Retinitis pigmentosa (RP) is a group of genetic diseases that causes slow, progressive loss of vision. This loss of vision results from the gradual degeneration of cells in the retina, the light-sensitive tissue that lines the back of the eye.
RP is considered to be a rare disorder. General estimates suggest that this condition affects approximately 1 in 4000 people.
RP is typically an inherited disorder due to mutations that may be present in any one of over 50 genes. These genes provide instructions for making essential proteins for retinal cells, or photoreceptors. Some of these mutations produce proteins that are toxic to the photoreceptors, some produce proteins that do not function properly, and other mutations are so extensive that the gene cannot make any protein at all. All of these changes damage the photoreceptors and thus limit their function.
The main symptoms of RP are night blindness (or difficulty adjusting to the dark) and loss of side vision. Loss of peripheral vision makes mobility, and daily activities such as driving, reading and recognizing faces and objects very difficult. At this point, central vision is most of what remains.
The symptoms RP are often first noticed in childhood or young adulthood. An individual affected by RP may have difficulty moving around in the dark, and may take an abnormally long time to adjust to changes in lighting conditions.
As the loss of peripheral vision becomes noticeable, patients often bump into things and appear clumsy. Additionally, people with RP often experience discomfort in bright lights.
Because there are so many different mutations that can result in RP, its progression can vary dramatically between those affected. Unfortunately, most people with RP eventually lose most of their sight.
RP can be diagnosed in part by a thorough retinal examination. An eye care professional will want to dilate your pupils to allow for a clearer view of the retina. In RP, dark pigmented deposits in the peripheral retina are often noted. Other tests to aid in the diagnosis include:
Unfortunately, there is no cure or treatment for RP. Developments, most notably in the area of genetic research, are currently being made.