摘要
目的用MRI研究轴性高度近视眼直肌位置变化，探讨轴性高度近视继发性眼球运动障碍的病因。设计前瞻性比较性病例系列。研究对象17～48岁轴性高度近视12例（22眼），年龄匹配的正常对照者20例（40眼）。方法高度近视者分为眼轴27～29mm、无眼球转动受限者（A组）；眼轴〉29mm、眼球外转及上转受限者（B组）。动态MRI技术获取眼球原在位及上转、下转、内转、外转位时的冠状MRI图像，图像处理软件测量原在位时眼球一视神经连接平面上4条直肌横截面中心相对眼眶中心的坐标值。主要指标直肌横截面中心相对眼眶中心的坐标值。结果A组与正常对照组4条直肌的横截面中心相对眼眶中心的坐标值比较均无显著差异（P均〉0．05）；B组与正常对照组内直肌、上直肌、下直肌的横截面中心相对眼眶中心的坐标值比较无显著性差异（P均〉0．05），但外直肌的横截面中心相对眼眶中心的坐标值较正常对照组向颞下移位（P〈0．01）；A组与B组内直肌、上直肌、下直肌的位点比较无显著性差异（P〉0．05），B组较A组外直肌的位点向颞下移位（P〈0．05）。结论外直肌止端向颞下移位可能是引起轴性高度近视继发性眼球运动障碍的重要原因。
Objective To study the location of rectus muscle with dynamic magnetic resonance imaging （MRI） in axial high myopia and its mechanisms of dyskinetie ocular movement. Design Prospective comparative case series. Participants 12 cases （22 eyes） of axial high myopia patients aged from 17 to 48 and 20 cases （40 eyes） of normal subjects with similar age as control. Methods The patients were divided into two groups according to myopic degree. Group A had no dysfunction of eye movements with axial length of 27-29 ram; Group B had limitation in abduction and supraduction with axial length longer than 29 mm. Multiple contiguous quasi-coronal MRI images perpendicular to the orbital axis were acquired at primary gaze, supraduction, infraduction, abduction, and adduction by dynamic MRI. The area centroids of vertical rectus at secondary horizontal gaze and horizontal recti at secondary vertical gaze were then determined by image software. Rectus paths were defined as the connection of the area centroids and plotted in a nor- malized oeuloeentric coordinate system. Main Outcome Measures The change values of function point of rectus in orbit. Results In group A, all rectus muscle locations have no statistically significant change compared with those in control （P〉0.05）. In group B, the function point of medial, superior and inferior rectus pulley have no statistically significant change compared with those in control or with those in Group A（all P〉0.05）, while the lateral rectus muscle function points showed significant inferior and temporal displacement （P〈0.01）. Conclusions The inferior dislocation in temporal site of lateral rectus may be the main cause of dysfunction of eye movements in axial high myopia.
出处
《眼科》
CAS
2011年第4期279-282,共4页
Ophthalmology in China
关键词
高度近视眼
眼球运动
眼外肌
磁共振成像
high myopia
eye movements
extraocular museles
magnetic resonance imaging
