Medial rectus resection(s) with adjustable suture for intermittent exotropia of the convergence insufficiency type

Background: The surgical results for intermittent exotropia of the convergence insufficiency type have been reported to be of varying success. The purpose of this study is to evaluate the surgical results of medial rectus muscle (MR) resection(s) with adjustable suture for this condition. Methods:Twenty-one consecutive patients with intermittent exotropia of the convergence insufficiency type were included in this retrospective study. All patients had a history of prolonged difficulties at near work unrelieved by nonsurgical treatment. Unilateral or bilateral MR resection(s) were done with the adjustable suture, which was tied at the first postoperative day. The target angle was an esotropia of 10 to 20 PD at distance and an esotropia of 5 to 10 PD at near. Postoperatively Fresnel prisms were used temporarily in patients manifesting a consecutive esotropia with diplopia at distance. Postoperative follow-up period was between 6 months and 24 months with a mean of 9.1 months. Results: MR resection(s) with the adjustable suture reduced the mean exodeviation at near from 25.7 to 3 PD. It also reduced the exodeviation at distance from 11.4 to -2 PD (esodeviation). The mean near-distance difference was collapsed from 14.3 PD preoperatively to 5 PD postoperatively. Conclusions: MR resection(s) with adjustable suture combined with intentional postoperative aggressive overcorrection and the use of Fresnel prisms is useful in intermittent exotropia of the convergence insufficiency type. The intentional overcorrection during the immediate postoperative period at distance and near is required to prevent long-term undercorrection.