[Surgical treatment of A-pattern strabismus with over-acting superior oblique muscles].

13 cases of A-pattern strabismus with overacting superior oblique muscles were treated with Berke's procedure. Depending on the severity of superior oblique muscle overaction, simple tenotomy or partial tenectomy of the superior obliques was performed. For cases of A-pattern strabismus < 30 prism diopters, bilateral superior oblique muscle weakening might result in overcorrection, and for cases > 40 prism diopters, bilateral superior oblique weakening should be accompanied with vertical displacement of the horizontal muscles. For patients with stereoacuity of 40 arc seconds, surgery should be refrained from in order to avoid post-operative cyclodeviation.