This study evaluated the surgical results for constant and intermittent exotropia to investigate the factors that might influence the surgical results in a Scandinavian population. This was a retrospective study from 2011-2015 during which time 633 patients had strabismus surgery for exotropia. The authors excluded 342 patients because of coexistent vertical deviation, incomplete records and prior surgery. They reported results for 291 patients. The main indication for surgery was asthenopia (n=131), psychosocial reasons (n=82), diplopia (n=41), loss of stereopsis (n=6), increased angle (n=5) and abnormal head posture in two. No reason was recorded for 24 patients. Objective surgery success was obtained for 223 at six-week follow-up (76.6%). Surgical success was 80% for intermittent and 70% for constant exotropia. Long-term follow-up after one year was reported for 17.5% of patients (15 constant, 36 intermittent). There was no significant change for constant exotropia but significant drift for intermittent exotropia at near and distance angles. Reoperation rate was 4.4% with no difference for constant or intermittent cases. Factors affecting surgical success were considered with the highest success rate found for those with smallest preoperative distance angles. Overall, surgical success was equally good for constant and intermittent exotropia although the authors noted long-term drift in intermittent exotropia. Small deviations had better results. The authors also proposed that distance / near incomitance should be considered in deciding the extent of medial and lateral rectus muscle surgery.
