Purpose: The purpose was to describe the medial rectus muscle elongation (MRE) procedure to treat very large-angle esotropia (ET) with surgery on a lower number of muscles.
Methods: Twenty patients with very large-angle ET (more than 70 PD) underwent the MRE procedure. In the MRE procedure, the muscle was split longitudinally into three parts. The wider central part was sutured with 6/0 vicryl and disinserted. The distal end of the peripheral parts (still attached to the original insertion), 7-9 mm away from the insertion, was sutured to the proximal end of the central part. At the end of the procedure, the distance of the anastomosis site from the insertion was named as the final elongation. The dose-response effect of the final elongation was calculated in bilateral MRE cases. The mean of the dose-response effect, obtained in the binocular surgery group, was used in the monocular surgery group to calculate the resection effect of lateral rectus (LR) muscle.
Results: Eleven patients underwent bilateral MRE and nine patients underwent unilateral MRE and LR muscle resection. The mean preoperative far and near deviation was 94.10 ± 19.33 PD. The mean postoperative deviation was 14.60 ± 18.07 PD for far and 14.50 ± 18.23 PD for near deviation. In bilateral MRE cases, the mean dose-response effect of the elongation was 5.53 ± 0.67 PD/mm for far and 5.58 ± 0.69 PD/mm for near deviation. The mean LR muscle resection effect was 6.41 ± 1.99 PD/mm for far and 6.28 ± 1.93 PD/mm for near deviation.
Conclusion: The MRE procedure seems an acceptable method to treat very large-angle ET with surgery on a lower number of muscles.