Retinitis Pigmentosa – VisionAware

By Frank J. Weinstock, MD

Retinitis pigmentosa (RP) is part of a large group of hereditary retinal conditions or dystrophies. There is considerable overlap among the various types. It usually refers to a group of hereditary conditions involving one or several layers of the retina, causing progressive degeneration. Primarily the rods (light-sensitive, specialized retinal receptor cell that works at low light levels and provides night visionnormal retina contains 150 million rods) of the retina are involved, but there may also be some involvement of the cones. With this progressive degeneration of the retina, usually you retain central vision until late in the disease as the periphery slowly constricts.

Retinitis pigmentosa is primarily a bilateral inherited condition which involves both eyes and is generally diagnosed later in life. If it starts in one eye, the other eye usually develops the same condition in a number of years. It is essential that you undergo a thorough genetic pedigree with the aid of a genetic counselor.

It occurs in 1 in 4,000 people in the United States. A related condition, Usher syndrome may show up early in life. This is accompanied by hearing loss which might be significant. Here is a first-hand account of what it is like to live with Usher Syndrome.

Since retinitis pigmentosa is a rod dystrophy, starting in the periphery of the visual field, you will start to notice an increasing difficulty in night vision with progressive constriction of the visual field to tunnel vision (a visual field: the total area an individual can see without moving the eyes from side to side) of 20 degrees or less (often known as "tunnel vision") in the better-seeing eye, and total blindness eventually.

Article originally published: http://www.medicinenet.com/retinitis_pigmentosa/article.htm Adapted for VisionAware: August 2013

Read the original post:
Retinitis Pigmentosa - VisionAware