Ocular findings in Niemann-Pick disease.

Light and electron microscopic studies of the eyes of a 3 1/2-year-old girl who died of Niemann-Pick disease disclosed accumulation of intralysosomal lipid material in all cells other than those that were pigmented. The nonpigmented layer of the ciliary process and the ganglion cells of the retina were especially involved. Electron microscopy revealed two main types of lipid cytosomes. The presumptive explanation for this finding is that the metabolism of the stored material in neurons differs from that in other cells. Topographic and structural studies of the pathologic pigment epithelium suggested that pigmented cells show storage material either when they are in intimate contact with affected cells or when the enzyme defect interferes with the catabolism of the outer segments.