J Korean Ophthalmol Soc > Volume 60(3); 2019 > Article
Journal of the Korean Ophthalmological Society 2019;60(3):268-275.
DOI: https://doi.org/10.3341/jkos.2019.60.3.268    Published online March 15, 2019.
Comparison of the Outcomes of Two- and Three-muscle Surgery in Exotropia over 45 Prism Diopters.
Kyung Eun Kang, Hyung Chan Kim, Hyun Jin Shin
Department of Ophthalmology, Konkuk University School of Medicine, Seoul, Korea. shineye@kuh.ac.kr
45 프리즘디옵터 이상의 편위각을 지닌 외사시에서 두 근육과 세 근육 수술법의 비교
건국대학교 의학전문대학원 안과학교실
Correspondence:  Hyun Jin Shin,
Email: shineye@kuh.ac.kr
Received: 5 July 2018   • Revised: 15 October 2018   • Accepted: 20 February 2019
We report the outcomes of two- or three-muscle surgery on patients with large-angle exotropia exceeding 45 prism diopters (PDs). METHODS: We retrospectively analyzed data on 45 exotropia patients (> 45 PDs) who underwent two- or three-muscle surgery. We excluded patients with paralytic or restrictive strabismus, A- or V-pattern strabismus, a coexistent oblique dysfunction or nystagmus, and/or a history of prior extraocular muscle surgery. Only patients for whom at least 6 months of follow-up data were available were included. Successful surgery was defined as postoperative esotropia ≤ 5 PD, orthophoria, and exotropia ≤ 10 PD at the last visit. RESULTS: We included 45 patients, of whom 22 and 23 underwent two- and three-muscle surgery, respectively. The mean postoperative deviations were 9.5 and 2.7 PD in the two- and three-muscle groups, respectively; the overall success rates were 54.55% (12/22) and 91.30% (21/23). Subgroup analyses revealed that the surgical success rate of two-muscle operations was 66.67% (12/18) in 45–55 PD patients and 0% (0/4) in ≥ 55 PD patients; the success rates of three-muscle operations were 100% (7/7) and 87.50% (14/16). The success rate did not differ significantly between those with postoperative deviations of 45–55 PD (p = 0.137), but did between those who underwent two- and three-muscle operations to treat postoperative deviations of ≥ 55 PD (p = 0.003). CONCLUSIONS: Satisfactory results can be achieved via two-muscle surgery in patients with exotropia < 55 PD. However, for those with exotropia > 55 PD, three-muscle surgery is superior to two-muscle surgery. Therefore, large-angle exotropia is optimally treated via three-muscle surgery.
Key Words: Horizontal muscle surgery;Large angle exotropia;Strabismus muscle

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