the purpose of correcting irregular astigmatism. Like eyeglasses, they were comprised of glass. In 1912, Carl Zeiss (1816-1888) also designed glass lenses. Then, in 1938, Obrig and Muller developed the first hard plastic lenses ( scleral, or haptic, lenses that virtually covered the front of the eyeball). Although optically inferior to glass, plastic proved considerably lighter and more comfortable to wear. Such contact lenses were prevalent until the 1950s; they required an impression of the eyeball to mold the lenses.

In 1948, Kevin Touhy designed plasticcorneallenses, which were decidedly smaller than...