In this project, we investigate whether and when motion becomes invisible when objects move across the retina. We manipulate the movement speed of the objects to mimic the peak velocity that objects have on the retina during saccades. We use a curvature discrimination task to assess observers' ability to detect the motion. We also assess saccadic peak velocities, which differ across individuals, their level of alertness, as well as for different saccade directions. We predict that motion thresholds for objects moving a certain amplitude covary with peak velocities of saccades that cause comparable intra-saccadic speeds of objects on the retina. In this experiment, we are going to focus on a small number of participants running in a large number of trials and movement amplitudes (6 sessions per participant).