Evaluation of Relationship Between Medial Rectus Muscle Features and Surgical Success in Infantile Esotropia

Purpose: To investigate the relationship of surgical success with medial rectus insertion distance and muscle width in patients with infantile esotropia who had undergone bilateral medial rectus recession. Material and Method: Sixty eyes of 30 patients who had undergone bilateral medial rectus (MR) recession surgery for infantile esotropia were included in the study. In all eyes, both the distance between the nasal aspect of corneoscleral limbus and anterior edge of MR insertion and the width of medial rectus at the insertion site were measured. The relationship of both these values and the differences in the 2 eyes with the surgical success was evaluated. Results: The mean age of the patients was 27.7 +/- 12.3 months (13-56 months), mean preoperative deviation was 46.17 +/- 10.88 PD, and the mean cycloplegic refraction was +1.16D. The mean distance of MR insertion was 5.09 +/- 0.48 mm and the width was 9.13 +/- 1.14 mm in all eyes. The insertion distances showed a difference of 0.5 mm between the right and left eyes in 40% of the patients. Bilateral medial rectus recession of 6 +/- 0.2 mm was done after measuring from the insertion site of the muscle. All the patients were followed for 18.57 +/- 6.5 months. Surgical success was achieved in 21 patients (70%), while 5 of the patients (16.7%) underwent a second surgery. There was no relation between surgical success and patients' gender, MR insertion distance or width. Also surgical success was independent from the difference of insertion distance and width between the two eyes of the patients. Discussion: There are many different studies supporting MR recession surgery either from MR insertion site or limbus in infantile esotropia. This study showed that it is safe and successful to perform MR recession by measuring from MR insertion site. Besides, the features of the muscles do not affect the postoperative results.