Abstract
Abstract: :
Purpose: The objective of this study was to calculate the geometric relationship between an area of distortion on the Amsler Grid Test to the corresponding area of an average human face at various viewing distances. The overall objective was to develop an alternate use for the Amsler Grid Test in predicting the social functioning abilities of patients with central visual distortions, as determined by their abilities for facial recognition. Methods:A simple geometric relationship was used to calculate the area of retinal distortion affected by one Amsler Grid Square (AGS), measuring twenty five square–millimeters, viewed from thirty centimeters distance, with the corresponding area of a human face viewed from a one, three or six meters distance. The geometric calculations were then applied to previously reported facial recognition data to determine whether or not the face would be recognizable given the area covered by the distortion. Results:An area of central visual distortion affecting one AGS (viewed at thirty centimeters distance) could potentially lead to complete inability to recognize a human face at six meters distance. Likewise, a face at three meters distance may be unrecognizable with a distortion area affecting two AGS, and a face at one meter may not be recognized with a distortion area affecting seventeen AGS. Conclusions: Patients with one or more AGS of distortion are at risk for impaired facial recognition at distances of usual interpersonal interaction, thereby negatively affecting their social functioning.
Keywords: face perception • aging: visual performance • vision and action