Visual acuity in the presence of retinal-image motion.

Resolution thresholds for Landolt C's and for vernier targets remain the same whether the target is stationary or moving with horizontal or vertical velocities of up to 2.5 degrees for foveal presentations lasting 0.1 and 0.2 s. Oblique target motions are tolerated only up to 1 degree. Because visual pursuit is ruled out by randomization of direction of motion and by the short exposure, it is concluded that a stationary retinal image is not a prerequisite for good acuity.