Diffuse Photoreceptor Dystrophies

Inherited dystrophies that affect the rods and cones are discussed in greater detail in BCSC Section 12, Retina and Vitreous. Only the most common photoreceptor dystrophy, retinitis pigmentosa (RP), is discussed here.

Figure 11-37 Polypoidal choroidal vasculopathy. A, Fundus photograph reveals elevated, red-orange, nodular subretinal lesions in the peripapillary area. B, Fluorescein angiogram (60 seconds) on the left shows mildly hyperfluorescent polypoidal lesions (arrow), which are best seen on the indocyanine green (ICG) angiogram on the right (arrow). Hypofluorescent areas on the fluorescein angiogram (arrowhead) and ICG angiogram (arrowhead) are due to hemorrhage. C, OCT from the same patient shows an elevated sub-RPE lesion in the peripapillary region with associated intraretinal and subretinal fluid.

(Courtesy of Robert M. Carroll, MD.)

Figure 11-38 Stargardt disease. A, Fundus photograph shows diffuse retinal flecks. B, FAF imaging reveals increased autofluorescence corresponding to the retinal flecks (red asterisk) and decreased autofluorescence corresponding to areas of RPE atrophy (green asterisk).C, SD-OCT image shows hyperreflectivity at the level of the RPE (corresponding histologically with enlarged RPE cells with increased lipofuscin content) (arrows), markedly thinned retina in the foveal region, and focal attenuation or loss of the photoreceptor cell layer in areas corresponding to RPE atrophy (area between arrowheads).D, Photomicrograph of a PAS-stained section demonstrates hypertrophic RPE cells (arrowheads) with numerous PAS-positive cytoplasmic granules containing lipofuscin (asterisks). This histologic finding corresponds to the retinal flecks seen clinically. E, In advanced stages of Stargardt disease, geographic RPE atrophy with loss of the photoreceptor cell layer (between arrows) may be noted.

(Parts A–C courtesy of Tomas S. Aleman, MD; parts D and E courtesy of Sander Dubovy, MD.)

Figure 11-39 Adult-onset foveomacular vitelliform dystrophy. A, Fundus photograph shows a yellowish, egg yolk–like lesion with focal pigment clumping and mottling in the central macula. B, Near-infrared FAF image from the same patient shown in part A reveals increased autofluorescence corresponding to the vitelliform lesion (arrow).C, SD-OCT (same patient as in parts A and B) reveals subfoveal hyperreflective material (asterisk). Note the irregular RPE elevation (between arrowheads).D, Histologic findings include pigment-containing cells in the subretinal space (arrowheads) and outer neurosensory retina (arrow).E, Electron microscopy shows pigment-containing cells filled with lipofuscin (arrowheads).

(Parts A–C courtesy of Tomas S. Aleman, MD; parts D and E courtesy of Sander Dubovy, MD.)

Figure 11-40 Retinitis pigmentosa. A, Fundus photograph shows pallor of the optic nerve, retinal arteriolar narrowing, focal depigmentation, and bone-spicule pigmentation in the peripheral fundus. B, Histologically, marked photoreceptor cell loss (between red arrowheads) and RPE migration into the retina in a perivascular distribution (black arrows) are apparent and correspond to the bone-spicule–like pattern seen clinically. The retina is artifactitiously detached from the underlying RPE and choroid (asterisk).

(Part A courtesy of Tomas S. Aleman, MD.)

RP refers to a group of inherited retinal diseases characterized by RPE and photoreceptor dysfunction and degeneration, resulting in progressive visual field loss. The genetics of RP are complex: it can be sporadic, autosomal dominant, autosomal recessive, or X-linked. Mutations in the rhodopsin gene (RHO) are the most common cause of autosomal dominant RP.

The term retinitis pigmentosa is a misnomer because clear evidence of inflammation is lacking. Ophthalmoscopic findings include pigment arranged in a bone-spicule–like configuration around the retinal arterioles, arteriolar narrowing, and optic nerve head atrophy (Fig 11-40A). The disease is characterized primarily by the loss of rod photoreceptor cells via apoptosis. Cones are seldom directly affected; however, they degenerate secondary to the loss of rods. Microscopically, loss of photoreceptor cells is seen, as well as RPE migration into the neurosensory retina around retinal vessels (Fig 11-40B). The arterioles, though narrowed clinically, show no histologic abnormality initially. Later, thickening and hyalinization of the vessel walls develop. The optic nerve may show diffuse or sectoral atrophy, with gliosis as a late change.

Excerpted from BCSC 2020-2021 series: Section 4 - Ophthalmic Pathology and Intraocular Tumors. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.