Re-alignment of the eyes, with prisms and with eye surgery, affects postural stability differently in children with strabismus.
OBJECTIVE
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.
Laboratoire de Psychologie et Neuropsychologie Cognitives, FRE 3292 CNRS IUPDP Université Paris Descartes, 71 Avenue Edouard Vaillant, 92774 Boulogne Billancourt Cedex, France.
Agathe
A
Legrand
Emmanuel
E
Bui-Quoc
Maria Pia
MP
Bucci
D000221:Adaptation, Ocular / Q000502:physiology; D000293:Adolescent; D002648:Child; D005139:Eyeglasses; D006801:Humans; D009801:Oculomotor Muscles / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures; D004856:Postural Balance / Q000502:physiology*; D013285:Strabismus / Q000503:physiopathology* / Q000628:therapy*; D014787:Vision Tests; D015348:Vision, Binocular / Q000502:physiology*; D014792:Visual Acuity / Q000502:physiology; D014796:Visual Perception / Q000502:physiology