|Older Corneas Suitable for Transplantation,
Could Expand Donor Pool Significantly
The age pool of corneas for transplant should be expanded to include
donors up to 75 years of age, based on findings from a study funded
by the National Eye Institute (NEI), one of the National Institutes
of Health (NIH). Corneal transplants using tissue from older donors
have similar rates of survival to those using tissue from younger
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, 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 (FDA) 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
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 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."
"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 (CDS), 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.
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
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
(HRSA) 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 (NEI) is one of the National Institutes
of Health (NIH) 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 the NEI Website at www.nei.nih.gov/.
The National Institutes of Health (NIH) — 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 about NIH and
its programs, visit www.nih.gov.