Retinitis Pigmentosa (RP) is the most common retinal dystrophy occurring in about 1 in 1000 people.  Several genetic mutations have been discovered that cause this retinal dystrophy.  RP is sometimes inherited and sometimes occurs in a person with no family history of vision problems.  There is a range of expression of the disease.  Some patients, like the one pictured on the right present after age 50 with mild central vision loss and peripheral vision loss.  Some present at a young age with severe central vision loss.

 

At this time, there is not treatment for retinitis pigmentosa.  Although one researcher found that high dose vitamin A can slow progression of electroretinographic decline in patients with retinitis pigmentosa, since there was no symptomatic benefit in patients, most retina specialists do not recommend this therapy.  An exciting study of people with Leber's Congenital Amaursis, which is a severe retinal dystrophy similar to RP that is present at birth, showed a benefit to a small group of patients treated with gene therapy.

At least 35 different genes are known to cause retinitis pigmentosa.

RP can be inherited in an autosomal dominant, autosomal recessive, or x-linked manner. X-linked RP can be either recessive, affecting primarily only males, or dominant, affecting both males and females, although females are usually more mildly affected.

Genetic counseling depends on an accurate diagnosis, determination of the mode of inheritance in each family, and results of molecular genetic testing.

RP combined with progressive deafness is called Usher syndrome.

Visual acuity and visual field testing is helpful in assessing patients with retinitis pigmentosa. In general, a patient who presents with a fundus that looks like the one on the right has RP.  If the diagnosis is in question, such as a patient with an atypical appearing fundus, or a patient who does not have symmetrical disease, fluorescein angiography and electroretinography are helpful.

 

Unfortunately, not many centers currently offer electroretinographic testing. At this moment (July 2008), no one in Tampa Bay offers the test. It can be done in Miami at the Bascom Palmer Eye Institute. 

Since there is a wide variability in patients with retinitis pigmentos, the prognosis is different for each case.  In patients with a family history of RP, the disease tends to behave similarly in affected family members.  Also, the younger the onset of disease, the worse patients tend to do.

 

Although there is not therapy for retinitis pigmentosa, there are reasonable precautions patients should consider.  Since smoking is damaging in patients with many retinal diseases, it should be avoided in everyone, especially retinitis pigmentosa.

 

Viagra has a small affect on an enzyme that is active in the phototransduction cascade.  Many retina specialists recommend that patients with retinal dystrophies, like RP, avoid Viagra.

 

Low cholestrol, normal blood pressure, and a healthy diet are good for everyone and may be helpful in patients with RP.  Most patients with RP have difficulty with light and dark adaptation.  Sunlight may accelerate damage to eyes with RP and protective sunglasses, with UV and Blue Blocker should be considered by patients with RP.