Retinitis pigmentosa (RP) consists of a large group of hereditary disorders with reduced vision resulting from a progressive loss of the rods and cones in the retina. These are the cells that respond to light and send signals to the brain that enable us to see. Hundreds of mutant genes have been identified in these disorders and there is considerable variation in onset and progression of symptoms. The disease usually is present as an isolated eye disease but syndromal forms also occur in which there is a similar disease of the retina in association with problems elsewhere in the body.
The descriptive title is derived from impressions of years ago that there was an inflammatory process in the retina that resulted in changes in pigmentation.
Children as young as 5 years of age may complain of vision problems in dim light. Their vision in daylight is also decreased and progressively worsens. Examination of the eye in children and young adults reveals pigmentary and vascular changes characteristic of retinitis pigmentosa that becomes more marked as they grow older. The optic nerve that connects the eye to the brain may be pale. Special tests such as the electroretinogram (ERG) documents dysfunction of the rods and cones.
This is an autosomal recessive condition in which both members of a gene have been changed (mutated). Individuals such as parents with only one changed gene have normal eyes and vision. However, each offspring of two such parents with one mutation has a 25% risk that they will inherit this condition.
It is unknown when the first signs of retinal disease can be detected but children as young as 5 years of age may complain of night vision problems. Evidence of retinitis pigmentosa can be seen in the retina in young adults and become more marked with age. An ERG test should be done in all members of the family when the diagnosis is suspected.
No effective treatment has been reported. However, low vision devices can be helpful for educational purposes especially in young people. Sometimes tinted lenses are helpful to improve contrast.