Summary

• Symmetrical retinal degeneration 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.
• 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 (retinol) supplementation and docosahexaenoic acid (fish oils) are given in some centres with the aim of slowing retinal degeneration.