Comparison of horizontal muscle transposition and Inferior oblique weakening combined with horizontal surgery in V-pattern exotropia

Abstract

Purpose The objective of this study was to compare the effects of horizontal muscle transposition and inferior oblique weakening combined with horizontal surgery performed for V-pattern exotropia (XT) and to determine the most successful approach. Methods In our retrospective study, 52 patients who underwent horizontal surgery due to V-pattern XT and were followed up for at least 6 months were divided into two groups. Group 1 (n = 26) consisted of patients who underwent vertical transposition of the rectus muscles combined with horizontal surgery, and group 2 (n = 26) consisted of patients who underwent inferior oblique weakening combined with horizontal surgery. The two groups were compared before and after surgery in terms of visual acuity, refractive errors, deviation angles, pattern strabismus, fusion, stereopsis, over/under correction and surgical success. Results There was no difference between the two groups in terms of age, follow-up period, visual acuity, refractive errors, fusion or stereopsis. The amount of horizontal deviation was smaller in group 2 at the 1-6-month follow-ups. There was no difference between the two groups in terms of pattern collapse; however, the amount of pattern postoperatively was lower in group 2. The two groups were similar in terms of overcorrection; however, the undercorrection rate was higher in group 1. The surgical success rate was higher in group 2. Conclusions Inferior oblique weakening combined with horizontal surgery due to V-pattern XT was found to be superior to vertical transposition of the horizontal muscles in terms of surgical success and the amount of pattern postoperatively.