Bimedial hang-back recession -- outcomes and surgical response

AIM: To report outcomes and identify factors affecting surgical response for constant esotropia using 'hang-back' bimedial rectus recession. STUDY TYPE: Retrospective case series analysis. METHODS: Patients managed by a single surgeon over a 4-year study period were categorized into esotropia types: infantile, partially accommodative, nonaccommodative and secondary esotropia. Postoperative alignment was compared between types, and regression modelling used to examine factors predicting surgical response. RESULTS: In all, 95% (18/19) of children with partially accommodative esotropia achieved postoperative deviation <15 prism dioptres from orthotropia, compared to 56% (15/27) of children with infantile esotropia, 69% (11/16) of children with non-accommodative esotropia and all (2/2) of those with secondary esotropia. Surgical response (Delta/mm recession performed) increased with the magnitude of both preoperative deviation (P<0.001) and anisometropia (P<0.001); the effect of deviation on surgical response was reduced by amblyopia (P=0.02). Age at surgery was statistically associated (P=0.002) but had negligible clinical effect on response. CONCLUSIONS: Surgical response to hang-back recession may be partially predicted by preoperative factors.