Causes and Outcomes of Treatment for Superior Oblique Palsy during a Decade at Labbafinejad Medical Center

Purpose: Superior oblique palsy is a common cause of paralytic strabismus. This disorder causes diplopia, head posture and facial asymmetry. This retrospective study reviews patient with superior oblique (SO) palsy operated at Labbafinejad Medical Center from 1997 to 2007. Methods: In this descriptive study, records of patients with SO palsy scheduled for surgery were reviewed. Forced duction test (FDT) and tendon laxity was checked in each patient. Patients were divided into congenital and acquired subgroups. Results: During the study period, 83 patients were referred for surgery. Of these 73 patients with complete records (45 males, 28 females) were enrolled into our study, with age ranging from 1.5 to 62 (mean 19.7 ±11.7) years. SO palsy was congenital in 56 patients (76%) and acquired in 17 patients (24%). Most patients (47.9%) had left side and 13.7% had both eyes involvement. The most common chief complaint was ocular deviation (52.1%). The following abnormalities were noted: positive FDT 7 patients (9.7%), tendon laxity 2 patients (2.7%), amblyopia 14 patients (19.2%), facial asymmetry 5 patients (6.8%), head tilt 10 patients (13.7%), and chin down position 3 patients (4.1%). Mean preoperative vertical deviation was 16.2 ±8.3 which was reduced to 1.9 ±4 prism diopters after surgical intervention (P<0.05). Mean exotropia and esotropia were 15 ±9.5 and 13.9 ±11.5 prism diopters before operation, respectively and both were reduced to mean horizontal deviation of 1.5 ±4.8 prism diopters after operation (P<0.05). The most common Knapp classification of disease was type 3 (42.5%). The most common muscle operated was the inferior oblique (83.6%) and the most common type of operation was the inferior oblique myectomy. Conclusion: The most common form of superior oblique palsy leading to operation is the congenital form which occurs most commonly in young men. The most popular surgical intervention at this center was inferior oblique myectomy.