Retinitis Pigmentosa is the name given to a
group of diseases which affect the retina of the eye.
The retina, located in the back of the eye, is the part of the eye that acts
like the film in a camera. It is a delicate layer of cells which picks up the
picture and transmits it to the brain - where "seeing" actually occurs. In RP,
the retina begins to degenerate, which causes vision to diminish.
One of the earliest symptoms of RP is difficulty seeing at night or in dimly lit
places (night blindness). Later there is a reduction in side (peripheral)
vision. The symptoms of RP generally increase over the years.
It is known that certain cells in the retina, known as rods and cones, die in
RP. The cause of cell death however, is not known at present, but research
provides us with the opportunity to seek solutions.
The symptoms of RP may occur at any age but most commonly they become apparent in young people in their late teens or early twenties.
Normal Vision Tunnel Vision
RP first presents difficulties with night vision
or under conditions of dull lighting and may cause progressive loss of
peripheral or side vision.
There is a very wide spectrum of severity and at the mild end some people never
lose their sharp vision while at the severe end there may be a loss of useful
vision in early adult life. Although the condition is slowly progressive, the
rate at which deterioration occurs is extremely variable and it is important to
undergo clinical testing on two or three occasions to determine the likely long
term outcome.
Most people with RP can remember difficulty seeing at dusk or at night during
childhood and as the symptoms become more noticeable, RP is diagnosed between
the age of 10 and 30 years. During this time he or she becomes aware of
progressive loss on the outer edges of the field of vision.
As the condition progresses, the side vision reduces to the point where only a
small central area or tunnel vision remains. In the late phases central reading
vision may also be lost.