The Relationship between Binocular Function and the Surgical Outcome of Intermittent Exotropia

ABSTRACT

PURPOSE: This study was designed to determine the relationship between binocular function and the surgical outcome of intermittent exotropia. METHODS: The surgical outcome and binocular function were retrospectively investigated in 44 patients who had undergone surgery for intermittent exotropia with at least 6 months of post-operative follow-up. We evaluated visual acuity, age at operation, angle of exodeviation, fusional status with Worth-4-dot test and stereoacuity with Titmus test before and after surgery. RESULTS: A 'surgical success' defined as a final alignment of orthophoria, esotropia less than 5PD or exotropia less than 10PD at far primary position, was achieved in 31 patients (70%). The surgical outcome according to preoperative stereopsis and fusional status was not statistically significant. Whereas, there was a tendency toward more surgical success in patients with central fusion and the first postoperative day diplopia but statistically indifferent. There was an improvement of stereoacuity in 34 out of 44 patients after surgery. The fusional status was improved in 9 patients out of 44 patients. There was an improvement of postoperative binocular function regardless the surgical outcome. But the achievement of fine stereopsis below 100 seconds of arc and central fusion increased only in success group. CONCLUSIONS: The preoperative binocular function did not contribute significantly to the surgical outcome (p>0.05) and postoperative binocular function could be improved by surgical correction in both surgical success and failure group. But the better binocular function was achieved by successful surgical alignment.