PurposeWe wanted to examine the effect of graded recession and anteriorization of the inferior oblique muscle on patients suffering from unilateral superior oblique palsy.MethodsInferior oblique muscle graded recession and anteriorization were performed on twenty-two patients (22 eyes) with unilateral superior oblique palsy. The recession and anteriorization were matched to the degree of inferior oblique overaction and hypertropia. The inferior oblique muscle was attached 4 mm posterior to the temporal border of the inferior rectus muscle in six eyes, 3 mm posterior in five eyes, 2 mm posterior in five eyes, 1 mm posterior in five eyes, and parallel to the temporal border in one eye.ResultsThe average angle of vertical deviation prior to surgery was 11.3±3.9 prism diopters (PD). The total average correction in the angle of vertical deviation after surgery was 10.8±3.8 PD. In the parallel group, the average reduction was 14 PD. After surgery, normal inferior oblique muscle action was seen in eighteen of twenty-two eyes (81.8%).ConclusionsGraded recession and anteriorization of the inferior oblique muscle is thought to be an effective surgical method to treat unilateral superior oblique palsy of less than 15 PD.