Risk Factors for Consecutive Exotropia and Hyperopic Changes after Bilateral Medial Rectus Recession

Abstract

Purpose: To define risk factors for and to analyze changes in hyperopic refractive error during development of postoperative exotropia (XT) after bilateral medial rectus (BMR) recession to treat infantile esotropia. Methods: We retrospectively examined 50 patients with infantile esotropia who underwent BMR recession from January 2005 to December 2010. All were < 10 years of age and underwent >= 36 months of follow-up. We recorded age at operation, the preoperative strabismus angle, the extent of medial rectus recession, strabismus status, pre-and post-operative changes in the refractive errors of both eyes, any postoperative overcorrection, any dissociated vertical deviation (DVD), and inferior oblique overaction (IOOA) status. Results: Consecutive XT developed in 18 (36%) patients. The preoperative refractive error was + 0.90 +/- 0.79 D in the consecutive XT group and + 1.94 +/- 1.48 D in the surgical success (SS) group (p = 0.019). The extent of hyperopic decrease was significantly greater in the consecutive XT group than the SS group (consecutive XT group: 1.59 +/- 1.38 D, SS group: 2.86 +/- 1.97 D) at 3 years of post-operative follow-up (p = 0.008). Postoperative IOOA was detected in 10 (70.5%) patients in the consecutive XT group and 3 (29.55%) in the SS group (p = 0.002). No significant between-group difference in the incidence of overcorrection or DVD was apparent. Conclusions: The presence of hyperopia (>+ 2.0 D) prior to BMR recession and a marked fall in the extent of hyperopia (-1.0 D/year) after recession may be associated with a high risk of consecutive XT. Thorough follow-up is necessary when IOOA develops after BMR recession.