Effect of Inferior Oblique Myectomy with Anterior Transposition on Inferior Oblique Over-action and DVD

To compare the efficacy of inferior oblique myectomy and anterior transposition for correcting Inferior Oblique Over Action (IOOA) and DVD.
This retrospective study was carried out on patients with IOOA who had either myectomy or an­terior transposition of the inferior oblique muscle from 2010 to 2015. The authors compared pre-operative and post-operative inferior oblique muscle function grading (-4 to ) as the main outcome measure; vertical and horizontal deviation, dissociated vertical deviation (DVD), and A V-pattern between the two surgical groups as secondary outcomes.
A total of 99 eyes of 56 patients with a mean age of 5.9 ± 6.5 years were included (47 eyes in the myectomy group and 52 eyes in the anterior transposition group). There were no differences in pre-operative best corrected visual acuity, amblyopia, spherical equiva­lent, and primary versus secondary IOOA between the two groups. Both surgical procedures were effective in reducing IOOA and satisfactory results were similar be­tween the two groups: 61.7% and 67.3% in the myec­tomy and anterior transposition groups, respectively (P= 0.56). After adjustment for the pre-operative DVD, there was no statistically significant difference between the two groups post-operatively. The pre-operative hypertro­pia was 6 to 14 and 6 to 18 prism diopters (PD) in the myectomy and anterior transposition groups, respec­tively. After surgery, no patient had a vertical deviation greater than 5 PD.
Both the inferior oblique myectomy and anterior transposition procedures are effective in reducing IOOA with similar satisfactory results. DVD and hypertropia were also corrected similarly by these two surgical procedures.