The use of one muscle recession for horizontal strabismus

Purpose: To evaluate the outcomes of one muscle recession for horizontal comitant strabismus at a major referral hospital in the Middle East. Method: Retrospective charts review of postoperative outcomes of 90 patients who had undergone one muscle recession for small to moderate angle esotropia or exotropia. Data were collected for age, vision, amblyopia, previous surgery or botulinum toxin injection, preoperative deviation, amount and type of one muscle surgery, and postoperative deviation at the initial and last (six months or more) postoperative visit. Successful alignment was defined as +/- 10 prism diopters (PD) of orthophoria. Results: Sixty patients underwent medial rectus recession and 30 patients underwent lateral rectus recession. The average preoperative and last follow up deviation -respectively- was 24 +/- 6.1 PD (15-35) PD and 14.62 +/- 8.91 PD in the medial rectus recession group and 21.3 +/- 5.1 PD (12-30) and 12.60 +/- 8.74 in the lateral rectus recession group. The final success rates were 63.3% in both groups. Conclusion: Single muscle strabismus surgery to correct horizontal strabismus had a variable outcome. Larger recession may help in achieving better outcomes. Properly designed prospective studies may help in identifying the factors affecting the outcomes of single muscle strabismus surgeries.