The effect of inferior oblique muscle weakening on horizontal alignment

Abstract

PurposeTo determine the postoperative horizontal alignment changes following different inferior oblique (IO) weakening procedures on cases with IO overaction (IOOA).MethodsA total of 40 patients undergoing IO weakening surgery participated in this prospective interventional case series. A comprehensive ophthalmic examination was performed on all patients. The grade of IOOA was assessed based on the muscle function in the gaze of elevation in adduction. All study subjects were operated on by one of the IO weakening procedures including recession, myectomy, or anteriorization, and all were followed up for at least three months after the surgery. Postoperative change of the horizontal alignment in primary position was the main outcome measure.ResultsOur findings showed that all types of IO weakening surgeries improved the postoperative muscle function, hypertopia, and V-pattern significantly (P = 0.001). Generally, IO weakening surgeries had no effect on the postoperative horizontal alignment, and mean exoshift of 0.44 ± 6.2 prism diopters (PD) was observed in all study subjects, specifically. It was found that 70% of cases had no postoperative horizontal changes, 15% showed improvement toward orthophoria, and 15% shifted away from orthophoria.ConclusionsBased on our findings, no horizontal alignment change would be expected in the majority of cases undergoing weakening procedures of overacted IO. Most of our cases did not show any change while a few of them presented eso- or exoshift less than 5 pd which can be clinically ignored.

Development and Validation of a Nomogram for Predicting Second Surgery in Patients with Concomitant Esotropia

“…In addition to the six risk predictors screened in this study, there were many other potential risk factors for CE surgery. Many authors [ 19 – 21 ] have discussed potential factors, such as the distance-near disparity of deviation angles, whether it was accompanied by signs such as IOOA and DVD, whether vertical strabismus was performed at the same time, the time of wearing glasses before surgery, the duration of strabismus, the surgical method, anisometropia, and insufficient vergence function. However, the results of these factors are quite different in different studies.…”