Every year, corneal transplants improve or even restore eyesight for 40,000 people in the United States. But for thousands of others, the operations don't work. In many of these patients, damage to the cornea—the clear windshield covering the eye—is just too severe for the traditional approach.
Scientists now have grown corneal tissue in laboratory dishes and successfully transplanted it onto the injured eyes of such patients, some of whom couldn't see beyond a few feet before the operations. This procedure, which uses stem cells in the cornea to replenish worn-out cells, improved sight in most patients.