Eye-hand coordination during a precision grasping and placement task in children with a history of amblyopia

Eye-hand coordination is a key aspect of visuomotor control essential for performing most daily activities. Disruption in visuomotor control, characterized by slower arm movements and grasping errors, has been documented in children with amblyopia. This study aimed to characterize the effects of amblyopia on the temporal pattern of eye and hand coordination during the performance of a task that involves reaching, precision grasping, and placement. The study recruited 28 children with a history of amblyopia and 56 typically developing peers (age range 6-14 years). Children performed a bead-threading task while their eyes and hand movements were recorded concurrently. As hypothesized, children with amblyopia demonstrated poorer task performance, with greater deficits for the object manipulation compared to the reaching (transport) components. In comparison to their peers with normal vision, children with amblyopia had shorter reaction time for initiating eye and hand movement, longer object fixation duration to guide grasp execution and object placement, and lower eye-hand latency difference for the second movement indicating that the hand movement preceded eye initiation. These results suggest that children with amblyopia have poorer motor planning ability, which impacts movement execution. Longer fixations during object manipulations indicate that more time is required to transform the noisy visual input into a motor response. Overall, the study adds to the growing body of evidence highlighting deficits in visuomotor control in amblyopia.