Age-related macular degeneration (AMD) is a progressive disease of the retina that develops when the light-sensing cells in the central area of vision (the macula) stop working and eventually die. Thought to be caused by a combination of genetic and environmental factors, the disease is the leading cause of blindness in people over 50. In 1995, Dan Roberts retired from teaching to help others who also suffered from macular degeneration. Roberts has...