What to Expect from Primary Inferior Oblique Overaction After Esotropia Surgery

Abstract

Abstract Background Overelevation in adduction is a common feature of patients with primary esotropia. This study evaluates the variation in ocular motility pattern in patients with primary inferior oblique (IO) muscle overaction after esotropia surgery.Methods The medical records of consecutive patients who underwent surgery for infantile, partially accommodative, and basic esotropia over eleven years and had at least one year of follow-up were reviewed. Patients with primary inferior oblique muscle overaction (IOOA) presented at baseline or during follow-up were selected and divided according to the first surgery performed concurrently with horizontal rectus surgery: without IO recession (NO-recess), with unilateral IO recession (UNIL-recess), and with bilateral IO recession (BIL-recess). The success and recurrence rates and the evolution of the non-operated IO muscles were evaluated.Results One hundred and ten patients were included – 53 NO-recess, 26 UNIL-recess, and 31 BIL-recess. Medial rectus muscle posterior fixation sutures surgery (PFS) was performed in 88.2% of patients for esotropia. A recession with graded anterior transposition was the weakening IO procedure. In the NO-recess group, 28 (52.8%) patients normalized their mild IOOA after PFS surgery alone. In the UNI-recess group, 16 (61.5%) patients showed worsening of the fellow eye IO muscle, which prompted additional surgery in 10 patients. In the BIL-recess group, all 31 patients (100%, 62 eyes) improved the adduction pattern of the operated eye. The surgical success rate was 88.5% in the UNIL-recess group and 80.6% in the BIL-recess group.Conclusion Graded anterior transposition of the inferior oblique muscle effectively normalizes versions. However, it’s frequent for a contralateral overaction to become manifest after unilateral IO surgery.