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DURHAM, N.C. -- A new technique being used in some types of
cornea transplants means a shorter recovery time for patients
and may lead to even better vision after surgery. The advance
could make it possible for eye specialists to offer cornea
transplants to visually impaired patients in Third World
countries and other areas where such procedures have previously
been impractical, according to researchers at Duke University Eye Center.

The technique, known as Descemet's Stripping Endothelial
Keratoplasty (DSEK), allows surgeons to remove a much smaller
portion of the patient's cornea compared with older methods of
transplantation. Standard human cornea transplants involve
removal of the full thickness of the patient's cornea and
replacement with full thickness donor tissue. In the newer
method, surgeons remove only the diseased layer of cells at the
back of the cornea and replace it with a similar amount of
donor tissue. Doing so helps to retain the structural integrity
and mechanical strength of the eye, and typically means a
shorter recovery period for the patient.

"Although successful cornea transplant surgeries are
considered routine even with older surgical techniques, our
patients experience a more rapid recovery of their vision after
the new DSEK procedure," said Alan Carlson, M.D.,
ophthalmologist and chief of the cornea service at Duke. "With
the older, full thickness transplant techniques, the eye is
never structurally as strong as it was before the surgery. This
newer way of performing cornea transplants is a quantum leap.
To me, this is as big a deal as the development of arthroscopic
surgery was to knee repair or laparoscopic surgery for the
abdomen."

Approximately 35,000 cornea transplants are performed each
year in the U.S. Use of the DSEK technique is limited to
patients with damage to the endothelial area of the cornea,
which accounts for about two-thirds of these cases, Carlson
said.

The cornea is comprised of several layers, including
Descemet's membrane and the endothelium. Descemet's membrane is
a thin layer that supports endothelial cells on the back of the
cornea. The endothelium, comprised of endothelial cells, is the
delicate back portion of the cornea that manages fluid content
within the corneal structure.

In a DSEK procedure, the surgeon removes the inner-most
layer of the endothelium along with Descemet's membrane. That
section is then replaced with a delicate healthy layer of
donated human cornea tissue. Using specialized tools, the new
tissue is positioned into the cornea. The new tissue heals
without sutures.

"There isn't anything more exciting to me as a surgeon than
DSEK right now," Carlson said. "The shorter recovery time and
the retained integrity of the eye mean that my patients will be
able to live a fuller life and resume regular activities with
much fewer worries than my patients from even a year ago."

The most common reasons people need cornea transplants are
Fuchs' dystrophy, traumatic injury to the eye area, previous
eye surgery and diseases that affect the endothelium. Diseases
and injuries that destroy the endothelium can lead to
blindness, at which time a cornea transplant is the only
treatment that can restore vision.

According to Carlson, a patient can regain useful vision
within two weeks and driving vision within two to three months
following the DSEK procedure, as opposed to six and 12 months,
respectively, with the older method.

The biggest risks following a full cornea transplant include
tissue rejection, glaucoma and slow healing at the incision
site. Another major problem can occur when a patient falls or
otherwise accidentally injures the eye with the transplanted
cornea. Since a full cornea transplant weakens the eye, falling
after surgery or being accidentally poked in the eye can
seriously damage the transplant and surrounding tissue. With
structural integrity of the eye maintained with the DSEK
technique, such injuries are less of a problem, hence reduced
fear on the part of a recovering patient, Carlson said.

The DSEK technique is currently available in limited areas
throughout the U.S. and is growing in popularity.

The procedure has even greater potential in Third-World
countries where cornea diseases are prevalent. There, cornea
transplantation is rarely an option due to the specialized care
that has been needed following full-thickness cornea
transplants. Infections, donor tissue rejection and problems
with hygiene are problems inherent to transplantation in all
parts of the world, but in the Third World such transplants are
largely impractical due to a shortage of eye specialists and
other physicians, according to Carlson.

"It will be incredible to take this technique to other
countries where so many people suffer from corneal blindness,"
Carlson said. "In many places in the world, if a person cannot
see, they won't be able to survive. I believe this advance will
really help change the human condition in places where this
type of hope is needed."