Retinitis pigmentosa (RP) describes a group of related
diseases that tend to run in families and cause a slow but progressive loss of
vision. RP affects the rods and cones of the retina, the light-sensitive nerve
layer at the back of the eye, and results in a decline in vision in both eyes.
RP usually affects both eyes equally with severity ranging from no visual
problems in some families to blindness at birth in others. RP gets its name
from the fact that one of the symptoms is a clumping of the retinal pigment
that can be seen during an eye exam.
The earliest symptom of retinitis pigmentosa, usually
noticed in childhood, is night blindness or difficulty with night vision.
People with normal vision adjust to the dark quickly, but people with night
blindness adjust very slowly or not at all. A loss of side vision, or tunnel
vision, is also common as RP progresses. Unfortunately, the combination of
night blindness and the loss of peripheral vision can be severe and lead to
legal blindness in many people.
While there is a pattern of inheritance for RP, 40% of RP
patients have no known previous family history. Learning more about RP in your
family can help you and your ophthalmologist predict how RP will affect you.
Usher's syndrome, in which a person is both deaf and
blind, can be associated with RP. The incidence of Usher's syndrome is
difficult to determine but surveys of patients suggest up to 10% of RP patients
are deaf. The incidence of Usher's syndrome is three cases per 100,000. It is
the most frequent cause of combined deaf-blindness in adults.
Considerable research is being done to find the hereditary
cause of RP. As hereditary defects are discovered it may be possible to develop
treatments to prevent progression of the disease. While developments are on the
horizon, particularly in the area of genetic research, there is currently no
cure for retinitis pigmentosa.
Nutritional supplements may have an effect on RP. It has
been reported that Vitamin A can slow the progression of RP. Large doses of
Vitamin A are harmful to the body and supplements of Vitamin E alone may make
RP worse. Vitamin E is not harmful if taken with Vitamin A or in the presence
of a normal diet. Your ophthalmologist can advise you about the risks and
benefits of Vitamin A and how much you can safely take.
Despite visual impairment, people with RP can maintain
active and rewarding lives through the wide variety of rehabilitative services
that are available today. Until there is a cure, periodic examinations by your
ophthalmologist will keep you informed of legitimate scientific discoveries as