New artificial cornea shows promise.

New artificial cornea shows promise

The first vision-restoring transplant of a new, soft plastic cornea on a human patient was reported last month. The artificial cornea is designed to replace the normally transparent tissue that covers the front of the eye following corneal injury or disease. Its developers say that the clear plastic disc holds promise for many of the thousands of people for whom live corneal transplants are inappropriate or unavailable.

More than 28,000 corneal transplants were performed in the United States in 1986 -- more than all other organ transplants combined. But because of a shortage of donated corneas, another 5,000 patients remain on waiting lists each year, spurring interest in the development of plastic replacements.

The new artificial cornea, developed by Delmar Caldwell and Jean Jacob-LaBarre at the Tulane University Medical School in New Orleans, shows signs of having overcome many of the difficulties that have plagued previous, less elastic corneal prostheses. Hard plastic corneas are often expelled from the eye because of the tremendous shearing pressure exerted on them by the eyelids during blinking. The new device is flexible and made of two kinds of plastic; the center area is smooth and transparent, while the surrounding opaque "skirt" is designed to accommodate new cell growth from surrounding eye tissue. It features radial spokes that are stitched into the eye to help hold it in place.

The first human recipient to have his vision restored with the plastic cornea is "doing great," says Caldwell, who performed the surgery Dec. 9. He says that because the device requires no outside source of moisture, it may prove especially useful in patients who, due to severe injury or burns, cannot produce tears. And if future trials are successful, he says, the device "could very easily replace corneal transplants altogether."