The Role of Stereopsis and Binocular Fusion in Surgical Treatment of Intermittent Exotropia

Abstract

Background/Aims: The purpose of this study is to identify the appropriate timing for surgical treatment of intermittent exotropia (XT) in the pediatric population by examining several parameters that may contribute to surgical planning. Methods: A retrospective chart review was conducted on patients between the ages of 3 and 17 years undergoing surgical management for intermittent XT. Preoperative and postoperative data regarding age, past medical history, visual acuity, stereopsis, magnitude of deviation and control was recorded. Medical records were reviewed and analyzed to determine if preoperative control of near misalignment, stereopsis, or presence of amblyopia may play a role in surgical outcome. Results: Ninety-five patients met inclusion criteria. Mean age was 6.71 years. Mean follow up period was 10.79 months. At least 140 sec arc of stereopsis using Titmus testing was present in 39.5% of patients preoperatively, while 55.8% of patients had less than 140 sec arc preoperatively, indicative of poor fusion at near. 47.2% of patients had good control of the near misalignment preoperatively, while 52.7% of patients had fair to poor control preoperatively. There was no statistically significant difference in surgical outcomes when comparing preoperative level of control of misalignment at near (P=0.2284) and stereopsis (P=0.2537). Presence of amblyopia preoperatively also had no association with surgical outcome (P=1.00). Conclusion: The use of worsening stereopsis and/or alignment control at near as parameters to determine the appropriate time for surgical intervention does not predict improved outcomes in patients with intermittent XT.