Oblique Muscle Overaction and Anisotropia in Infantile Esotropia with Abduction Nystagmus

Abstract

Frequent oblique muscle overaction in infantile esotropia and the development of such overaction after horizontal surgical alignment in patients with normal oblique function prior to surgery, led us to study this dysfunction in two hundred and eighty-one cases of infantile esotropia and ninety-eight of late onset esotropia. Inferior oblique overaction proved more frequent than superior oblique overaction in both groups. However, the incidence of inferior oblique overaction was not significantly different in infantile esotropia versus esotropia of late onset, while superior oblique overaction proved more frequent in infantile esotropia. Post-surgical development of oblique muscle overaction in infantile esotropia patients with normal preoperative oblique function reached 19.3%. In esotropia of late onset, the development of oblique muscle overaction after horizontal surgery was minimal and only observed in two cases.