contact lens

contact lens, thin plastic lens worn between the eye and eyelid that may be used instead of eyeglasses. Actors, models, and others wear them for appearance, and athletes use them for safety and convenience. Contact lenses may also be used to correct certain abnormalities of the eye that cannot be corrected by regular glasses. A. E. Fick, a Swiss physician, made the first contact lens in 1887. His heavy glass lenses exerted an uncomfortable pressure on the eyeball, covered the entire eye surface, and were difficult to fit. In 1938, the first plastic contact lens was made by Theodore E. Obrig, using a newly discovered methylmethacrylate plastic, known as Plexiglas or Lucite, that could be molded into the proper shape. The major drawback was that a solution placed between the lens and eye had to be changed every few hours, because the wearer's tears could not circulate beneath the lens. In 1950, the corneal contact lens was introduced. It covered only the cornea of the eye, floated on the tears of the wearer, and could be worn all day without difficulty. Recent improvements include flexible lenses that shorten the initial period of adjustment for the wearer and porous lenses that do not have to be removed each day. Today, contact lenses that "breathe" have become popular. They allow oxygen to get to the cornea, preventing blurred vision due to the corneal exhaustion syndrome.

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.

More on contact lens from Fact Monster:

  • Otto Wichterle - Biography of Otto Wichterle, Wichterle’s soft contact lens proved to be less expensive and more comfortable than traditional glass or hard plastic lenses. A significant …
  • LENSES - A lens is a piece of transparent plastic or glass that can make things seem to change size. It works by bending light rays so they appear to come from
  • eyeglasses - eyeglasses eyeglasses or spectacles,instrument or device for aiding and correcting defective sight. ...
  • FORCES AND ENERGY - From the movements of the planets to the energy produced inside atoms, everything that happens in the Universe is ultimately caused by forces. A force
  • Advanced-Level Science Projects: Biology - Advanced-Level Science Projects Biology Advanced-Level Science Projects Biology Do Plants Sweat ...

See more Encyclopedia articles on: Medicine