The advancement of the medial rectus muscle for consecutive exotropia.
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.


METHODS
Retrospective cohort study.


METHODS
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.
Strabismus Center of Ophthalmology, Korea University College of Medicine, Seoul, Republic of Korea.
Yoonae A
YA
Cho
Won Yeol
WY
Ryu
D002648:Child; D002675:Child, Preschool; D003867:Depth Perception / Q000502:physiology; D004948:Esotropia / Q000503:physiopathology / Q000601:surgery*; D005099:Exotropia / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009801:Oculomotor Muscles / Q000503:physiopathology / Q000601:surgery*; D013508:Ophthalmologic Surgical Procedures; D012189:Retrospective Studies; D016896:Treatment Outcome; D015348:Vision, Binocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology