Contribution of stereopsis, vergence, and accommodative function to the performance of a precision grasping and placement task in typically developing children age 8-14 years

Abstract

Upper limb reaching and grasping movements are performed more efficiently during binocular viewing; however, the distinct contribution of stereopsis, fusional vergence, and accommodation (binocular facility, amplitude and accuracy) has not been examined in typically developing children. This study examined binocular visual function in a cohort of 57 typically developing children, 8 to 14 years old. Hand kinematics were recorded using a motion capture camera while children performed a prehension task involving threading a bead onto a needle. Results showed that different aspects of binocular vision contribute to the control of distinct phases of upper limb movements. Specifically, fusional vergence was associated with higher peak reach velocity, stereoacuity was associated with shorter grasp execution, and accommodation was associated with shorter placement duration. These findings suggest that different aspects of binocular vision play an important role in optimizing the control of distinct phases of prehension movements during development.

Keywords: Accommodation; Binocular vision; Development; Fusional vergence; Kinematics; Reaching and grasping; Stereoacuity.