Bilateral inferior oblique myectomy for asymmetric primary inferior oblique overaction

To evaluate the effects of bilateral symmetric inferior oblique myectomy on the symmetry of versions of patients with bilateral asymmetric primary inferior oblique overaction.

A prospective interventional study was performed on 32 consecutive patients with bilateral asymmetric inferior oblique overaction. All patients were treated with bilateral symmetric inferior oblique myectomy. The versions, degree of inferior oblique overaction, and degree of fundus torsion were analyzed in all patients before and after surgery. Patients were included in the study only if they achieved a minimum follow-up of 6 months.

There was marked improvement in the degree of the inferior oblique overaction in all patients. Eighty-one percent of the patients had no residual inferior oblique overaction on either side by the end of the 6-month follow-up period. None of the patients developed clinically significant inferior oblique underaction. Consequently, there was marked improvement in the comitance of the versions. None of the patients developed significant A or V pattern after surgery.

In the presence of asymmetric inferior oblique overaction, bilateral symmetric inferior oblique myectomy may have a "symmetrizing" effect on the inferior oblique overaction and greatly improve the comitance of the versions.