A Valid Indication and the Effect of Bilateral Inferior Oblique Transposition on Recurrent or Consecutive Horizontal Deviation in Infantile Strabismus

Abstract

Purpose: To evaluate the effects of bilateral inferior oblique transposition (BIOT) on horizontal deviation fromprimary position among patients with bilateral dissociated vertical deviation (DVD) associated with inferioroblique overaction (IOOA) in infantile strabismus. Methods: Retrospective chart review was conducted among 19 patients with infantile strabismus. All patientshad DVD and IOOA with consecutive or recurrent horizontal deviation and underwent modified BIOT surgery. Patients were divided into three subgroups: patients who underwent BIOT (BIOT group, n = 9) alone, BIOTwith medial rectus recession or lateral rectus resection simultaneously (ET BIOT group, n = 6), or BIOT withlateral rectus recession or medial rectus resection simultaneously (XT BIOT group, n = 4). Postoperative angleof horizontal deviation (prism diopter, PD) and corrected magnitude of horizontal deviation (PD) at final visit aftersurgery were analyzed in each group. Results: The mean age was 55.11 ± 21.05 months (range, 32 to 115). The mean follow-up period was 8.68 ± 2.87months (range, 6 to 18). Preoperative horizontal deviation was 4.23 ± 5.99 PD (range, 0 to 16) in BIOT, –17.33 ±6.76 PD (range, –30 to –10) in ET BIOT, and 17.50 ± 2.52 PD (range, 14 to 20) in XT BIOT. Esodeviation is representedby negative values. DVD and IOOA were reduced less than +1 in all patients. The corrected amountof horizontal deviation was 3.56 ± 5.18 PD (range, 0 to 16) in BIOT surgery alone and larger in XT BIOT (18.50± 3.41 PD) than in ET BIOT (12.33 ± 5.57 PD, p = 0.004). Conclusions: Minimal exodeviation was corrected by BIOT alone. In addition, secondary eso- or exodeviationat great magnitudes should be corrected with proper horizontal muscle surgery along with BIOT.