Promising treatments for those blinded by an often-hereditary, retina-damaging disease are expanding throughout Europe and making their way across the pond, offering a ray of hope for the hundreds of thousands of people in the U.S. left in the dark by retinitis pigmentosa. The disease—which affects about one in 4,000 people in the U.S. and about 1.5 million people worldwide—kills the retina’s photoreceptors, the rod and cone cells that convert light into electrical signals, which are transmitted via the optic nerve to the brain’s visual cortex for processing.
http://www.huffingtonpost.com/2011/12/12/retinitis-pigmentosa-treatments-implants-_n_1143363.html