CEREBROMACULAR DEGENERATION

Genetically determined (autosomal recessive) neuronal lipid storage disease of the brain may affect the neural elements of the retina as well. The clinical forms are classified by the age at onset and the enzyme deficiency. The pathologic changes are present prenatally. Clinical manifestations occur as a critical level of intraneuronal lipidosis is reached, resulting in a progressive disease with dementia, visual disturbances, and neuromotor signs. A definitive diagnosis can be established readily by conjunctival biopsy, rectal biopsy, or appendectomy showing ganglioside accumulation even before clinical signs are present.

The striking ocular finding of a cherry-red spot in the macula is seen in congenital and infantile cases. A halo occurs from loss of transparency of the ganglion cell ring of the macula, which accentuates the central red or the normal choroidal vasculature. A cherry-red spot will occur in central retinal artery occlusion, sphingolipidosis, mucolipidosis, commotio retinae, and methanol toxicity. The sphingolipidoses include Niemann-Pick disease type A and type B, Tay-Sachs disease, Sandhoff's disease, neuronal ceroid lipofuscinosis, and generalized gangliosidosis. Optic atrophy will occur early in Tay-Sachs disease, and the cherry-red spot can be pigmented in dark retinas.

Extraocular muscle involvement can occur in juvenile sphingolipidoses, Refsum's disease, and beta-lipoproteinemia, the latter two disorders being associated with retinitis pigmentosa.

10.1036/1535-8860.ch14

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