|
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 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."
Learn more about Duke Physicians who provide this cornea transplantation.
 | 
