Canadian scientists envision synthetic corneas
Published Wednesday, August 25, 2010 6:51PM EDT
Canadian researchers may have made a breakthrough in the treatment of blindness caused by damaged corneas.
They've developed a biosynthetic cornea that can actually help the eye repair its own damaged eye tissue and restore vision. And with further research, they say their approach could help restore sight to millions of people around the world who have lost their sight from diseases that lead to clouding of the cornea.
The research, published today in the journal Science Translational Medicine is a small one, involving just 10 people. But scientists say they were surprised that the treatment worked in the majority of patients who had scarred corneas, helping to restore the sight of nine of the 10 patients.
The cornea is the thin, transparent layer of collagen and cells that acts as a window on the eyeball. In most cases of corneal damage, only a transplant can restore sight.
But in this research, Dr. May Griffith of the Ottawa Hospital Research Institute, the University of Ottawa and Linköping University in Sweden created corneas using biosynthetic collagen produced in the lab that was moulded into the shape of a cornea, much like a contact lens.
After first testing the corneas on pigs (who have eyes similar to humans), they recruited 10 Swedish patients with advanced keratoconus, or central corneal scarring. Each patient underwent surgery in 2007 to remove damaged corneal tissue. That was then replaced with corneas made from synthetic human collagen, which were sewn onto the eyes.
For two years, researchers watched what happened. Over time, the implants acted as scaffolding to help the eye restore normal corneal cell and nerve growth.
"You put the material in the eye and it becomes almost an integral part. It allows the natural cells of the person treated to go into the material and become part of it," co-author Rejean Munger of the Ottawa Hospital Research Institute told CTV News.
The corneas even became sensitive to touch and started making tears to keep the eyes oxygenated.
Griffith says while the study was intended only to test the safety of the new corneas, her team found that nine of the 10 patients saw their vision improve, though some needed to wear contact lenses. The 10th patient is improving though much more slowly.
"We were actually very surprised and happy that we saw improvement in the vision," Griffith said.
"After surgery, patients didn't have perfect vision, but they could see better," she says. "One patient had almost perfect vision; others had slightly less than perfect vision."
The research was published Wednesday in the journal Science Translational Medicine.
Dr. Keith Gordon of the CNIB notes that there are millions of people in Canada and around the world who need new corneas, but there is a dire shortage of donor corneas. A synthetic cornea from a lab would be an important new way of treating patients.
"If these transplants are as effective as they appear to be, we have got a winner. And it will be exciting and useful for people with vision loss due to corneal disease," he says.
Researchers think it will take another five years to further improve the implants, and to test them in other eye conditions.
With a report from CTV's medical specialist Avis Favaro and producer Elizabeth St. Philip