Retinitis pigmentosa (RP) consists of a large group of disorders 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 are responsible for these hereditary disorders and there is considerable variation in onset and progression of symptoms. Retinitis pigmentosa 76 signs and symptoms are limited to the eye.
Symptoms of night blindness usually have their onset in the second decade of life in this condition. Visual acuity early is only mildly affected (children are usually able to read) but deteriorates slowly with age to legal blindness (20/200) or hand motions. The field of vision becomes restricted as peripheral areas lose their responsiveness to light resulting in 'tunnel vision'. Inside the eye the retinal pigment is characteristically clumped in a recognizable pattern known as 'bone spicule' pigmentation. The retinal vessels are abnormally narrow which is described in the medical literature as 'attentuation'. The optic nerve which connects the eye to the brain shows damage as well.
A gene change (mutation) in both members of a specific pair is responsible for this condition. The parents who only carry the change in a single member of the pair are clinically normal but if both carry this change, each of their children are born with a 25% risk of developing this form of retinitis pigmentosa.
Only the eyes demonstrate changes as the result of the mutation and patients are otherwise healthy. An eye physician can diagnose this condition based on the symptoms and the characteristic changes in the retina and optic nerve. An electroretinogram (EKG) test may be used to confirm the diagnosis. There is no known treatment and no impact on general health or longevity.
Low vision aids could be beneficial, especially for school age children.