Gene therapy developed to treat blindness

Doctors may one day treat some forms of blindness by altering the genetic program of the light-sensing cells of the eye, U.S. researchers say. Senior author Dr. Joseph Corbo, an assistant professor of pathology and immunology at Washington University School of Medicine in St. Louis, said working with mice with retinitis pigmentosa -- a disease that causes gradual blindness -- the researchers reprogrammed the cells in the eye that enable night vision. The change made the cells more similar to other cells that provide sight during daylight hours and prevented degeneration of the retina, the light-sensing structure in the back of the eye, Corbo said. The scientists said they were conducting additional tests to confirm that the mice could still see. "We think it may be significantly easier to preserve vision by modifying existing cells in the eye than it would be to introduce new stem cells," Corbo said in a statement. "A diseased retina is not a hospitable environment for transplanting stem cells." The study was published in the early online edition of Proceedings of the National Academy of Sciences.