Lauren Hoare¹, Krista Kelly¹; ¹University of Waterloo

Introduction: Coordination between the eyes and body is important for navigating the environment. Children with disrupted binocular vision from strabismus and amblyopia score lower for walking on a standardized test of motor ability (Kelly et al., 2018 IOVS). However, standardized tests do not assess gait kinematics during walking. Here, we investigated the development of gait kinematics during walking in children with impaired binocularity compared to controls. Methods: 9 children ages 7-13 years with impaired binocularity (stereoacuity, 3.0±0.8 log arcsecs) due to strabismus or amblyopia and an age-similar group of 18 controls were enrolled. Children walked the length of a GAITRite pressure-sensitive walkway and completed 3 conditions of varying complexity: 1) Straight Walk (W): walk on mat, 2) Isolated Target Walk (I): walk and step on two-dimensional targets, and 3) Distractor Target Walk (D): walk and step on two-dimensional targets while avoiding two-dimensional distractors. Gait kinematic outcomes were normalized velocity (leg lengths/second), step time (msecs), and accuracy (%) of stepping on targets or avoiding distractors. Results: Controls were faster during straight walk compared to the other two conditions (normalized velocity, W:1.49±0.23, I:1.42±0.24, D:1.38±0.25 leg lengths/sec; longer step time, W:508±52, I:522±48, D:525±51 msecs, ps≤0.011). Children with impaired binocularity showed the same pattern (normalized velocity, W:1.67±0.35, I:1.58±0.29, D:1.50±0.27 leg lengths/sec; step time, W:468±63, I:494±61, D:491±56 msecs, ps≤0.06). While there were no group differences for velocity or step time (all ps≥0.089), children with impaired binocularity were less accurate than controls when stepping on targets, especially when paired with distractors (90.0±12.5% vs 98.2±3.0%, p=0.015). Conclusions: Impaired binocularity in children did not influence walking speed but impacted accuracy, especially with a more complex task. Impaired binocularity early in life may impact gait by causing visual uncertainty as children walk or may result in the development of compensatory strategies that are less effective during navigation.

Acknowledgements: NSERC RGPIN-2024-03992