Abstract
PURPOSE: The purpose of this study was to investigate the development of contrast sensitivity function (CSF) in children with intermittent exotropia (IXT) over 1 year and to explore the impact of surgical realignment on CSF. METHODS: A prospective study of 45 patients with IXT (aged 7-13 years) were matched with 30 healthy controls. Patients with IXT were categorized into the surgery group (n = 25) and the observation group (n = 20). Comprehensive ophthalmic examinations, including binocular and monocular CSF (measured by CSV-1000E), stereoacuity, and sensory fusion, were performed at baseline and the 1-year follow-up. RESULTS: At baseline, the IXT surgery group exhibited significantly worse area under the log contrast sensitivity function (AULCSF) and contrast sensitivity (CS) at several spatial frequencies (SFs) compared with the controls (P < 0.05). After 1 year, the control group demonstrated significant improvement in binocular AULCSF and CS at 3, 12, and 18 cycles per degree (cpd; P < 0.05). The surgery group showed significant gains in binocular AULCSF, CS at 3 cpd, and 18 cpd (P < 0.05), whereas the observation group exhibited no significant changes in any metric (P > 0.05). Three-way analysis of covariance (ANCOVA), adjusting for baseline CS, revealed significant main effects of the group, SF, and eye condition on CS change (all P < 0.001), with no significant interactions. Post hoc comparisons showed that the control group had the greatest improvement, followed by the surgery group; whereas the observation group remained lowest across most metrics. CONCLUSIONS: CSF is significantly impaired in children with IXT. The IXT may disrupt the normal development of contrast processing in children, whereas surgical realignment can partially reverse these effects. CSF assessment may provide valuable adjunctive information for the clinical management of pediatric IXT.