Retinitis Pigmentosa

Retinitis Pigmentosa (RP) is the name given to a group of inherited eye diseases that affect the retina. Retinitis pigmentosa causes the degeneration of photoreceptor cells in the retina. Photoreceptor cells capture and process light helping us to see. As these cells degenerate and die, patients experience progressive vision loss.

There are types of photoreceptor cells: rod cells and cone cells. Rod cells are concentrated along the outer perimeter of the retina. Rod cells help us to see images that come into our peripheral or side vision. They also help us to see in dark and dimly lit environments. Cone cells are concentrated in the macula, the center of the retina, and allow us to see fine visual detail in the center of our vision. Cone cells also allow us to perceive color. Together, rods and cones are the cells responsible for converting light into electrical impulses that are transmitted to the brain where “seeing” actually occurs.

The most common feature of all forms of Retinitis Pigmentosa is a gradual degeneration of the rods and cones. Most forms of RP first cause the degeneration of rod cells. These forms of Retinitis pigmentosa, sometimes called rod-cone dystrophy, usually begin with night blindness. Night blindness is somewhat like the experience normally sighted individuals encounter when entering a dark movie theatre on a bright, sunny day. However, patients with Retinitis pigmentosa cannot adjust well to dark and dimly lit environments.