Outcome of extraocular muscle transpositions in various types of strabismus

Background: Transposition surgery of extraocular muscles helps in paralytic strabismus by altering the direction of force in relation to the center of rotation of the eye. Hence, the study was done to report the outcome of muscle transpositions. Materials and Methods: This was a prospective interventional study of 20 patients conducted at our tertiary ophthalmic institute over a period of 2 years and included ten patients with “V” pattern and four patients with “A” pattern strabismus, two patients with monocular elevation deficiency (MED), two patients with third nerve palsy, and one patient each with Duane’s retraction syndrome (DRS) and Crouzon’s syndrome. Fourteen patients underwent correction of horizontal strabismus with vertical transposition of horizontal recti, four patients underwent upward transposition of lateral rectus (LR) muscle, one patient underwent modified Knapp’s procedure, and one patient had “Y” split of LR muscle with transposition. Results: Ten patients with “V” pattern strabismus and four patients with “A” pattern strabismus had satisfactory collapse of pattern postoperatively with <10 prism diopters (PD) and 15 PD of mean residual horizontal strabismus, respectively. Both patients with MED had good improvement in primary position alignment. Upshoot in DRS patient was corrected. Two out of six patients who had preoperative limitation of duction had improvement postoperatively. Conclusion: Extraocular muscle transposition resulted in alignment of eyes, collapse of alphabet pattern, and improvement in ocular motility in these patients. Proper patient selection and planning of the suitable type of transposition surgery helps in achieving the desired outcome.