Observation of a temporary change in the perceived orientation of lines after having adapted to lines tilted in another direction. If, for example, you stare at white and black bars tilted to the left for a minute or so, then look at vertical bars, these will now appear to tilt slightly to the right. This is an example of the adaptation of orientation-specific cells in the visual system which become fatigued and therefore temporarily less responsive. See adaptation; waterfall after-effect; orientation-specific cell.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann