Changes in Types of Recurrent Intermittent Exotropia after Surgical Correction of Basic Type Intermittent Exotropia

Purpose: To report the surgical outcomes and changes in types of recurrent exotropia after surgical correction of basic type intermittent exotropia. Methods: We retrospectively analyzed the medical records of 91 patients who underwent reoperations for recurrent exotropia after primary surgical correction, and who visited our hospital for a period of at least one year after the reoperation. When distant deviation was >30 prism diopters (PD), we defined convergence insufficiency type (CI type) if the difference of the deviation angle was >10 PD and basic type exotropia if the difference was <10 PD. When distant deviation was <30 PD, we defined basic type exotropia if the difference of the deviation angle between at distant and near was <33% of the distant deviation angle, and CI type exotropia if the difference was >33% of the distant deviation angle. Results: The types of recurrent exotropia were similar to those of the preoperative condition in 68 patients (74.7%), and newly emergent CI type was observed in 23 patients (25.3%). With regard to the incidence of CI type, bilateral lateral rectus recession was more common than unilateral lateral rectus recession after primary surgery and medial rectus resection and unilateral lateral rectus recession, but the difference was not significant (p = 0.615). Recurrent CI type exotropia was observed 6 months after primary surgery (p < 0.001), but there was no significant difference in the timing of the reoperation between the two groups (p > 0.05). There was no significant difference in the success of reoperations between the two groups (p > 0.05). Conclusions: The types of recurrent exotropia after surgical correction of primary basic type intermittent exotropia differed from those of preoperative exotropia, which was not related to various factors before surgery. Recurrent exotropia was successfully treated by appropriately selected reoperations, regardless of the type of exotropia. J Korean Ophthalmol Soc 2018;59(8):760-765