Clinical Outcomes of Individualized Office-Based Vision Therapy for Intermittent Exotropia: A Retrospective Cohort Study

Vision therapy (VT) has been proposed as a nonsurgical treatment option for intermittent exotropia (IXT), although evidence regarding the optimal treatment dosage remains limited. This study aims to investigate the relationships between VT dosage and baseline demographic and clinical characteristics of treatment outcomes in IXT. Patients with IXT who underwent office-based VT between July 2020 and March 2024 at Changsha Aier Eye Hospital were included. Treatment outcome was classified as functional recovery (yes/no), defined by prespecified thresholds for fusion on the Worth Dot test (33 cm, 1 m, and 3 m), stereoacuity (distance and near), and convergence amplitudes. Binary logistic regression was used to evaluate associations between baseline characteristics and VT dosage on treatment outcomes. The Benjamini–Hochberg procedure was used to adjust P values and maintain the false discovery rate at 5%. Among 636 patients, 296 (46.5%) achieved functional recovery (38.5% in the ten-session group, 46.5% in the 20-session group, and 52.9% in the ≥ 30-session group). After adjustment for baseline fusion status, stereoacuity, and convergence amplitudes, each additional ten VT sessions was associated with a 5% increase in the odds of functional recovery (odds ratio, OR = 1.05, 95% CI 1.02 – 1.07; P = 0.003). Patients with better baseline Worth Dot fusion at 3 m were more likely to meet recovery criteria (OR = 1.28 per 1-point increase, 95% CI 1.12 – 1.48; P < 0.001). Moreover, worse baseline stereoacuity at near (OR = 0.43 per 1-log10 arcsec increase, 95% CI 0.30–0.62; P < 0.001) and far (OR = 0.12 per 1-log10 arcsec increase, 95% CI 0.06–0.23; P < 0.001) were associated with a reduced likelihood of functional recovery. Age, gender, treatment frequency, baseline Worth Dot at 33 cm or 1 m, and baseline convergence amplitudes were not associated with outcomes. Significant improvements were observed for nearly all measured clinical parameters. Office-based VT was associated with functional recovery in patients with IXT, with greater gains in those who received more therapy sessions and had better baseline binocular function. Prospective, randomized trials are needed to confirm these findings.