虹膜组织力学特性实验方法的探索

A research on experiment method of iris biomechanical properties

目的虹膜膨隆程度与虹膜的生物力学特性有关,本研究根据生物力学原理创造了压力载荷实验方法探索瞳孔阻滞力。方法 1.试样与实验装置:实验平台包括卡具、压力加载与记录系统、计算机图像处理系统等;2.实验方法与过程:取兔眼去角膜,水密缝合瞳孔,保留虹膜与巩膜的完整连接,后巩膜剪开,除净玻璃体、晶状体,完成试样。将试样固定于卡具上并与压力加载系统及记录系统相连通,在恒温水浴下进行压力载荷实验。3.数据处理与计算:用首都医科大学生物力学研究中心开发的软件测量、计算面积应变量ε_s、面积模量E_s。结果共20只兔30眼完成了3次完整的加载卸载实验。所拍图像经测量计算得到ε_s、E_s数值,结合压强P数据可绘得ε_s—P曲线,E_s—P曲线。结论用压力载荷实验方法代替传统的拉伸实验方法是可靠可行的。压力载荷实验方法是生物力学研究方法的一个创新。

Purpose The study on biomechanical properties of the iris is important for study of pupillary block. A new measuring method and instruments based on biomechanics principle are developed to study on rabbits iris. Methods The compressive stress load tests were performed on isolated living rabbit irises to determine the passive the mechanical behavior of the iris. The experimental device includes: the fixture, the compressive stress load and record device, dynamic testing system and the computer image manipulation system. The experiment courseis: to enucleate rabbit integrity eye ball and cut off the cornea, next to waterproof suture the iris along pupillary margin, and cut the post-sclera to clean the vitreous and lens, and then the specimen was fixed on fixture and connected with the compressive stress load and record device. The load and unload experiments were performed while the specimen was in 37℃ homeothermia water bath. Colorful CCD screened the iris pictures changes in-phase dynamically, and at the same time, pictures were inputted and stored into computer. All data were measured and calculated by software that was programmed by the Biomechanics Department of Capital University of Medical Sciences.Results Total thirty eyes from twenty rabbits were done with load and unload experiment for three times. The iris area strained with εs(εs=s-s0/s0) and the iris area strained with modulus E2 ( Es = P/εs) were calcularted . The graph of the area strained with—— compressive stress and the area strained with modulus——compressive stress have been gotten. Conclusion The compressive stress load tests can replace the routine tension experiments in this research. The new measuring method can be manipulated and it brings new ideas on biomechanical experimental method.