Cataract surgery involves removing cataracts from the lens of an eye or removing the lens altogether and replacing it with new lens. Cataracts are spots on the lens that may cloud the lens, causing a blurring of vision and eventually blindness. The lens of the eye helps to focus light. Light from an object first strikes the transparent covering of the eyeball, the cornea. Then the light passes through the lens, which bends the light rays enough so that they focus on the back of the eye, the retina. Sometimes with age or due to other conditions, cataracts form and light can no longer pass through the affected part of the lens. To correct the problem, several alternative procedures may be used.

A surgical procedure called an introcapsular extraction involves removing the entire lens through a cut made along the top edge of the cornea. In...