The Optimal Surgical Strategy and Dose for Esotropia

The study objective was to determine the clinical predictors of surgical failures following horizontal strabismus surgery for esotropia, in order to estimate the model-predicted optimal surgical strategy. A retrospective pooled observational case series of published cases was performed. Patients having horizontal strabismus surgery for esotropia, published between 1940 and 2025, with known preoperative deviation, surgical approach, and outcome were studied. Clinical data from individual patients having strabismus surgery for esotropia were recorded from published case series and analyzed using multivariable logistic regression to predict over- and under-correction. The main outcome measure was surgical failure, as determined by reoperation, suture adjustment, or postoperative strabismus of 10 prism diopters (PD) or more. We abstracted individual patient data for 3518 surgeries from 163 publications. Binocular (as compared with monocular) surgery was associated with fewer under-corrections (odds ratio (OR): 0.75, 95% confidence interval (CI): 0.61 to 0.92, p=0.005) and more over-corrections (OR: 1.87, 95% CI: 1.26 to 2.79, p=0.002, n=3266). Increasing preoperative deviation was associated with more under-corrections (OR: 1.06/°, 95% CI: 1.05/° to 1.07/°, p<0.0001) and fewer over-corrections (OR: 0.97/°, 95% CI: 0.95/° to 0.99/°, p=0.001, n=3266). Increasing surgical dose was associated with fewer under-corrections (OR: 0.95/mm, 95% CI: 0.91/mm to 0.99/mm, p=0.01) and more over-corrections (OR: 1.08/mm, 95% CI: 1.01/mm to 1.16/mm, p=0.02, n=3266). The failure rate was minimized with a large per-muscle surgical dose. As the preoperative deviation increases, one progresses from unilateral recessions, to unilateral recession-resections, and then to bi-medial recessions. Under a range of assumptions, bi-medial recessions of 6 mm are optimal (according to the models) for preoperative deviations of 45-50 prism diopters. We conclude that larger doses for esotropia surgery do produce a larger response. Most models predicted the lowest failure rates with large recessions or resections, with additional muscles operated for larger preoperative deviations.