Characteristics and Outcome in Horizontal Strabismus Combined with Unilateral Superior Oblique Palsy

ABSTRACT

PURPOSE: To review the clinical characteristics and treatment outcomes in horizontal strabismus combined with unilateral superior oblique palsy (SOP). METHODS: A retrospective review of medical records was conducted in 21 patients with unilateral SOP treated between January 2001 and December 2005. Patients had more than 6 months of follow-up at the Department of Ophthalmology, Wonju College of Medicine. RESULTS: Among 21 patients (11 male, 10 female) with unilateral SOP, 57.1% of patients had horizontal strabismus. The mean vertical deviation was 12.56+/-3.81 (8~24) PD. All patients with horizontal strabismus had exotropia and the mean deviation was 10.57+/-4.58 (6~20) PD. A standard 10mm inferior oblique (IO) recession was performed uniformly at the paretic eye in all patients. In 7 of the patients (58.3%, exotropia greater than or equal to 10PD), horizontal rectus muscle recession was performed simultaneously. In these 7 cases, vertical and horizontal deviation less than or equal to 4PD was achieved (one patient with 10PD remaining hypertropia excluded). In 5 cases with exodeviation less than 10PD, isolated IO recession without horizontal rectus recession on the ipsilateral side achieved orthophoria in the primary position. In 9 cases of isolated SOP, all patients showed orthophoria in the primary position. CONCLUSIONS: This study demonstrates horizontal strabismus is combined with unilateral SOP in a high percentage of patients. Additionally, in all cases, all the incidents of horizontal deviation was involved exotropia. A standard 10 mm recession of the IO in combination with horizontal rectus recession is an effective surgical technique. It has an especially high success rate in patients with unilateral SOP (< or =14PD vertical deviation) with exodeviation greater than 10PD. In patients with exodeviation less than 10PD, an isolated IO recession is sufficiently effective.