Monovision: Consequences for depth perception from small and large disparities

Monovision correction of presbyopia reportedly degrades stereoacuity. However, effects of monovision on disparity sensitivity throughout the range of useable disparities have not been studied. This thesis studied the short-term effects of induced monovision on a depth-discrimination task over a range of disparities.;Depth-discrimination was impacted more with monovision at the 3 m compared to 62 cm viewing distance. This indicates that there is a more severe disruption in stereopsis at the fixation distances typical during walking.;Young participants tended to accommodate to minimize blur in one eye at the expense of blur in the other. In contrast, older participants would have experienced roughly equivalent blur in the two eyes. Despite this difference both groups displayed similar detrimental effects of monovision.;Monovision degraded discrimination of small disparities but had less effect on accuracy in the large disparity range. Thus, stereopsis from large disparities may be more resistant to interocular image differences.