The advancement of the medial rectus muscle for consecutive exotropia

• Published in: Canadian journal of ophthalmology 2013-08, Vol.48 (4), p.300-306
• Main Authors: Cho, Yoonae A., MD, PhD, Ryu, Won Yeol, MD
• Format: Article
• Language: English
• Subjects: Child; Child, Preschool; Depth Perception - physiology; Esotropia - physiopathology; Esotropia - surgery; Exotropia - etiology; Exotropia - physiopathology; Exotropia - surgery; Female; Humans; Infant; Internal Medicine; Male; Oculomotor Muscles - physiopathology; Oculomotor Muscles - surgery; Ophthalmologic Surgical Procedures; Ophthalmology; Retrospective Studies; Treatment Outcome; Vision, Binocular - physiology; Visual Acuity - physiology
• ISSN: 0008-4182; 1715-3360
• DOI: 10.1016/j.jcjo.2013.03.003

Abstract Objective To characterize the dose effect of the advancement of the medial rectus muscle (MR) for consecutive exotropia (XT) after corrective surgery for infantile esotropia (ET) and provide a guide for achieving orthotropia. Design Retrospective cohort study. Participants Seventy-seven patients with consecutive XT that developed after surgery for infantile ET. Methods All patients underwent advancement of the unilateral or bilateral MR and were followed up for at least 1 year. The angle of deviation and stereopsis were retrospectively reviewed from patient records. Results At the time of surgery for infantile ET, the mean eso-angle was 52.2 ± 13.10 prism diopters (PD; mean age, 28.5 ± 16.97 months). The exo-angle of consecutive XT was 25.6 ± 8.47 PD (mean age at surgery, 132.7 ± 82.32 months). The mean deviation was 1.8 ± 10.40 PD XT at the final follow-up (47.0 ± 43.57 months). The corrective effect of the exo-angle for a 1-mm advancement of the MR was 3.1 PD at 1 year after surgery and 2.9 PD at the last follow-up. There was a significant positive relationship between the preoperative exo-angle and the corrective effect of the 1-mm advancement of the MR at the last follow-up ( r = 0.367, p < 0.05). Postoperatively, orthotropia was present in 79.2% of patients, re-exodrift in 16.9%, and ET in 3.9%. Favourable stereopsis was achieved in 73.2%. Conclusions MR advancement was effective for treating consecutive XT, followed by recession of the MR for infantile ET, achieving favourable stereopsis. The corrective value was 3 PD per 1-mm advancement of the MR.