Inferior Oblique Muscle Overaction: Clinical Features and Surgical Management

Abstract

Purpose. To further define the clinical features of patients with inferior oblique muscle overaction (IOOA) and evaluate the surgical results in a subgroup of these patients. Methods. The medical records of 173 patients who underwent inferior oblique muscle (IO) weakening surgery due to primary or secondary IOOA were retrospectively reviewed. The patients were assigned a surgical group based on severity of IOOA and presence of dissociated vertical deviation (DVD) or hypertropia. Patients with +1 or +2 IOOA underwent recession, patients with +3 or +4 IOOA underwent myectomy, and patients with any grade of IOOA and DVD or hypertropia underwent anterior transposition (AT) surgery. Results. A total of 286 eyes of 173 patients who underwent surgery due to IOOA were included in the study. IOOA was accompanied by esotropia, exotropia, abnormal head posture (AHP), pattern strabismus, convergence insufficiency, DVD, facial asymmetry, and nystagmus. The most common comorbid disorder was esotropia. The recession was used in 173 eyes, myectomy in 64, and AT in 49. Surgical success was obtained in 96.0% of eyes that underwent recession, in 98.4% of eyes that underwent myectomy, and in 93.9% of eyes that underwent AT. In the follow-up, IOOA occurred in the fellow eye in 36.1% of patients who underwent unilateral surgery. Conclusions. This study is a comprehensive report on the concomitants of the IOOA. Also, it showed that all of the three surgical procedures including recession, myectomy, and AT are effective in the surgical management of IOOA when performed in select patient groups.

Effect of bilateral inferior oblique partial myectomy on V pattern exotropia with inferior oblique overaction

“…They concluded that no significant difference was found between the two groups; however, bilateral surgery had a higher rate of causing IO undercorrection. E M Helveston reported that contralateral IOOA was aggravated postoperatively with unilateral IO weakening [ 9 ]. Manal Kasem et al reported that 66.6% of patients with unilateral IOOA developed contralateral IOOA in the myectomy group ( P < 0.001) [ 22 ].…”

“…Costenbader FD et al analyzed three different IO weakening procedures and suggested that the effects of myotomy at its origin, recession at the scleral insertion and partial myectomy were similar [ 8 ]. Ercan Ozsoy et al studied the efficacy of IO weakening treatment in 179 patients with IOOA and showed that the cure rates of IO recession, myectomy and anterior transposition were 96%, 98.4% and 93.9%, respectively [ 9 ]. Antielevation syndrome was found in patients with IOOA who underwent IO anterior transposition.…”

“…They concluded that IOOA was significantly improved after symmetrical surgery without dysfunctional IO. However, currently reported data examining the effectiveness and safety of symmetric IO partial myectomy for V-pattern exotropia with bilateral IOOA are limited [ 9 – 13 ]. In addition, the efficacy of symmetric IO partial myectomy has not been assessed quantitatively using methodologically sound research.…”

Novel Inferior Oblique Muscle Y Splitting Procedure to Minimize the Anti-Elevation Syndrome: A Pilot Study

“…Nevertheless, these procedures are also intended to correct the primary gaze hypertropia as well as excyclotorsion. [1][2][3][4][5][6][7] In clinics, the inferior oblique muscle overaction is frequently encountered in infantile esotropes, where it can be witnessed in up to 70% of the cases, 1 such overactions can also be witnessed in superior oblique palsy, comitant horizontal deviations, dissociated vertical deviation, and others. To treat it, in milder grades (usually 1+), we prefer 8-10 millimeters of inferior oblique recession, and in grade 2+ we prefer 12-14 millimeters of recessions or Elliott and Nankins procedure.…”

“…All these techniques are able to cure the over-elevation in adduction, and also they are able to collapse the associated "V" pattern strabismus, 1,5,7 however, the anteriorization procedures are quite famous for their anti-elevation effect, or the antielevation syndrome (as described by Kushner). 9,10 Where, due to anatomical changes in the inferior oblique muscle course and its associated neurovascular bundle the vertical rotation is limited, clinically, it can be witnessed as elevation deficit in abduction as well as in primary gazes (Figure 1).…”