June 24, 2004

LASIK Reduces Supply of Usable Donor Corneas

LASIK may hurt donor corneas

Albuquerque Journal (New Mexico)
Jackie Jadrnak Journal Staff Writer

* Doctor says weakened spot may rip during removal for transplant

If you have LASIK surgery to correct your eyesight, a little semicircular line, a sliver of a healed spot, is left behind on your cornea.

It's not a big deal. You can function perfectly well with it there.

But it could make a difference if you donate your corneas for a transplant after you die.

When the corneas are removed and prepared for the transplant, the procedure can cause that weakened spot to rip apart, according to Dr. V. Vinod Mootha, assistant professor of ophthalmology at the University of New Mexico.

"The flap can come loose" during a transplantation, he said. "It's not the end of the world ... but it's not ideal."

A surgeon can stitch the flap back down and continue with the transplant, he said. But, with the supply of corneas actually exceeding the demand for transplants, people in eye banks prefer to separate corneas that had LASIK out of the pool for transplants, said Mootha, who is medical director for the New Mexico Lions Club Eye Bank.

He and his research colleagues may have come up with an approach to screen those donated corneas.

In an article published in the May issue of Archives of Ophthalmology, the research team reported that they were able to identify 23 of 26 corneas (88 percent) that had undergone a LASIK procedure by using specular microscopy. That microscope, which uses reflected light, revealed bright particles in the corneas that had the laser surgery. Those particles -- keratocytes -- may be produced as part of the healing process, Mootha said.

Only one of the 26 corneas that did not have LASIK showed those particles.

In comparison, examination with a slitlamp microscope -- similar to one used in many clinical eye exams -- revealed an obvious flap edge in barely half of the corneas that had them, he said. "Sometimes it's a little subtle," Mootha noted.

Eye banks usually have both microscopes on hand, he said. The specular microscope usually is used to study the innermost layer of the cornea to make sure it has appropriate density of cells, he said.

An Albuquerque company is developing a computer-based system that may use discoveries from this research to produce computer screening of donor corneas, he added.

"This is the largest study to look at human corneas that have had successful LASIK surgery," Mootha said. "It shows they tolerate the surgery well."

About 50,000 to 60,000 corneas are donated nationwide each year, he said. About 40,000 cornea transplant operations are performed each year, with the remainder of the corneas either used for research or shipped to other countries, he said.

The most common condition to cause someone to need a transplant is keratoconus, in which a person's cornea is cone-shaped instead of spherical, according to Mootha.

Fuchs' dystrophy, in which the inner layer of the cornea is weak and swollen, is another condition that can create a need for a new cornea, he said.

Cornea transplants have an 80 percent success rate and last for about 10 or 15 years, he said. After that time, people might need a second transplant, he added.

Mootha said he doesn't want to discourage people who have had LASIK from donating their corneas. The tissues still can be useful in research, he said.

It would be helpful, though, if their family members could inform someone when the corneas are being harvested that they have been subject to laser surgery, Mootha said.

Posted by Admin at June 24, 2004 02:27 AM