The Clinical Characteristics of Superior Oblique Palsy Associated With Intermittent Exotropia

ABSTRACT

PURPOSE: The goal of this study was to determine the clinical characteristics of patients with intermittent exotropia (IXT) associated with hypertropia. METHODS: This study recruited 268 hospital patients with IXT associated with hypertropia. After taking history, measuring the angle of deviation, conducting an ocular motor examination, performing a Bielschowsky head tilt test and taking a fundus photograph, the clinical characteristics of 23 patients diagnosed with superior oblique palsy (SOP) were investigated. RESULTS: Twenty-three patients (8.6%) of the 268 subjects with IXT associated with hypertropia were diagnosed with SOP. The average angle of exodeviation was 17.1+/-3.8PD and the angle of hypertropia at primary position was 12.9+/-5.9PD. Excyclotorsion of an eyeball was observed in 19 patients (82.6%), the Bielschowsky head tilt test was positive in all patients, and head tilt or face turn was found in 12 (52.2%) patients. All subjects had inferior oblique overaction, and 20 (86.9%) had superior oblique underaction. Operations to weaken the inferior oblique muscle of the paralytic eye and for horizontal muscles were conducted at the same time. The angle of exodeviation and the angle of hypertropia were, on average, 1.8+/-3.6PD and 2.4+/-2.2PD, respectively, 6 months after the operation. CONCLUSIONS: When patients with intermittent exotropia have hypertropia, the possibility of SOP should be considered. SOP can be detected by determining a history of head tilt and conducting a Bielschowsky head tilt test. Surgical treatment for SOP is advised.