Department of Ophthalmology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama City, Okayama, Japan.
Department of Orthoptics, Faculty of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki City, Okayama, Japan.
PLoS One. 2020 Dec 23;15(12):e0243382. doi: 10.1371/journal.pone.0243382. eCollection 2020.
This study aimed to evaluate the shape of the extraocular muscles (EOMs) in normal subjects using the en-face images of anterior segment optical coherence tomography (AS-OCT). The EOM insertion and the direction of the muscle fibers were investigated.
A total of 97 healthy normal subjects (194 eyes) at Okayama University Hospital (age, 47.1±21.5 years; range, 8-79 years) participated in the study. A series of 256 tomographic images of the rectus EOMs were captured using the C-scan function of the AS-OCT (CASIA2, TOMEY Co., Japan), and the images were converted to en-face images in multi-TIFF format. The anterior chamber angle to EOM insertion distance (AID) and the angle of the muscle fibers from the insertion site (angle of muscles) were measured from the images. The correlations of AID and angle of muscles with age and axial length were investigated and evaluated.
AID and angle of muscles were significantly correlated with age or axial length in some EOMs. The AIDs of medial rectus (MR) (P = 0.000) and superior rectus (SR) (P = 0.005) shortened with age. The AIDs of MR (P = 0.001) and inferior rectus (IR) (P = 0.035) elongated with axial length, whereas lateral rectus (LR) (P = 0.013) shortened. The angles of MR (P = 0.001) and LR (P = 0.000) were found to have a more downward direction toward the posterior in older subjects.
En-face images can be created by AS-OCT, and the shape of the EOMs in normal subjects using these image measurements was available. With the ability to assess the EOMs, AID and angle of muscles are expected give useful information for treating and diagnosing strabismus-related diseases.
本研究旨在使用眼前节光学相干断层扫描（AS-OCT）的矢状面图像评估正常受试者的眼外肌（EOM）的形状。研究了 EOM 的插入部位和肌纤维的方向。
共有 97 名来自冈山大学医院的健康正常受试者（194 只眼）参与了这项研究（年龄，47.1±21.5 岁；范围，8-79 岁）。使用 AS-OCT（TOMEY 公司的 CASIA2）的 C 扫描功能拍摄一系列 256 张直肌 EOM 的断层图像，并将图像转换为多 TIFF 格式的矢状面图像。从图像中测量前房角到 EOM 插入距离（AID）和插入部位的肌纤维角度（肌肉角度）。研究并评估了 AID 和肌肉角度与年龄和眼轴长度的相关性。
在某些 EOM 中，AID 和肌肉角度与年龄或眼轴长度显著相关。内直肌（MR）（P=0.000）和上直肌（SR）（P=0.005）的 AID 随年龄缩短。MR（P=0.001）和下直肌（IR）（P=0.035）的 AID 随眼轴长度延长，而外直肌（LR）（P=0.013）缩短。MR（P=0.001）和 LR（P=0.000）的肌肉角度在年龄较大的受试者中发现更向下朝向后方的方向。
AS-OCT 可创建矢状面图像，并且可使用这些图像测量来评估正常受试者的 EOM 形状。通过评估 EOM，AID 和肌肉角度有望为治疗和诊断斜视相关疾病提供有用的信息。
