Bull's-eye maculopathy, negative electroretinogram and low plasma cyclic guanosine monophosphate level. A report of two cases.

Two patients had bull's-eye maculopathy, negative electroretinograms and low level of plasma cyclic guanosine monophosphate. In these cases, single bright-flash electroretinograms were of a negative type and scotopic electroretinograms were reduced in amplitude, whereas photopic electroretinograms were normal or only slightly reduced in amplitude. The negative electroretinograms were considered to result from extensive abnormalities in the inner retinal layer or an abnormal cyclic guanosine monophosphate metabolism in the photoreceptor cells.