Visual evoked potentials in the evaluation of “cortical blindness” in children

Visual evoked responses (VERs) to brief light flashes were recorded from occipital regions in a group of 30 “cortically blind” children aged 4 months to 15 years and were compared with those of 31 children of similar age range who had the same type of central nervous system diseases but without signs or symptoms of blindness. The VERs were analyzed for amplitude, number of peaks, and morphology, follwing a method used previously by other authors. All the responses had some degree of abnormality, but there were no significant differences between the two groups. The findings suggest that recording of VERs is not always an accurate method for diagnosis of cortical blindness in children since the presence of abnormal responses in not incompatible with normal vision. Only 1 patient with cortical blindness showed no response.