Those with healthy vision can read the words on this page due to cells called rods and cones that nestle in the retina, which lines the back of the eyeball. Both cell types detect light rays from an object and convert them into electrical signals which are relayed to the brain. Rods are sensitive to dim light, while cones work in bright light. With RP, first the rods deteriorate, which causes the field of vision to narrow and makes it difficult to see at night. Later the cones breakdown.
Sight becomes blurry and eventually nonexistent.
Researchers, however, are building on earlier studies to find ways to counter the disease. For example, some are examining the advantages of using special transport systems to deliver genetic material into the eye. The researchers may ultimately test the technique in humans. Another line of research involves supplements of small proteins that naturally prevent injury and block the death of eye cells. These survival factors could be administered directly via injection, through an implanted device that releases the proteins or with gene therapy techniques.