Fig 1.
Experimental timeline and set-up.
A. Trial timeline of computer-based DVA test. Each trial starts with peripheral fixation, followed by step-ramp stimulus motion; target is a Landolt-C ring. Observers performed a judgment about the location of the gap in the “C” (one of 4 locations) at the end of each trial via button press. B. Set-up for computerized dynamic-object DVA test and eye tracking. C. Set-up for clinical static-object DVA test.
Fig 2.
A. Proportion correct in dynamic visual acuity task as a function of gap size for n = 23 observers; n = 11 were junior players (open symbols) and n = 12 were senior players (filled symbols). Speed is denoted by color, seniority by line type; error bars are standard errors of the mean. B. Relation between static visual acuity (binocular ETDRS) and dynamic-object DVA at slow and fast speed. Lines are best fit linear regressions. C. Relation between static-object and dynamic-object DVA in degrees of visual angle.
Fig 3.
Eye movement responses in dynamic-object DVA task.
Eye position (left column) and eye velocity traces (right column) as a function of time from three different trials for a stimulus moving at 70 deg/s; all traces obtained from representative observer #16. Dotted red line denotes target trajectory: peripheral fixation at 5 deg from screen center, target step, target ramp, DVA stimulus onset at time when stimulus reaches fovea, 120 ms after ramp onset. Horizontal eye position in black, vertical eye position in blue. Smooth components marked in green, saccades marked in magenta. A,B. Trial with smooth pursuit (green) following target onset. C,D. Trial with a large, early catch-up saccade (magenta) following target onset. E,F. Trial with a reverse saccade towards the target step, i.e., in the opposite direction to target motion.
Table 1.
Effects of speed on smooth pursuit eye movements.
Shown are means and standard deviations for slow and fast speed and results of repeated-measures ANOVA with speed as factor.
Fig 4.
Correlations between perceptual DVA thresholds and eye movement parameters.
Dynamic-object DVA thresholds are given in degrees of visual angle; results are for n = 21 observers with available eye movement data. Each data point is one observer in a given category; speed is denoted by color. Lines denote best linear fits. A. Eye velocity latency (ms). B. Eye velocity gain. C. Minimum position error (deg). D. Cumulative saccade amplitude (deg). E. Proportion of trials with reverse saccade.