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This page provides a brief overview of retinitis pigmentosa. For a longer discussion about living with this condition, please see the Foundation Fighting BlindnessGuide to Retinitis Pigmentosa and Related Conditions. Last updated in 2006, this guide was designed to give you, your family and friends a better understanding of your condition and to aid in discussions with your ophthalmologist and/or specialist.

Retinitis pigmentosa (RP) is a genetic condition that slowly damages the retina. The condition progresses throughout a persons life, affecting about 1:3500Canadians.

RP is usually diagnosed in childhood or adolescence, although some people have no recognized symptoms until their adult years. The most common early symptom is difficulty seeing at night and adapting to dim light conditions. This is called nyctalopia (night blindness). People also begin to lose peripheral vision quite early in the disease.

RP occurs because the light-sensing retinal cells, called photoreceptors, are slowing damaged due to an inherited genetic mutation. Many different mutations can cause RP.

There are two types of photoreceptors: rod cells and cone cells. Rod photoreceptors are responsible for peripheral vision and night vision; cone photoreceptors are responsible for central vision and for seeing fine detail and colours. Night blindness occurs early in RP because the mutations that cause RP damage the rod cells first.

Over time, as more rod photoreceptors are lost, cell death also occurs amongst the cone cells. This is not well understood, but cone cell loss seems to be triggered by the death of rod cells. When cones die, central vision and visual acuity are lost.

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The Foundation Fighting Blindness - Retinitis Pigmentosa