EfluxMedia

According to the findings of a new study funded by the National Eye Institute (NEI) the age pool of corneas for transplant should be expanded to include donors up to 75 years of age. The cornea, a clear dome-shaped surface that covers the front of the eye, offers protection and helps focus light entering the eye.

The study, called the Cornea Donor Study (CDS) was coordinated by the Jaeb Center for Health Research in Tampa, Fla., and it was conducted with 1,101 participants enrolled by 105 surgeons at 80 sites across the United States.

According to the researchers, the five-year transplant success rate was the same - 86 percent - for transplants performed with corneas from donors ages 12 to 65 years and from donors ages 66 to 75. The study was published in the April issue of Ophthalmology.

"This new research has come at a good time," said Paul A. Sieving, M.D., Ph.D., director of NEI. "The pressure on eye banks to provide corneas is increasing. The results of this study will expand the available donor pool and should persuade surgeons to use corneas from older donors. These changes will greatly benefit the growing number of individuals who need corneal transplants."

The participants, who were between 40 and 80 years of age, were chosen for the study if they were in need of a corneal transplant for a corneal disease that put them at moderate risk for clouding of the transplanted cornea. Donor corneas were provided by 43 participating eye banks. All donor corneas met the Eye Bank Association of America's standards for human corneal transplantation and were consistent with eye banks' tissue ratings of good to excellent quality. After the transplant surgery, the participants were followed for five years. The transplant was considered a failure if a repeat corneal transplant was required or if the cornea was cloudy for at least three months.

In another study, the scientists examined the fate of the corneas' endothelial cells, the flat cells that live on the back of transplanted corneas and are essential for keeping the cornea clear.

"Though there was cell loss in both age groups, in 86 percent of the cases the corneas remained clear after five years," said Jonathan H. Lass, M.D., professor and chair of the Department of Ophthalmology and Visual Sciences at Case Western Reserve University and University Hospitals Case Medical Center, and medical director of the study's endothelial image reading center. "These findings suggest the opportunity for further research to continue to perfect corneal transplants."

According to NEI, more than 33,000 corneal transplants are performed each year in the United States and in the past years the availability of donor cornea has been adequate. But the recent changes in U.S. Food and Drug Administration (FDA) regulations will likely cause a decrease in the supply of donated corneas. In addition, many eye banks previously set the age limit for donors at 65 years or younger because some surgeons have been reluctant to use older corneas. According to the study authors, their findings could lessen these restrictive policies. They estimate that use of older donor tissue could expand the donor pool by as much as 20 percent to 35 percent.