Surgical dose–responses of bilateral medial rectus muscle recession in acute acquired comitant esotropia compared to infantile esotropia

Objective: To determine the surgical dose–responses of the bilateral medial rectus recession in acute acquired comitant esotropia (AACE) compared to infantile esotropia. Design: Retrospective study. Methods: The medical records of patients diagnosed with AACE and infantile esotropia who underwent bilateral medial rectus muscle recession (BMRR) were reviewed. Patient characteristics, ocular examinations and surgical data were collected. A motor success was defined as horizontal deviation within 10 prism diopters (PD) of ortho, and a sensory success was defined as no diplopia at 6 months after the surgery. Results: A total of 114 patients were included. There were 39 patients with AACE [median (Q1–Q3) age was 20 (15–25) years, 56% was female] and 75 patients with infantile esotropia [median (Q1–Q3) age was 3 (1–5) years, 56% was female]. The surgical dose–responses of BMRR in AACE at distance and near were 2.67 PD/mm (r2 = 22.8%) and 3.48 PD/mm (r2 = 32.9%), respectively. The surgical dose-responses of BMRR in infantile esotropia at distance and near were 3.91 PD/mm (r2 = 17.8%) and 4.64 PD/mm (r2 = 18.0%), respectively. Seventy-four percent of patients with AACE and 63% of patients with infantile esotropia achieved a motor success. Eighty-five percent of patients with AACE achieved a sensory success. The postoperative drift at distance and at near was not significant in both groups [AACE 0 PD (−6 to 10), p = .26 and 2 PD (−2 to 6), p = .44; infantile esotropia [8 PD (0–14), p = .12 and 4 PD (0–10), p = .22]. Conclusions: The BMRR in infantile esotropia had a larger surgical dose–response than in AACE. In both groups, the surgical dose–responses at near were greater than at distance. There was no significant postoperative drift at distance and at near in both groups.