Individual differences in eye drift predict visual acuity

Visual acuity is essential for daily activities. It is believed that optics and anatomy alone determine the limits of visual resolution. However, in addition to these factors, eye movements greatly contribute to input dynamics, as the eyes jitter incessantly during fixation, displacing stimuli over many photoreceptors. Here we examined the relation between this motion (ocular drift) and differences in visual acuity in emmetropic observers. We show that: (a) large individual variability exists in the characteristics of ocular drifts; (b) these differences profoundly affect the structure of spatiotemporal signals to the retina; and (c) the spectral distribution of the resulting input signals strongly correlates with visual acuity. Building on these findings, we further show that individual acuity differences can be predicted from the motor behavior elicited by a simple fixation task, without directly measuring acuity. These results shed new light on how oculomotor behavior contributes to individual variability in acuity. ### Competing Interest Statement The authors have declared no competing interest.