Surgical Result of Intermittent Exotropia According to Angle of Deviation at Lateral Gaze

ABSTRACT

PURPOSE: This study investigated the surgical result of intermittent exotropia according to the difference between primary gaze and lateral gaze, where the extent of surgical treatment was decided by the angle of deviation in primary gaze. METHODS: The subjects of this study were 128 patients who had intermittent exotropia and were operated on by the same surgeon. Deviation angle of strabismus was checked at near and distance and primary and 30-degree lateral directions of gaze. The Worth 4 dot test and Titmus test were performed. Refixation time and axial length were measured. Either the cycloplegic refraction test or manifest refraction test was done depending on the patient's age. The extent of surgery was decided by the criteria recommended by Parks. Patients were classified into 2 groups. Group 1 included patients with 5-PD or smaller differences in the angle of deviation in the primary and lateral gaze. Patients who had differences greater than 5-PD in the angle of deviation according to the direction of gaze were classified as group 2. Clinical data were verified by Pearson Chi-square test. RESULTS: Age, sex, angle of deviation at near and distance, oblique muscle function, spherical equivalent, astigmatism, axial length, stereopsis, and refixation time did not affect the difference in the angle of deviation according to the direction of gaze. The non-fusion group showed a large difference in the angle of deviation according to the direction of gaze. The extent of surgery was determined by the deviation angle in primary gaze. Both group showed similar surgical results. CONCLUSIONS: To determine the degree of surgery needed, it is reasonable to measure the deviation angle in primary gaze for patients with intermittent exotropia.