Dynamic visual acuity as an index of eye movement control

The dynamic visual acuity, DVA, of man and monkey was determined, and the associated horizontal eye movements were correlated with DVA. Monkeys have superior DVA, but inferior static visual acuity. The saccadic and smooth pursuit eye movements of monkeys are of shorter latency and higher velocity than those of man. Monkeys need only one saccade to attain a maximum smooth pursuit velocity of 140 deg/sec, whereas man needs two or more saccades to attain a smooth pursuit velocity of 90 deg/sec. It is probable that three factors determine DVA: (1) foveal visual acuity (2) oculomotor control (3) parafoveal visual acuity. It is shown that monkeys have better oculomotor control than man and it is inferred that monkeys have better parafoveal visual acuity. In addition it is demonstrated that monkeys, like man, are capable of predictive eye tracking.