Long-term Surgical Results of Children with Intermittent Exotropia

Objective: To investigate the long-term clinical effects and postoperative changes in children with intermittent exotropia. Methods: In this retrospective case series study, 139 children with intermittent exotropia and who underwent strabismus surgery were followed for more than 12 months. Distant and near squint angles as well as binocular visual function parameters were collected preoperatively, at 1 week and 1 month postoperatively, and at the last follow-up. Independent sample t-tests were used to compare the distant and near squint angles between the pre- and postoperative periods. Chi-square tests were used to analyze distant and near sensory fusion and stereopsis. Results: The mean age was 7.4 ± 2.6 years (range 4-14 years), and the follow-up time was 21.0 ± 10.5 months (range 12-51 months). The preoperative distant and near deviation were -33.9△ ± 10.9△(range -20△- -75△) and -38.2△ ± 10.2△(range -20△- -85△), respectively. At the final follow-up examination, the mean postoperative distant and near squint angles were -6.4△ ± 8.0△(+16△- -35△) and -7.7△ ± 9.6△(+ 20△- -40△) respectively. Among the patients, 103 cases (74.1%) were orthophoric, 35 cases (25.2%) had recurrent exotropia, and 1 case (0.7%) showed overcorrected strabismus. Bilateral visual acuity was significantly improved at the final follow-up examination. The distant and near perceptual fusion were significantly improved ( χ2=26.88, 26.24, P < 0.001), as was the distant and near stereopsis ( χ2=64.38, P < 0.001; χ2=14.63, P=0.002). The 35 patients who relapsed at the last follow up had significantly improved perceptual fusion function ( χ2=14.58, P=0.002) and better distant and near stereopsis acuity, although the changes were not statistically significant. Conclusions: Approximately 75% of the children with intermittent exotropia maintained long-term orthophoria after surgery, and their binocular vision was significantly improved. Even in children with postoperative recurrence, binocular visual function was better than before surgery. Key words: intermittent exotropia; recurrence; binocular vision; long-term effect