Visual and vestibular functioning, and age and surgery effects on postural control in healthy children with vertical strabismus

Abstract

Purpose: To describe visual and vestibular functioning and the effects of age and surgery effects on postural control in healthy children with vertical strabismus. Design: This is a comparative case series. Methods: We evaluated participants at the Scientific Institute Eugenio Medea during routine clinical activities. We enrolled 30 consecutive children/adolescents (age range 4–13 years) with isolated vertical strabismus, with and without corrective surgery. Participants were split into four subgroups according to age (4–8 years versus 9–13 years) and ocular surgery (surgery versus no surgery). The clinical protocol included ophthalmological, orthoptic, neurological, physiatrical, otolaryngological, and vestibular evaluations, and the instrumental protocol included ocular cyclotorsions assessment, posturography, and vestibular myogenic-evoked potentials. Main outcome measures of the study were the prevalence of study-relevant orthopedic, ocular, vestibular, and posturographic abnormalities. Results: Among the overall largely variable findings across patients’ groups, we found some interesting trends: larger binocular vision and convergence disorders in younger children, smaller prevalence of asymmetric vestibular-evoked potentials in operated children, less posturographic abnormalities in younger children. No clear-cut beneficial effect of surgery was found on all clinical and instrumental parameters considered, despite good re-alignment of the eyes. Conclusion: The pathophysiology of postural control in vertical strabismus is extremely complex and above the potential of this study design and should be specifically addressed in deeper experimental studies.