Retinitis pigmentosa

Primary symptoms include impaired night vision, problems with dark adaptation, decreased peripheral vision, and eventually decreased visual acuity.

Electroretinograms help confirm the diagnosis by demonstrating attenuated rod and cone signals.

Onset and pattern of degeneration vary but most cases demonstrate atrophy of the retina and retinal pigment epithelium, bone spicule pigmentation, waxy pallor of the optic nerve, and retinal vascular attenuation.

There is no cure. Vitamin A supplementation and docosahexaenoic acid (fish oils) are given in some centers with the aim of slowing retinal degeneration. Gene replacement therapy has demonstrated improved functional vision in patients with RPE65-mediated inherited retinal dystrophy.

Retinitis pigmentosa (RP) is a term that encompasses a broad category of hereditary conditions of retinal degeneration that share a common pathophysiology.[1]Weleber RG, Gregory-Evans K. Retinitis pigmentosa and allied disorders. In: Ryan SJ, ed. Retina, 4th ed. Philadelphia, PA: Elsevier Mosby; 2006:395-498.[2]Heckenlively JR. Retinitis pigmentosa. Philadelphia, PA: Lippincott; 1988.[3]Hartong DT, Berson EL, Dryja TP. Retinitis pigmentosa. Lancet. 2006;368:1795-1809. http://www.ncbi.nlm.nih.gov/pubmed/17113430?tool=bestpractice.com Symmetrical retinal degeneration is caused by a genetic mutation in 1 of over 100 different genes, leading to loss of rod and cone photoreceptors in the retina. Inheritance can be autosomal dominant, autosomal recessive, X-linked, or, rarely, mitochondrial or digenic. It most commonly presents with night blindness and progressive loss of peripheral vision.[4]Pruett RC. Retinitis pigmentosa: clinical observations and correlations. Trans Am Ophthalmol Soc. 1983;81:693-735. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1312466/pdf/taos00018-0717.pdf http://www.ncbi.nlm.nih.gov/pubmed/6676982?tool=bestpractice.com The timing, patterns, and course can be heterogeneous. Cone-rod and cone dystrophies are sometimes classified separately from RP, but increased genetic knowledge is revealing that these disorders are part of the RP spectrum.