Bao F, Jiang L, Wang X, Zhang D, Wang Q, Zeng Y
Affiliated Eye Hospital of Wenzhou Medical College, Wenzhou 325027, PR China.
J Med Eng Technol. 2012 Jan;36(1):17-21. doi: 10.3109/03091902.2011.629276. Epub 2011 Nov 15.
This study aims to obtain the biomechanical properties of porcine cornea so as to provide necessary biomechanical experimental basis for pig-to-human corneal xenotransplantation.
Seventeen fresh porcine corneal specimens obtained from pigs aged 4-6 months were examined under inflation conditions to determine the constitutive relationships of the material through dynamic loading conditions (pressure range: 1.47-42.66 mmHg). The forward deflection of porcine anterior corneal apex was measured by the laser displacement sensor. The pressure deformation results were analysed on the basis of shell theory to estimate Young's modulus of the cornea and derive its relationship with intraocular pressure (IOP).
The porcine corneas showed a nonlinear corneal forward displacement/IOP and stress/strain relationship with an initial low stiffness stage and a later high stiffness stage. In spite of the nonlinearity between the internal pressure and apex forward deflection, the relationship between the Young's modulus and the IOP was almost linear.
Compared with human corneas, porcine corneas exhibited a similar nonlinear behaviour but lower stiffness values. The biomechanical parameters of porcine cornea obtained from this test could be applied to numerical simulations of refractive surgery procedures and lay a foundation for pig-to-human corneal xenotransplantation.
本研究旨在获取猪角膜的生物力学特性，为猪角膜与人角膜异种移植提供必要的生物力学实验依据。
对17个取自4至6月龄猪的新鲜猪角膜标本进行充气条件下的检测，通过动态加载条件（压力范围：1.47 - 42.66 mmHg）确定材料的本构关系。用激光位移传感器测量猪角膜前顶点的前向位移。基于壳理论分析压力变形结果，以估算角膜的杨氏模量并推导其与眼内压（IOP）的关系。
猪角膜呈现出非线性的角膜前向位移/IOP以及应力/应变关系，具有初始低刚度阶段和随后的高刚度阶段。尽管内压与顶点前向位移之间存在非线性，但杨氏模量与IOP之间的关系几乎是线性的。
与人类角膜相比，猪角膜表现出类似的非线性行为，但刚度值较低。从该测试中获得的猪角膜生物力学参数可应用于屈光手术程序的数值模拟，并为猪角膜与人角膜异种移植奠定基础。
