the changes that occur in the visual system itself or in visual perception as a result of continuous stimulation. For example, the range of light intensities over which photoreceptors are responsive changes with prolonged exposure to dark, and many visual aftereffects are caused by adaptation of neurons within the visual system. See also dark adaptation; light adaptation.
n. an inflammation of the pancreas, marked by severe abdominal pain and caused by biliary tract disorders (e.g., gallstones), alcoholism, viral infection, or reactions to certain drugs (e.g., some antipsychotic agents).