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.

Symptoms
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 RP, 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.

As the disease progresses and more rod cells degenerate, patients lose their peripheral vision. Patients with retinitis pigmentosa often experience a ring of vision loss in their mid-periphery with small islands of vision in their very far periphery. Others report the sensation of tunnel vision, as though they see the world through a straw. Many patients with retinitis pigmentosa retain a small degree of central vision throughout their life.

Other forms of retinitis pigmentosa, sometimes called cone-rod dystrophy, first affect central vision. Patients first experience a loss of central vision that cannot be corrected with glasses or contact lenses. With the loss of cone cells also comes disturbances in color perception. As the disease progresses, rod cells degenerate causing night blindness and peripheral vision.

Symptoms of retinitis pigmentosa are most often recognized in children, adolescents and young adults, with progression of the disease continuing throughout the individual’s life. The pattern and degree of visual loss are variable.

Related diseases
Other inherited diseases share some of the clinical symptoms of retinitis pigmentosa. Usher syndrome is the most common of these, which causes both hearing and vision loss.Some of these conditions are complicated by other symptoms besides loss of vision. Other rare syndromes that researchers are studying with funding from The Foundation Fighting Blindness include Bardet-Biedl (Laurence-Moon) syndrome, Best disease, choroideremia, gyrate-atrophy, Leber congenital amaurosis, and Stargardt disease.

Retinitis pigmentosa and related diseases are rare and difficult to accurately diagnose. Only a specialist can properly distinguish between the subtle clinical features of these diseases. Therefore, it is important that patients who are symptomatic see an ophthalmologist who specializes in retinal degenerative diseases.

Treatments
As yet, there is no known cure for retinitis pigmentosa. However, intensive research is currently under way to discover the cause, prevention, and treatment of retinitis pigmentosa. At this time, retinitis pigmentosa researchers have identified a first step in managing retinitis pigmentosa. While not a cure, certain doses of vitamin A have been found to slightly slow the progression of retinitis pigmentosa in some individuals. An information packet on this research breakthrough is available from The Foundation. Researchers have found some of the genes that cause retinitis pigmentosa. It is now possible, in some families with X-linked retinitis pigmentosa or autosomal dominant retinitis pigmentosa, to perform a test on genetic material from blood and other cells to determine if members of an affected family have one of several retinitis pigmentosa genes.