 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 they
develop.
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