Retinitis pigmentosa, or RP, is when there is retinal damage caused by genetic defects. The cells controlling that night vision, or rods, are damaged and so are the retinal cone cells. There can be dark deposits in the retina. This condition can also be known as rod-cone dystrophy, or progressive pigmentary retinopathy. It was first mentioned in 1855 by the Dutch ophthalmologist Franziscus C. Donders. The condition affects night vision among other visual disorders and can lead in some cases to total blindness. Some of the most severe signs do not happen until early adulthood. Symptoms of RP...