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Abstract
All cats fed a specific semipurified diet developed a retinal degeneration. In the early stages electroretinograms (ERG's) from both the cone and rod systems were reduced in amplitude; those from the cone system were delayed in implicit time while those from the rod system were normal in implicit time. These ERG changes, as well as the findings on ophthalmoscopic and light microscopic examination, were consistent with the idea that initially widespread areas of cones and localized areas of rods were abnormal. In moderately advanced stages rod-implicit times were also delayed, and the slope of the function describing log stimulus intensity vs. rod ERG amplitude was abnormal; these recordings indicated that rod involvement had also become extensive. No signs of vitamin A deficiency were observed. Similarities between this retinal degeneration in the cat and retinal degenerations in man are discussed.