What one sees depends on how far the eye has moved.

Humans explore visual scenes through frequent, rapid gaze shifts known as saccades. These movements redirect the high-acuity region of the retina toward objects of interest, thus selecting information based on location. Here, we show that saccade amplitude provides a separate and complementary form of selection, effectively filtering visual information by spatial frequency rather than location. Building on analyses of the resulting visual input signals, we examined how pattern visibility was influenced by the size of the preceding saccade. A reduction in saccade amplitude attenuates post-saccadic visual sensitivity in an amplitude-dependent range of low spatial frequencies. This effect is highly robust, so that even small changes in saccade size considerably affect visibility. We show that this phenomenon arises from the way that the magnitude-dependent kinematic characteristics of saccades transform the visual world into a spatiotemporal flow. That is, post-saccadic visibility closely follows theoretical predictions based on the spatial information that saccade transients convey within the temporal bandwidth of retinal sensitivity. Thus, saccades not only guide selection based on location, but also filter visual information based on scale, actively shaping perception.