ABSTRACT
To characterize the role of the marginal or Z myotomy of the inferior oblique muscle, we review a series of patients with small angle hypertropia and inferior oblique overaction having undergone this procedure. Ten patients had inferior oblique Z myotomies performed alone or in conjunction with horizontal strabismus surgery. Our results yielded an average reduction in primary gaze hypertropia of 2.45 – 6.35 PD. The percent reduction of deviation in the three eye positions most effected was consistently 70 – 80%. As evidenced by the standard deviations, many patients had 100% correction of their deviation leaving them Orthophoric. There were no overcorrections. Previous overaction of the inferior oblique, measured by duction testing, was improved in all patients. We propose the Z myotomy as another tool in the strabismologist’s armamentarium for small angle hypertropia with inferior oblique overaction to predictably decrease the deviation to fusional range or prismatic spectacle fusional range with low risk of overcorrection.
