Visual evoked responses in diabetes.

In view of the conflicting evidence concerning prolongation of the VERs in diabetes, pattern reversal VERs were performed on 60 diabetic inpatients. Only in one patient was the VER unequivocally delayed without some other explanation and in 2 other patients it was prolonged in association with proliferative retinopathy. In the latter instance the latency may have been increased by involvement of the maculo-papillary fibres of the optic nerve which may occur during their passage through the retina. Otherwise the study does not strongly support the concept of optic neuropathy or central encephalopathy of the visual system in diabetes, at least as far as can be demonstrated by visual evoked cortical responses to pattern reversal stimuli.