Retinitis Pigmentosa 72

Background and History: 

Retinitis pigmentosa, or RP, is a generic name given to a large group of progressive hereditary diseases whose main feature, at least early, is decreased night vision.  The clinical features include loss of vision, cataracts, and the constriction of the field of vision.  Many of the clinical features are present in other metabolic, infectious or traumatic eye conditions.

Clinical Correlations: 

In the condition addressed here the onset of vision problems initially at night can occur in the fourth and fifth decades.  It is likely that some symptoms of decreased daytime vision occur earlier in certain individuals.  The loss of side vision (constriction of the field of vision) may be noted about the same time.  Some individuals have 20/20 vision when tested early in the disease while others experience only mild loss to perhaps 20/40, at least early.  Vision loss occurs slowly and there is usually some variation in the rate of loss among patients.  Cataracts often develop.

Examination by an ophthalmologist usually reveals some pigment changes in the retina even early.  The retinal blood vessels are narrowed and in later stages the optic nerve becomes pale.  Some but not all patients have cataracts in later stages.  A specialized test known as an ERG (electroretinogram) even in early stages of disease reveals loss of function in the light-sensing cells of the retina (cones and rods, especially the latter).  A visual field test can document the constriction of the field of view.

There are no abnormalities in other parts of the body in this condition.


This type of retinitis pigmentosa requires the mutation of both members of a gene pair characteristic of autosomal recessive disorders.  Parents who carry only one of these mutations are clinically normal but the children born to parents who each carry one have a 25% risk of inheriting this form of retinitis pigmentosa.

Diagnosis and Prognosis: 

Infants appear to be normal at birth.  Those with two copies of the mutation later note loss of vision and examination by an ophthalmologist at that time usually reveals changes in the retina on a full examination.  There is no known treatment.  Some individuals benefit from specially tinted eyeglasses.  Patients should be monitored throughout their lives since some improvement in vision can be obtained by surgical removal of visually significant lens opacities (cataracts).

Additional Information