Presaccadic attention sharpens visual acuity

Visual perception is limited by spatial resolution, which declines with eccentricity and differs around polar angle locations. To compensate for poor peripheral resolution, we make rapid eye movements -saccades- to bring peripheral objects into high-acuity foveal vision. Already before saccade onset, visual attention shifts to the saccade target location and prioritizes visual processing. This presaccadic shift of attention improves performance in many visual tasks, but whether it changes resolution is unknown. Here, we investigated whether presaccadic attention sharpens peripheral spatial resolution; and if so, whether such effect interacts with polar angle locations. We measured acuity thresholds in an orientation discrimination task during fixation and saccade preparation around the visual field. The results revealed that presaccadic attention sharpens acuity, which can facilitate a smooth transition from peripheral to foveal representation. This acuity enhancement is similar across the four cardinal locations; thus, presaccadic attention does not change polar angle differences in resolution.