Retinitis pigmentosa, or RP, is a group of inherited eye diseases that cause degeneration of the retina and progressive vision loss. It is variable in severity but can cause total loss of vision in some individuals.
The retina, a light-sensing layer at the back of the eye, sends impulses to the brain, which interprets what we see. The nerve cells in the retina, called rods and cones, react to light with a photochemical reaction. But in some people, there is a problem with these nerve cells or with the retinal pigment epithelium, which nourishes the retinal visual cells.
In retinitis pigmentosa, the nerve cells degenerate and die, causing patients to experience gradual vision loss. In most cases, the rods stop working. Vision loss is manifested by loss of peripheral and night vision. In some cases, the cones degenerate, affecting vision concentrated in the retina’s center. The hallmark of the disease is dark pigmented spicules in the retina.
Retinitis pigmentosa has no cure, either from surgery or treatments by medicine.
Who is most at risk?
Retinitis pigmentosa is a rare disorder, affecting about 1 in 4,000 people in the United States, or about 100,000 total. It is hereditary, caused by defects in a number of different genes. Some forms of retinitis pigmentosa are associated with deafness, kidney disease and other malfunctions, central nervous system and metabolic disorders, and chromosomal abnormalities. Signs and symptoms often first appear in childhood, but severe visual problems often develop in early adulthood. In fact, the majority of people with retinitis pigmentosa are legally blind by age 40.
How is retinitis pigmentosa inherited?
Autosomal dominant inheritance affects both male and female. The probability of retinitis pigmentosa being passed on from an affected parent is 50 percent. Autosomal recessive inheritance can occur with no known family history of retinitis pigmentosa. If a parent is a carrier, there is a 25 percent chance of them giving birth to a child with retinitis pigmentosa. X-linked inheritance only affects males, but females are the carriers. If a man with retinitis pigmentosa has a daughter, she will automatically be a carrier. She then has a 50 percent chance of having an affected son, and that son has a 50 percent chance of having a daughter who is a carrier.
What are the symptoms of retinitis pigmentosa?
- Progressive retinal degeneration
- Night blindness
- Loss of peripheral vision
- Loss of central vision (in advanced cases)
- Progressive overall vision loss