Eye movements were recorded while participants passively or actively perceived differently oriented square-wave gratings while fixating at a fixation dot. (a) The experiment presented eight differently oriented (0 to 180 degrees in steps of 22.5 degrees) square-wave (spatial frequency of 1.5 cycles per visual degree, 100% contrast) gratings (outer radius of 10.0 and inner radius of 1.5 visual degrees) presented on a mean-luminance grey background. Throughout the entire experiment, participants were instructed to maintain fixation at a fixation dot (outer radius of 0.1 visual degrees). (b) Each of twelve runs of the passive session started with 8 seconds of fixation and finished with 8 seconds of fixation. In between, sixteen 7-second trials were presented with 1 second inter-trial interval. A trial presented one oriented grating at 2 Hertz (i.e., 250 ms ‘on’, 250 ms ‘off’), where each ‘on’ period presented the grating with a uniform random phase. (c) The active session was similar to the passive session, but on 12.5 percent of trials one ‘on’ period within a trial presented the oriented grating with a 10 degree perturbation (clockwise or counter-clockwise). Participants were instructed to detect these perturbed trials upon which they had to press a button.