Orthoptic Treatment After Strabismus Surgery in Child Intermittent Divergent Strabismus

Purpose: To evaluate short-term motor and sensory-motor outcomes following postoperative OT in children with IXT after strabismus surgery. Methods: This prospective before-after observational study included children with IXT who underwent bilateral lateral rectus recession and were referred for postoperative OT based on predefined clinical criteria. A structured 12-week OTplan was initiated approximately six months after surgery. Outcome measures included angle of deviation (prism diopters, PD), near point of convergence (cm), positive fusional vergence amplitudes (PD), and convergence amplitudes at distance and near (PD). Pre- and post-therapy changes were analysed using paired-samples t-tests with effect sizes calculated using Cohen's d. Final postoperative alignment was additionally compared cross-sectionally between children who underwent OT and those managed without OT. Results: Eighty-eight children had complete paired motor and sensory-motor data and were included in the analyses. Changes in static ocular alignment were small, with mean residual deviation improving from -7.02 ± 6.91 PD to -5.22 ± 6.60 PD after OT (mean change +1.80 PD; p < 0.01; d ≈ 0.30). No significant difference in final postoperative alignment was observed between the OT and non-OT groups (p = 0.827). In contrast, marked improvements were observed in sensory-motor outcomes. Positive fusional vergence amplitude increased from 7.30 ± 8.33 PD to 22.19 ± 9.26 PD (p < 0.001; d ≈ 1.5). Distance convergence amplitude improved from 7.30 ± 8.33 PD to 22.19 ± 9.26 PD, and near convergence amplitude from 10.95 ± 12.50 PD to 33.29 ± 13.89 PD (both p < 0.001; d ≈ 1.5). Near point of convergence showed a modest but significant improvement. Conclusions: Postoperative OT was associated with substantial short-term improvements in sensory-motor function, particularly fusional and convergence capacities, while changes in static ocular alignment were small and of limited clinical relevance. These findings support the role of OT as a functional adjunct to surgery, aimed at enhancing binocular control and postoperative sensory-motor stability in children with IXT.