Clinical Features of Retinal Disease

Chloroquine toxicity

Cone dystrophy

Chloroquine toxicity (fluorescein angiography)

Stargardt disease

Clinical Features

Bull’s eye maculopathy refers to a pattern of retinal pigment epithelial alterations in the macula characterized by a central region of hyperpigmentation surrounded by a zone of hypopigmentation reminiscent of an aiming target. These alterations may be subtle clinically but are more prominent with fluorescein angiography. Bull’s eye maculopathy is usually bilateral but may be asymmetric. Patients may complain of reduced central acuity (particularly with reading), dyschromatopsia, and paracentral scotomas.

Differential Diagnosis

Conditions associated with bull’s eye maculopathy include cone dystrophy, rod-cone dystrophy, chloroquine/hydroxychloroquine toxicity, Stargardt disease, age-related macular degeneration, fenestrated sheen macular dystrophy, concentric annular macular dystrophy, and following intravitreal injection of fomivirsen sodium for cytomegalovirus retinitis. A “pseudo” bull’s eye maculopathy may be seen with pattern dystrophies, acute macular neuroretinopathy, chronic macular holes, and resolved unilateral acute idiopathic maculopathy.

CHERRY RED SPOT

Clinical Features

A cherry red spot refers to the macular appearance of a central red spot surrounded by superficial retinal whitening. It is seen most commonly after a central retinal artery occlusion. Occlusion of the central retinal artery results in ischemia and infarction of the inner retina including the nerve fiber and ganglion cell layers. This is manifest by whitening and edema of the inner retina in the macular area where the nerve fiber and ganglion cell layers are thickest. The foveola retains its reddish color because the inner retinal layers are displaced laterally and the underlying choroidal circulation remains intact. Retinal ischemia and infarction account for the cherry red spot observed in cases of intraocular gentamicin toxicity.

A cherry red spot may be observed in a group of neurometabolic storage disorders characterized by the accumulation of glycolipids and phospholipids in the ganglion cell layer of the retina. These disorders include Tay-Sachs disease (GM2 gangliosidosis type 1), Niemann-Pick disease, and cherry red spot myoclonus syndrome (sialidosis type 1). The accumulation of material is most evident in the macula, which contains multiple layers of ganglion cell nuclei. The lack of ganglion cells in the foveola accounts for the central red spot.

Differential Diagnosis

The most common conditions associated with a cherry red spot are central retinal artery occlusion, intraocular gentamicin toxicity, and metabolic storage diseases.

Central retinal artery occlusion

Intraocular gentamicin toxicity

Clinical Features

Chorioretinal folds are visualized most commonly in the posterior fundus. They may be unilateral or bilateral, depending on the etiology. Individuals may be asymptomatic or complain of blurred or distorted vision. Idiopathic chorioretinal folds are believed to be caused by scleral shrinkage. Scleral shrinkage decreases the surface area available to the overlying choroid and retina, resulting in chorioretinal folds. Individuals with idiopathic chorioretinal folds usually are asymptomatic, although some degree of hyperopia is common. Imaging studies reveal flattening of the posterior aspect of the globes.

Differential Diagnosis

In addition to idiopathic occurrences, chorioretinal folds may be associated with abnormalities of the optic disc including papilledema and optic disc drusen.

Chorioretinal folds are observed frequently with intraocular hypotony (usually in the setting of glaucoma surgery). When intraocular hypotony is prolonged, the folds may become permanent. Chorioretinal folds in the macula may be associated with posterior micro-

phthalmos and high hyperopia. Radial chorioretinal folds may be observed in exudative age-related macular degeneration (AMD) or other causes of choroidal neovascularization (CNV). Unilateral chorioretinal

folds may be associated with a retrobulbar tumor or inflammatory conditions such as posterior scleritis.