Background: In cases of large-angle horizontal strabismus, standard two-horizontal muscle surgery is insufficient. Utilizing supramaximal recession and resection techniques would result in limited duction. True muscle transplantations have been explored in this scenario as a potential solution for this large angle deviation.
Objectives: to evaluate the long-term effects of muscle transplantation on patients with large-angle horizontal strabismus, assessing success rate, ocular alignment improvement, and patient satisfaction post-surgery.
Patients and methods: This prospective case series with 30 cases, divided into Group A (large-angle esotropia) and Group B (large-angle exotropia). The surgical procedure involved muscle transplantation using a recession technique. Preoperative evaluations, including comprehensive ophthalmic examinations, were conducted to determine the angle of deviation, visual acuity, and ocular motility. The participants underwent follow-up visits post-surgery.
Results: In Group A, the mean preoperative distance angle of deviation, measured in prism diopters (PD), was 80.67±11.63. The mean preoperative adduction and abduction restriction was -0.07±0.26, -0.73±0.96, respectively. The amount of lateral rectus (LR) resection, and medial rectus (MR) recession ranged from 6 to 9 mm, and 2 to 5 mm, respectively.
 In Group B, the mean preoperative distance angle of deviation, measured in prism diopters (PD), was 75.67±13.61. The mean preoperative adduction and abduction restriction was -1.47±1.36, - 0.53±0.74, respectively. The amount of medial rectus (MR) resection, and lateral rectus (LR) recession ranged from 6 to 8 mm, and 3 to 10 mm, respectively.
Conclusion: Muscle transplantation is an effective surgical technique for large angle horizontal strabismus. It leads to significant improvements in ocular alignment and movement restrictions.