Adaptation and counteradaptation to complex optical distortion

The optical distortion caused by wearing a facemask in water magnifies the angular size of objects and reduces their optical distance. However, objects generallyappear to be further than their optical distance, with the result that points in the left part of the visual field are apparently displaced to the left, and those on the right to the right. Experiments on hand-eye coordination under water showed that adaptation to one aspect of the distortion produced some counteradaptation to complementary aspects: adaptation to distance produced increased lateral distortion, and adaptation to one side of the lateral distortion produced increased distortion on the opposite side. Nevertheless, “trading” was incomplete, and some overall adaptation of the visual metric occurred.