Artificial cornea ideal solution for some

July 1, 2008

The use of an artificial cornea in patients who have experienced multiple immunologic graft rejections is more likely to result in good-quality vision than is performing another corneal transplant.

The use of an artificial cornea in patients who have experienced multiple immunologic graft rejections is more likely to result in good-quality vision than is performing another corneal transplant, said Michael W. Belin, MD, Albany Medical College, Albany, New York, US.

He provided an update of results of an ongoing international, multicentre study of a proprietary device (Boston Keratoprosthesis; Massachusetts Eye & Ear Infirmary) involving 250 eyes. Dr Belin said that he has been using the device for about five years.

“The major advantage is that, when we look at the survivability of a graft after a second failed graft, the rate of retention of that transplant clarity drops significantly,” he said. “While the success rate on primary grafts is very high, with failure at maybe 10% or less, once we get to two prior grafts, the rejection rate increases to nearly 40%.

“Statistically, patients do much better with a keratoprosthesis than a third, fourth, or fifth transplant, assuming that their cornea is relatively non-vascularized and that they have a reasonable ocular surface,” he said. Visual rehabilitation is faster with the device than with repeated keratoplasty, he added, because astigmatism is not associated with it.

Potential drawbacks of implanting an artificial cornea are similar to those associated with any transplant, Dr Belin said. “Any transplant, particularly repeat transplants, have an increased risk of inducing glaucoma or a pressure problem, and it’s conceivable that the donor rim can melt as a transplant would melt,” he said. “But the prosthesis is very well-tolerated by the eye.”

The multicentre study has demonstrated a graft survival rate of more than 95%, Dr Belin said, “and if we look at the subset of just patients with immunologic graft rejection, not ocular surface disease, the rate increases to about 98%.”