ADAPTING TO MONOCULAR VISION - GRASPING WITH ONE EYE

The aim of the present study was to determine whether normal subjects with one eye covered and patients in whom one eye had been enucleated generate more head movements than subjects using binocular vision duri ng the performance of a visually guided grasping movement. In experime nt 1, 14 right-handed normal subjects were tested binocularly and mono cularly in a task in which they were required to reach out and grasp o blong blocks of different sizes at different distances. Although the t ypical binocular advantage in reaching and grasping was observed, the overall head movement scores did not differ between these testing cond itions. In experiment 2, seven right-handed enucleated patients were c ompared to seven age and sex-matched control subjects (tested under bi nocular and monocular viewing conditions), on the same task as used in experiment 1. While no differences were found in the kinematics of re aches produced by the enucleated patients and the control subjects, th e patients did produce larger and faster resultant head movements, com posed mainly of lateral and vertical movements. This suggests that enu cleated patients may be generating more head movements in order to bet ter utilize retinal motion cues to aid in manual prehension.