New Artificial Cornea Shows Promise
Researchers Developing Polymer-Gel Cornea That Would Replace Need for Human Donors
May 16, 2008 -- Researchers from Stanford University have developed an
artificial cornea, which they say could make cornea transplants involving donors a
thing of the past and help millions of blind people see again.
The polymer-based cornea has not been implanted in humans, but it is showing
promise in animal studies, Stanford senior scientist Jaan Noolandi, PhD, tells
Corneal disease is a leading cause of blindness. Examples of corneal disease
include infection such as ocular herpes and corneal dystrophy such as keratoconus. It is estimated
that 10 million people worldwide have lost their sight to corneal disease or
Transplants from cadaver donors are not an option in many parts of the
world, due to shortages of donors or religious barriers to human tissue
"There is really a global market for an artificial cornea, and we
believe that our material will prove more biocompatible than those that have
been tried in the past," Noolandi says.
Doing Away With Donors
Developed by chemical engineer Curtis W. Frank, PhD, the cornea is made of
two interwoven polymer gels, similar to the materials used in soft contact
One layer is exceptionally strong while the other is able to absorb a
tremendous amount of water.
The result is a transparent, highly permeable substance with a water content
similar to that of the natural cornea, Noolandi says.
"Without a high water content the nutrients that feed the cells within
the eye can't penetrate and the cells eventually die," he adds.
If the artificial cornea proves successful in human studies, it could one
day replace donor transplants.
But that is a very big if, says corneal disease specialist Ivan Schwab,
"There have been dozens of attempts to come up with some version of an
artificial cornea over many decades," he tells WebMD. "Most have looked
promising in the lab but have proven disappointing otherwise."
He says that is the case with one of the only artificial corneas now
approved for use in the U.S., which was developed by researchers in
The failure rate among patients who get the AlphaCor cornea is about 20% a
"Until the [Stanford] researchers publish human, or even animal studies,
we won't really know if their approach is promising," he says. "They
may have something terrific, but I am skeptical because of the many previous
Human Studies Needed
Harvard Medical School professor of ophthalmology Claes H. Dohlman, MD, PhD,
has been conducting cornea research for more than 50 years, and he is
considered a founder of modern corneal science.
The artificial cornea he developed has been used in the U.S. since 1992 in
patients who are not candidates for donor transplants.
His artificial cornea cannot be used when corneal damage is caused by
autoimmune disease, but Dohlman says it works very well in other patients.
"The search [for a safe and effective artificial cornea] goes as far
back as the surgeons of the French Revolution, with mostly disastrous
results," he tells WebMD. "It has only been within the last few decades
that the elements have come together to make this a reality."
Dohlman agrees that it remains to be seen if the artificial cornea developed
by the Stanford researchers will advance the search for a donor transplant
"This is a very good research team, but they still have a long way to
go," he says.