Invited Session I: Focusing on the Human Fovea: Active vision at the foveolar scale: Insights from fixational oculomotor behavior and retinal anatomy

Vision is an active process even at its finest scale in the 1-deg foveola, the visual system is primarily sensitive to changes in the visual input and it has been shown that fixational eye movements reformat the spatiotemporal flow to the retina in a way that is optimal for fine spatial vision. Using high-precision eye-tracking coupled with a system for gaze-contingent display capable of localizing the line of sight with arcminute precision, and an Adaptive Optics Scanning Laser Ophthalmoscope (AOSLO) for high-resolution retinal imaging enabling retinal-contingent manipulations of the visual input, our results show that the need for active foveolar vision also stems from the non-uniformity of fine spatial vision across this region. Further, we show that the visual system is highly sensitive even to a small sub-foveolar loss of vision and fixation behavior is readjusted to compensate for this loss. Overall, the emerging picture is that of a highly non-homogenous foveolar vision characterized by a refined level of control of attention and fixational eye movements at this scale.