The treatment worked completely in 82 of 107 eyes and partially in 14 others, with benefits lasting up to a decade so far. One man whose eyes were severely damaged more than 60 years ago now has near-normal vision.
"This is a roaring success," said ophthalmologist Ivan Schwab of the University of California at Davis, who had no role in the study.
Stem cell transplants offer hope to people who suffer chemical burns on their corneas from heavy-duty cleansers or other substances at work or at home. Such accidents affect thousands worldwide every year.
The stem cell approach would not help people with damage to the optic nerve or macular degeneration, which involves the retina. Nor would it work in people who are completely blind in both eyes, because doctors need at least some healthy tissue that they can transplant.
In the study, published online by the New England Journal of Medicine, researchers took a small number of stem cells from a patient's healthy eye, multiplied them in a lab and placed them into the burned eye, where they were able to grow new corneal tissue to replace what had been damaged. Since the stem cells are from their own bodies, the patients do not need to take anti-rejection drugs.
The study involved 106 patients treated between 1998 and 2007. Most had extensive damage in one eye, and some had such limited vision that they could only sense light or perceive hand motions. Many had been blind for years and had had unsuccessful operations to restore their vision.
Adult stem cells have been used for decades to cure blood cancers such as leukemia and diseases including sickle cell anemia. But fixing damaged eyes is a relatively new use.
Researchers have been studying cell therapy for a host of other diseases, including diabetes and heart failure, with limited success.
-- Associated Press