CROWDING IN VISUALLY-IMPAIRED PATIENTS - CONTOUR INTERACTION AND OR GAZE-SELECTION DEFECTS/

Visual crowding, defined as a lower line acuity compared to single-let ter acuity, was investigated in 18 visually impaired patients. The sep arate effects of contour interactions and gaze-selection defects were investigated using a line-acuity test, a single-letter acuity test, an d the Regan repeat-letter test. The limits of normality were establish ed from data collected on 25 age-matched normals. In the visually impa ired group, 83% of the patients showed visual crowding. When dividing the group into the other two categories, 39% of patients showed gaze-s election problems and 56% demonstrated abnormal contour interactions. Only 5% of the patients showed no effect of contour interactions or ga ze-selection defect. These results have important implications for the visual rehabilitation of such patients.