Quantitative analysis of retinal outer segments in ovine ceroid-lipofuscinosis.

Isolated outer segments from the photoreceptors of the eye were markedly reduced in young animals with ovine ceroid-lipofuscinosis. At 5 months of age, 68% of these structures were lost and by 18 months, no segments remained. Our results suggest that loss of these structures can be identified earlier by quantitative analysis, than by electroretinography.