人眼睫状体在调节中形态与位置的动态变化

目的了解健康活体人眼在自发视远视近调节中，睫状体形态和位置动态变化的特点。方法利用超声生物显微镜(UBM)的50MHz高频换能器，对68例正常人眼注视远、近不同视标时睫状体形态、位置的变化进行动态观测和统计学分析。结果(1)视近调节时，睫状体前部厚度、睫状突长度、睫状体总面积和环形肌面积增大，睫状突宽度及内尖成角、睫状突与小梁、虹膜、巩膜突的距离，以及其和虹膜、巩膜的夹角减小，前房角开放程度变小。而睫状体后部厚度、纵行肌面积、巩膜虹膜夹角以及小梁虹膜夹角的差异无显著意义。(2)形态各参数间的变化相辅相成、高度一致，位置各参数亦然，但形态与位置之间关系无显著意义。结论人眼视近调节时，睫状体各部肌纤维协调收缩，尤其是环形肌收缩，使睫状突变得尖而细长，睫状体向前向内移动，松弛悬韧带，支持Helmholtz的调节松弛学说。UBM可实时观测人眼调节时睫状体各部分形态和位置等的变化情况。

Dynamic changes of configuration and position of human ciliary body during accommodation

OBJECTIVE: To study the changes of the configuration and position of ciliary body of normal human eyes in spontaneous far and near accommodations. METHODS: The configuration and position in ciliary body of 68 normal human eyes were observed real-timely and measured by high frequency transducer of ultrasound biomicroscopy (UBM), when these eyes focused on given far and near optotypes, respectively. All of these parameters between far and near accommodations were compared by One-Way Analysis of Variance (One-Way ANOVA) and Multivariate ANOVA of General Linear Model (MANOVA of GLM), and were correlated with each other respectively (alpha=0.05). RESULTS: (1) In near accommodation, there were statistically significant increase in the thickness of anterior ciliary body, length of ciliary process, whole area of ciliary body and area of circular fibers. There were statistically significant decreases in width of ciliary process, angle of inner apex, distances between ciliary process and trabecula, iris, scleral spur, and angles between ciliary process and iris, ciliary process and sclera; there was also a certain decrease in angle-opening distance 500 microm from the scleral spur. There were no significant changes in the thickness of posterior ciliary body; area of meridional fibers; angle between sclera and iris and angle between trabecula and iris. (2) Parameters of configuration had close correlation with each other, and it was also true in those of position. But, the correlation between the configuration and position was not significant. CONCLUSIONS: In the process of near accommodation, ciliary body shifts forwards and inwards, ciliary process becomes tapered because the harmonious contraction of its circular and meridional muscle fibers. This is consistent with the classical relaxation mechanism of accommodation described by Helmholtz. UBM is a new noninvasive method for real-time studying of the ciliary body changes in far-near accommodating human eyes in vivo.