Julia Levy of Vancouver still remembers the day in the mid-1980s when her heart broke. She was sitting across the dining-room table from Dorothy Coppens, her vibrant 85-year-old mother, who had just been found to be suffering from macular degeneration, an incurable deterioration of the central portion of the retina that is the leading cause of blindness in people 60 and older. "Your face is just a brown smear," Coppens told her daughter. "I guess I'll never see your face again."
Like a lot of folks, Levy had never heard of macular degeneration. Unlike most, she was in a position to...