Lenses worn directly against the eye, separated from it only by a film of tear fluid. Corneal microlenses cover only the cornea, while haptic lenses cover some of the surrounding sclera as well. Contact lenses are used mainly in place of spectacles, to correct errors of refraction, but also in a protective capacity (see bandage lens). Contact lenses are made of a variety of materials, such as glass, plastic, and silicone; soft gas-permeable lenses have mostly replaced hard Perspex lenses.
Subjects: Medicine and Health.