Experience-dependent long-term facilitation of skew adaptation.

Adaptation to changes in the environment allows the visual system to achieve optimal perception in a continuously changing visual world. One particular example regarding recurrently encountered changes in everyday vision is geometrical distortions of the environment when wearing spectacles for vision correction, e.g., image shear by skew geometric distortions in progressive additional lenses. For optimal visual performance, it would be beneficial if the visual system uses previous history of recurrent distortions and learns to adapt fast when they are reapplied, yet this has not been systematically shown. The present study evaluates experience-dependent long-term facilitation of fast adaptation to image skew, i.e., a shear from the x- and y- axis, using ecological stimuli. Immediate and long-term facilitation of fast adaptation induced by minutes time scales of extended skew exposures was tested. Fast adaptation was quantified via the magnitude of perceptual bias after a brief exposure to image skew in a constant stimulus procedure. Immediate facilitation was tested by comparing the magnitudes of fast adaptation that are measured on the same day before, i.e., baseline, and after extended skew exposure. The retention of the facilitation was evaluated by comparing the fast adaptation measured after, on average, 57 days of the previous extended skew exposure with the baseline. After one hour of skew exposure, the amount of fast adaptation significantly increased from the baseline measurement indicating immediate facilitation of the fast adaptation. This facilitation was retained at, on average, 57 days after the extended exposure. Thus, the results depicted experience dependent long-term facilitation of skew adaptation that potentially explains visual habituation to distortions of spectacles.