Abstract Natural scenes contain a huge amount of information if counted by spatial pixels and temporal frames. However, most of the information is redundant because the pixels and the frames are highly correlated. The optical flow, generated by motions of the objects and the observer, contributes significantly to the statistical regularity of such spatiotemporal correlations. The visual system of an animal such as the human is highly adapted to this statistical regularity such that the visual sensitivity follows the same contours as the spatiotemporal correlations of natural scenes in motion, in particular, along two axes: space and motion instead of space and time. Furthermore, vision is an active process, during which eye movements interact with visual scenes and select images that arrive on the retina: pursuits and fixations on objects significantly alter the image velocity distributions on the fovea and the periphery, which lead to the dependence of the visual sensitivity on the retinal eccentricity; saccades between objects change the natural scene statistics dynamically, which lead to the dependence of the visual sensitivity on the time relative to saccades. All of these can be accounted for by the proposed ecological theory that the visual system maximizes the causal information of the natural visual input. (In: Dynamics of Visual Motion Processing (Ilg UJ and Masson GS eds), Page 261-282, doi:10.1007/978-1-4419-0781-3_12, 2009)