Detection and discrimination of the direction of motion in central and peripheral vision of normal and amblyopic observers

This paper describes the "motion" properties of the amblyopic fovea and compares them to the normal periphery. Specifically, thresholds for detection of the displacement of a grating pattern, and for discrimination of displacement direction were measured. The main findings of these experiments were: in the central vision of both normal and amblyopic observers, unreferenced displacement are detected with an accuracy equal to the observer's grating acuity; in the normal periphery, unreferenced motion thresholds fall off at a slower rate than does grating acuity; in amblyopic eyes, displacement thresholds are most elevated centrally; the addition of an abutting reference improves detection of motion for the normal fovea and in anisometropic amblyopes, but elevates motion thresholds in both the normal periphery and in the fovea of amblyopes with strabismus. The adequacy of the normal periphery as a model for the central vision of amblyopes is discussed.