RP is a group of hereditary disorders whose common feature is a gradual deterioration of the retina's light sensitive cells.

The name Retinitis Pigmentosa was applied by a Doctor Donders in 1857.

The symptoms of this group of disorders usually become apparent between the ages of 10 and 30.

Sufferers usually experience months or years of not being able to see properly in the dark, and stumbling and falling over objects which the sufferer has not seen, before a positive diagnosis is made.

There is no cure for RP and the British Retinitis Pigmentosa Society says the first and hardest step to living with such a disability is accepting it.