Effects of interocular blur suppression ability on monovision task performance.

Suppression of anisometropic blur induced by monovision contact lenses was examined in 18 presbyopic subjects. Suppression ability was quantified by reducing the contrast of a bright test target, viewed by subjects wearing a monovision correction, until the blurred image was suppressed. Subjective success with monovision was evaluated using a patient survey and no correlation to blur suppression ability was found. Objective success was evaluated in terms of performance at three near work tasks, each requiring a different level of stereoscopic localization. A significant correlation was found between card filing performance (requiring a moderate level of stereopsis) and blur suppression ability. Correcting either the dominant or non-dominant eye for near in the monovision correction did not significantly affect blur suppression ability. There was no evidence for adaptation to monovision in terms of increasing blur suppression ability over time.