Re-alignment of the eyes, with prisms and with eye surgery, affects postural stability differently in children with strabismus.

Aim: The purpose of the study was to examine the effect of eye re-alignment (after wearing prisms and after eye surgery) on postural stability in children with strabismus.

Methods: Nine children with strabismus (6-13 years old) participated in the study. A posturography platform (TechnoConcept) was used to examine posture in quiet stance at two distances: steady fixation of a target at near distance (40 cm) and at far distance (200 cm). Four different conditions were tested: with and without prisms before eye surgery, and twice after eye surgery.

Results: The surface of the CoP increased after wearing prisms (540 mm(2) compared to the condition without prisms (462 mm(2)); in contrast, eye surgery reduced the surface of the CoP, leading to improved postural control (454 mm(2) and 401 mm(2), respectively, in the post 1 and post 2 surgery condition). Unlike normal children, strabismic children showed no improvement in postural control at near distance.

Conclusions: Binocular visual and motor changes affect body sway; adaptive mechanisms induced by eye re-alignment after surgery allow improved postural control. The absence of dependency on distance in postural stability in strabismic children could be due to their impaired depth perception and to the poor integrity of the visual signal required to control posture.