Causes, incidence, and risk factors
Retinitis pigmentosa commonly runs in families. The disorder can be caused by defects in a number of different genes which
have recently been identified.
The cells controlling night vision, called rods, are most likely to be affected. However, in some cases, retinal cone cells
are most damaged. The hallmark of the disease is the presence of dark pigmented spots in the retina.
As the disease progresses, peripheral vision is greadually lost. The condition may eventually lead to blindness, but usually
not complete blindness. Signs and symptoms often first appear in childhood, but severe visual problems do not usually develop
until early adulthood.
The main risk factor is a family history of retinitis pigmentosa. It is an uncommon condition affecting about 1 in 4,000 people
in the U.S.
The disorder will continue to progress, though at a very slow pace. Complete blindness is uncommon.