Motor and sensory outcomes after botulinum toxin A injection versus unilateral medial rectus recession in small-to-moderate angle esotropia.

Abstract

Purpose: To compare the motor and sensory outcomes of botulinum toxin A (BTA) injection and unilateral medial rectus recession (MRR) in patients with small-moderate angle esotropia.

Methods: This retrospective cohort study included patients with 10-25 prism diopter (PD) esotropia, including non-accommodative, partially accommodative, residual, and infantile subtypes, who underwent either BTA injection or unilateral MRR. Preoperative and postoperative ocular alignment was evaluated at 1, 3, 6, and 12 months. Motor success was defined as postoperative deviation within 0-10 PD. Sensory outcomes were assessed based on stereopsis and worth 4 dot test changes. Non-parametric tests (Mann - Whitney U, Wilcoxon signed-rank) were used for continuous variables, and Chi-square or Fisher's exact tests for categorical variables.

Results: A total of 38 patients were included (18 BTA, 20 MRR). The surgical group demonstrated significantly better early alignment at 1 month (p < .001). However, the differences in motor alignment between the groups gradually decreased, and by the 3rd, 6th, and 12th months their alignment values had become similar (p = .577, p = .067, and p = .083, respectively). Undercorrection was more frequent in the BTA group (33.3% vs. 5.0%, p = .038), and five patients required a repeat injection. Sensory outcomes (stability/improvement/deterioration) showed no significant differences between groups (p > .05 for all). No major complications occurred in either group.

Conclusion: Both BTA injection and unilateral MRR provide satisfactory motor alignment in moderate-angle esotropia, although early postoperative outcomes favor surgery. The long-term similarity of motor outcomes and comparable sensory results suggest that BTA may serve as a minimally invasive, repeatable alternative particularly in younger patients or those with small-to-moderate deviations.