Postural stability and optic flow sensitivity following sight restoration from congenital bilateral cataracts

Vision is crucial for maintaining balance and facilitating locomotion. Optic flow, for example, provides key self-motion cues for navigation. Congenital blindness typically leads to increased postural sway and impaired navigation. Here, we investigated postural stability and optic flow sensitivity in individuals surgically treated for congenital dense bilateral cataracts years after birth. Experiment 1 assessed whether cataract-treated participants rely on vision to stabilize their stance with eyes open compared with eyes closed. Cataract-treated participants decreased their sway with open eyes to a lesser extent than controls, indicating a reduced ability to use vision for stabilization. Interestingly, participants tested longer after surgery showed less sway, suggesting partial learning in using vision to enhance stability. Experiment 2 assessed whether different radial and translational optic flow patterns elicit distinct effects on body sway, which would indicate illusory sensorimotor perceptions. We included typically sighted controls tested either with normal vision or with experimentally reduced visual acuity. While cataract-treated participants exhibited greater sway than controls, their sway was less influenced by optic flow patterns. Overall, the study showed that cataract-treated individuals exhibit partial learning in utilizing vision for stabilization and less pronounced illusory self-motion perception from optic flow compared to typically sighted individuals.