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 this procedure, invented by an American named Kelman in 1976, an ultrasonic device actually emulsifies or breaks the lens into tiny fragments so that it can be aspirated from the eye. A new intraocular lens made of plastic is inserted and the incision closed with tiny sutures. Plastic lenses were first invented in 1952 by an English physician, Harold Ridley. After the plastic lens is transplanted, the patient is able to see. The patient may be fitted for special glasses or contact lenses.
Cataract surgery has a long history. It was mentioned in the code of Hammurabi, the Babylonian king who lived 4000 years ago. The first known cataract operation to extract a clouded lens was performed by J. Daviel, a Frenchman, in 1748. Another well-known English surgeon, William Cheselden (1688-1752), restored sight to a man born blind.
In 1905 Austrian physician Eduard Zirm performed the first known cornea transplant by transplanting the cornea of one person into the eye of a blind person. Basing his work on Zirm, Doctor Elschwig of Prague also successfully performed a cornea transplant in 1914. Since 1944, eye banks have been established in many places around the world where donated eyes may be stored in order to be used in such transplants.
In 1961, an American physician, Irving S. Cooper, began using a freezing technique known as cryosurgery to freeze and destroy damaged tissue. He first used cryosurgery on damaged brain tissue of Parkinson's disease patients. Now it is successfully used to remove cataracts from the lens of the eye. In 1979, the first laser eye surgery was performed using an ultra-rapid pulsated Yag laser. Done by Professor Daniele Aron-Rosa, laser eye surgery allows surgery without having to cut the eye. Since that time laser surgery has successfully been used on corneas and detached retinas. For cataracts, it is used primarily to make a clear opening in the posterior capsule if it turns cloudy after the original cataract operation.
Further advances in cataract surgery have made it a routine and, for the most part, outpatient therapy. For example, anesthetic eye drops have been developed to replace the standard injection method, thus eliminating complications sometimes associated with injections. Advanced surgical techniques have also led to smaller and smaller incisions that no long require sutures. These small incisions, in turn, are leading surgeons to concentrate more on surgical techniques that will restore multifocal vision in cataract patients, thus reducing their dependency on eye glasses after surgery.
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