Patients with Alzheimer's disease (AD) reportedly exhibit greater pupillary dilation than healthy subjects in response to tropicamide. By means of videopupillography, we have found that the average basal pupillary diameter was greater in AD patients than in normal controls and that there is an inverse relationship between the average pupillary diameter and the maximal dilation obtained following tropicamide application in both groups. Pupillary response to tropicamide and videopupillography do not distinguish between Alzheimer's patients and controls.