April 1, 2008
Older corneas are suitable for transplantation, NEI study says
U-M Kellogg Eye Center reports that donor pool could expand significantly
Alan Sugar, M.D.
ANN ARBOR, MI - The pool of cornea transplant donors — often limited to those 65 years of age and younger—should be expanded to include donors up to 75 years of age. This finding emerged in a nationwide study that included the University of Michigan Kellogg Eye Center as one of the study sites.
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, according to a study by the National Eye Institute (NEI) of the National Institutes of Health and published in the April issue of Ophthalmology. The cornea is a clear dome-shaped surface that covers the front of the eye, offers protection, and helps focus light entering the eye.
The availability of donor corneas has been adequate for the past 10 years in the United States, where more than 33,000 corneal transplants are performed each year. However, recent changes in U.S. Food and Drug Administration (FDA) regulations will likely cause a decrease in the supply of donated corneas. These new regulations took effect in June 2007 and require additional screening and testing of potential donors for contagious diseases, registration of eye banks, more detailed records and labels, and stricter quarantine procedures.
"This pivotal study on transplantation indicates that corneas from older individuals are just as successful as those from younger donors," said Alan Sugar, M.D., a nationally-known cornea surgeon at the U-M Kellogg Eye Center. "One result of the study is an expanded pool of cornea donors," said Dr. Sugar, but he notes that the study will also help surgeons learn more about the procedure itself. "The study team is analyzing additional data that will help us understand more fully the factors involved in a successful cornea transplant," he said. Dr. Sugar noted that the Cornea Donor Study will continue for another five years, allowing more time to follow patients and interpret data.
The U-M Kellogg Eye Center is one of 80 sites that participated in the Cornea Donor Study, which included more than 1,101 participants and 105 surgeons from across the United States. Participants were between 40 and 80 years of age and 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. 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.
Donor corneas were provided by 43 participating eye banks, with the Midwest Eye-Bank being the leading supplier of tissue. All donor corneas met Eye Bank Association of America standards for human corneal transplantation and were consistent with eye banks’ tissue ratings of good to excellent quality.
"The pressure on eye banks to provide corneas is increasing," said Paul A. Sieving, M.D., Ph.D., director of NEI. "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."
For years, the U-M Kellogg Eye Center has played a significant role in corneal transplantation. Kellogg ophthalmologists helped to establish the Michigan Eye-Bank in 1957, and it resided in the Kellogg Eye Center until 2006. Today, Cornea Service faculty at Kellogg are pioneering the use of the femtosecond (ultra-fast) laser in cornea transplantation. Kellogg ophthalmologists discovered this laser’s potential for refractive surgery and other eye procedures in the early 1990s.
The Cornea Service at the U-M Kellogg Eye Center serves a broad population nationally and in southeastern Michigan and is known for its expertise in various forms of cornea transplantation, refractive surgery, and cataract surgery.
Overall, the demand for organs and tissue is greater than the supply available for transplantation.Michigan residents who wish to become donors can register at www.giftoflifemichigan.org or at any Secretary of State Branch office. More information is available from the Michigan Eye-Bank at www.michiganeyebank.org.
Written by Betsy Nisbet