Efficacy of Transposition of Plicated Medial Rectus Muscles in the Treatment of Pattern Exotropia (A Comparative Study)

PURPOSE To report effectiveness of bimedial plication and vertical transposition for the correction of exotropia associated with A- or V-pattern and compare it with bimedial resection and vertical transposition. METHODS We retrospectively reviewed the results of surgery of patients who underwent bimedial plication (group I) versus bimedial resection (group II) with vertical offset to correct both exotropia and pattern deviation not secondary to oblique overaction in the period between January 2021 and January 2023. Results of both groups were compared. Success was considered when pattern deviation was ≤ 8 prism diopters PD and horizontal deviation was within 10 PD of orthophoria at 6 months postoperatively. RESULTS The mean preoperative angle of exotropia in PD was 40.6 +/- 7.2 in group I and 41.1 +/- 7.5 in group II (p=.8). At 6 months postoperatively, they achieved esotropia of 4.6 +/- 4.1 and 2.5 +/- 4.5 PD respectively (no significant difference between both groups; p=.19). The mean preoperative pattern deviation was 21.3 +/- 3.7 PD in group I and 21.6 +/- 4.4 in group II. Postoperative pattern collapse was 16.7 +/- 5.6 and 16.6 +/- 4.1 respectively. The percentage of success in pattern collapse was 90.6% in group I and 84.4% in group II (no significant difference between both groups; p=.71). CONCLUSION Vertical transposition with plication of the medial recti is a safe, effective, and rapid technique for the correction of cases of A- or V- pattern exotropia not associated with oblique overaction. Surgical results were comparable to resection and vertical transposition.