The Negative Directional Aftereffect Associated with Adaptation to the Prismatic Effects of Spectacle Lenses

Purpose To determine whether subjects would demonstrate a negative directional aftereffect in a sparse visual environment after being trained to point accurately through a spectacle lens. Methods Subjects were made myopic using a contact lens and then the myopia was corrected with a spectacle lens. Pointing behavior was used to assess directional localization. Training was carried out by showing subjects their pointing errors. Results Seven of 10 subjects demonstrated a negative directional aftereffect after spectacle lens adaptation. Conclusions The presence of a negative directional aftereffect indicates that some patients who switch between spectacles and contact lenses can accurately localize objects only in one condition. Patients who do not demonstrate a negative directional aftereffect may be able to correctly localize objects with both spectacles and contact lenses.