 The five-year transplant success rate was the same -- 86 percent --
for transplants performed with corneas from donors ages 12-65 years
and from donors ages 66-75, said the study published in the April
issue of Ophthalmology. The cornea, 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,
according to the study authors, recent changes in U.S. Food and Drug
Administration regulations will likely cause a decrease in the
supply of donated corneas. These new regulations that took effect in
June 2007 require additional screening and testing of potential
donors for contagious diseases, registration of eye banks, more
detailed records and labels, and stricter quarantine procedures.
"With the expected decrease in the pool of eligible cornea donors
in the United States and the existing shortage of corneal tissue
internationally, it is encouraging that we now have scientific
evidence showing that older corneas can be used reliably in corneal
transplantations," said Elias A. Zerhouni, M.D., director of the
National Institutes of Health.
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.
"This new research has come at a good time," said Paul A.
Sieving, M.D., Ph.D., director of the National Eye Institute. "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."
"Surgeons and patients now have scientific evidence that older
donor corneas are suitable for transplantation," said Edward J.
Holland, M.D., professor of ophthalmology at the University of
Cincinnati, director of the Cornea Service at the Cincinnati Eye
Institute and co-chair of the study. "Further, when corneas are
readily available, transplant procedures can be scheduled more
efficiently, allowing both surgeons and patients to plan for them."
The Cornea Donor Study, which was coordinated by the Jaeb Center
for Health Research in Tampa, Fla., is a prospective cohort study
conducted with 1,101 participants enrolled by 105 surgeons at 80
sites across the United States. A prospective cohort study is one in
which health outcomes in a group of participants are monitored over
the duration of the study. 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. 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.
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In a secondary study, the researchers examined the fate of the
corneas' endothelial cells. These are 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."
"The CDS is a landmark study," added study co-chair Mark J.
Mannis, M.D., professor and chair of the Department of Ophthalmology
at the University of California, Davis. "It is the largest study of
its type on corneal transplantation ever done. Its size and
five-year patient follow-up, along with a simple trial design, have
provided us with clear and important insights into contemporary
transplantation."
Overall, the demand for organs and tissue is greater than the
supply available for transplantation. The U.S. Department of Health
and Human Services' Health Resources and Services Administration
oversees the organ transplantation program that is responsible for
developing strategies and administering programs to promote organ
and tissue donation. For more information, go to
www.organdonor.gov.
Additional support for the Cornea Donor Study was provided by Eye
Bank Association of America, Bausch & Lomb Inc., Tissue Banks
International, Vision Share Inc., San Diego Eye Bank, The Cornea
Society, Katena Products Inc., ViroMed Laboratories Inc., Midwest
Eye-Banks (Michigan Eye-Bank, Illinois Eye-Bank), Konan Medical
Corporation, Eye Bank for Sight Restoration, SightLife, Sight
Society of Northeastern New York (Lions Eye Bank of Albany), and
Lions Eye Bank of Oregon.
The National Eye Institute is one of the National Institutes of
Health and is the federal government's lead agency for vision
research that leads to sight-saving treatments and plays a key role
in reducing visual impairment and blindness. For more information,
visit www.nei.nih.gov.
The National Institutes of Health, the nation's medical research
agency, includes 27 institutes and centers and is a component of the
U.S. Department of Health and Human Services. It is the primary
federal agency for conducting and supporting basic, clinical and
translational medical research, and it investigates the causes,
treatments and cures for both common and rare diseases. For more
information, visit www.nih.gov.
[Text from file received from
National Eye Institute]
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