contact lens

The manufacture of contact lenses is now a long-established part of the plastics industry. What has changed in recent decades is the use of softer plastics that accommodate their shape to that of the eye. This means that special fitting or measurements are no longer required, and lenses can be made so precisely and in such quantities as to be disposable after use.

Lens, made of soft or hard plastic, that is worn in contact with the cornea and conjunctiva of the eye, beneath the eyelid, to correct defective vision. In special circumstances, contact lenses may be used as protective shells or for cosmetic purposes, such as changing eye colour.

The earliest use of contact lenses in the late 19th century was protective, or in the correction of corneal malformation. It was not until the 1930s that simplification of fitting technique by taking eye impressions made general use possible. Recent developments are a type of soft lens that can be worn for lengthy periods without removal, and a disposable soft lens that needs no cleaning but should be discarded after a week of constant wear.