Strabismus Surgery in Orthophoric Patients with Abduction Limitation.

Background: Patients with symptomatic esotropia in lateral gaze after lateral rectus recession may not be offered surgery if they are orthophoric in primary gaze due to concern of creating diplopia in primary gaze. There are currently no reports of the surgical management of these cases. The purpose of this study was to report our experience and describe the surgical outcomes for these rare patients. Methods: A comprehensive, retrospective review of all patients undergoing strabismus surgery at Boston Children's Hospital over an 11-year period identified all cases of orthophoric patients operated on for diplopia in lateral gaze following lateral rectus recession(s). Surgical approach, pre- and post-operative measurements in diagnostic gaze positions, and surgical outcomes were assessed. We developed a new lateral incomitance (LI) score to characterize patient disability before and after surgery. Main outcome measures were improvement in LI score and lateral gaze diplopia, lack of new-onset diplopia in primary gaze, and patient/surgeon satisfaction. Results: In all cases, previously recessed lateral rectus muscles were advanced 2-3 mm with an adjustable suture technique despite anticipated exotropia in primary gaze. Early, large-angle, transient sequential exotropia with diplopia was common. All patients had resolution of lateral-gaze diplopia with improvement in LI score by 8-18 PD, and none experienced persistent new-onset diplopia in primary gaze (median follow-up 16 months; range, 8.5-83 months). One patient with a history of surgery for convergence insufficiency developed a well-controlled intermittent exotropia; no other patient had exotropia in primary gaze. Conclusion: Small, adjustable advancements of the lateral rectus muscles provided excellent results in our series of patients with lateral gaze esotropia caused by previous lateral rectus recessions. Despite large, early overcorrections, LI scores improved in all cases, and no patient had recurrence of symptomatic exotropia. The results will support surgical decision-making in the management of these challenging cases.