Development of a binocular advantage for the performance of complex manipulation skills in healthy children 5 to 13 years old

Abstract

Purpose: Individual studies have shown that visuomotor coordination and fine stereopsis continue to improve in normally developing children from birth to early teenage years; however, no study has systematically addressed the relationship between the development of stereopsis and fine manipulation skills. Therefore, the aim of this study is to examine the significance of binocular vision by comparing monocular and binocular viewing in the performance of complex manipulation tasks.

Methods: Seventy children (5-13 years old) with normal visual acuity (0.0 logMAR) and stereoacuity (range: 25-100 arc sec) were tested. Children performed 2 manipulation tasks: peg board and bead threading under randomized viewing conditions (binocular, right and left eye monocular). The main outcome measure was movement time to complete the task. Binocular summation ratio was calculated to determine the relative advantage in motor performance between binocular and monocular viewing.

Results: Age and stereoacuity were significant predictors for movement time during binocular viewing in the bead threading task (R²=0.44), while age was the only significant predictor for movement time in the peg board task (R²=0.46). The binocular summation ratio for the bead threading task also indicated that older children relied on binocular vision more than younger children (5-6 years old: 0.896; 7-8 years old: 0.879; 9-13 years old: 0.792). Results from the multiple regression analysis for the bead threading task revealed a 7.3% variance in the binocular summation ratio was explained by age and 3.6% was due to stereoacuity (p<0.05). In contrast, binocular summation ratio was close to 1 for the peg board task and there was no significant difference in movement time between binocular and monocular viewing in children in different age groups (5-6 years old: 1.086; 7-8 years old: 1.01; 9-13 years old: 0.944). Thus, fine stereopsis is an independent predictor of performance on a complex manipulation task; however, the extent of binocular advantage is dependent on the task.<br />

Conclusions: This research shows that 9-13 year-old children have a greater binocular advantage during performance of a complex manipulation task which requires precision grasping and object placement. Thus, the bead threading task offers a more sensitive assessment of the role of binocular vision in development of fine manipulation skills.