1. Light micrographs of a normal human retina (left), a retina with retinitis pigmentosa (center), and a retina with end-stage retinitis pigmentosa (right). Light rays enter from the top of the figure. A photon must pass through the nerve fiber layer, ganglion cell layer, inner plexiform layer, bipolar cell layer, outer plexiform layer, and photoreceptor nuclear layer before reaching a photoreceptor outer segment, where it can interact with rod or cone opsin to initiate vision. The center panel shows histologic changes observed in eyes with early to moderately advanced retinitis pigmentosa. The photoreceptor outer segments are absent, and the number of photoreceptor nuclei is reduced. The space between the remaining photoreceptor nuclei and the retinal pigment epithelium is a processing artifact. In end-stage retinitis pigmentosa, there are no recognizable cell layers. The retina is reduced in thickness and cell number. A retina with this severe degeneration would be blind.
Source: Retinitis Pigmentosa and Stationary Night Blindness, The Online Metabolic and Molecular Bases of Inherited Disease
Citation: Valle D, Beaudet AL, Vogelstein B, Kinzler KW, Antonarakis SE, Ballabio A, Gibson K, Mitchell G. The Online Metabolic and Molecular Bases of Inherited Disease; 2014 Available at: Accessed: October 12, 2017
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