Rods and Cones. Millions of them are in the back of every healthy human eye. They are biological solar cells in the retina that convert light to electrical impulses. Many people are blind -- or going blind -- because of malfunctioning rods and cones. Using space technology, scientists have developed ceramic photocells that could repair malfunctioning human eyes.
"If we could only replace those damaged rods and cones with artificial ones," says Dr. Alex Ignatiev, a professor at the University of Houston, "then a person who is retinally-blind might be able to regain some of their sight"