MOVING VERNIER IN AMBLYOPIC AND PERIPHERAL-VISION - GREATER TOLERANCETO MOTION BLUR

The purpose of this study was to examine the hypothesis that higher st imulus velocities could be tolerated in amblyopic and normal periphera l vision, The basis for this hypothesis is that a shift in the spatial scale of processing appears to account for the degradation in vernier acuity for moving stimuli in normal vision, and, to a large degree fo r the degradation in vernier acuity for stationary stimuli in amblyopi c and peripheral vision, Vernier thresholds were determined using a pa ir of long abutting lines, for velocities ranging between 0 and 8 deg/ sec, Comparisons were made between non-amblyopic and amblyopic eyes in two amblyopic observers, and between central and peripheral (5 and 10 deg) vision in two normal observers, We analyzed our threshold vs vel ocity data using an equivalent noise analysis, and defined the knee of the function, the point at which vernier threshold is elevated by a f actor of root 2, as the ''critical velocity'' beyond which image motio n degrades vernier acuity, Critical velocities were found to be higher in amblyopic than in non-amblyopic eyes; and higher in peripheral tha n central vision, Our results are consistent with the predictions from the shift in spatial scale notion-that higher velocity of image motio n can be tolerated because of the shift-in sensitivity toward lower sp atial-frequency filter mechanisms in amblyopic and normal peripheral v ision. (C) 1997 Elsevier Science Ltd.