Regional variation in the biomechanical properties of the human sclera
Regional variation in the biomechanical properties of the human sclera
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DOI：
10.1016/j.exer.2010.02.010
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发表时间：
2010-05-01
影响因子：
3.4
通讯作者：
Rama, Paolo
中科院分区：
文献类型：
--
作者：
Elsheikh, Ahmed;Geraghty, Brendan;Rama, Paolo
该研究旨在确定人类巩膜不同区域之间的厚度和生物力学特性的变化。对36例52-96岁的供者巩膜进行了沿着8条子午线从后极到利姆布斯的厚度测量。从靠近利姆布斯、赤道和后极的区域提取条带样本，并在单轴拉伸循环下进行测试。两个应变率被认为是评估材料行为的区域变化的粘弹性效应。结果用于推导每个样本的应力应变行为，并计算每个应力水平下的切线模量。巩膜的厚度从后极的最大值到赤道附近的最小值不等，并向利姆布斯再次增加。所有巩膜标本表现出非线性行为，初始低切线模量（刚度的措施）逐渐增加，在较高的应力。关于特定应力水平，区域之间的行为比较显示材料切线刚度随着从后部区域向利姆布斯的进展而逐渐增长。组织的粘弹性，这是明显的应力（157-203%）和切线模量（30.3-38.8%）与应变率上升（从8%到200%每分钟）的显着增加，与刚度的区域变化的减少。在这项研究中发现的生物力学行为的相当大的变化应该是有用的，在提高代表巩膜的数值模拟的真实生活条件的准确性。(C)2010爱思唯尔有限公司版权所有。
The study aimed to determine the variation in thickness and biomechanical properties between the different regions of the human sclera. Thickness measurements were carried out along eight meridian lines extending from the posterior pole to limbus in 36 human donor scleras aged 52-96 years. Strip specimens were extracted from areas close to the limbus, equator and posterior pole, and tested under cycles of uniaxial tension. Two strain rates were considered to assess the viscoelasticity effects on the regional variation in material behaviour. The results were used to derive the stress strain behaviour of each specimen and to calculate the tangent modulus at each stress level. The scleras had a variable thickness from maximum at the posterior pole to minimum close to the equator, and increasing again towards the limbus. All scleral specimens demonstrated nonlinear behaviour with an initially low tangent modulus (a measure of stiffness) increasing gradually under higher stresses. With reference to specific stress levels, the behaviour comparisons between regions showed a gradual growth in material tangent stiffness with progression from the posterior region towards the limbus. The viscoelasticity of the tissue, which was evident with significant increases in stress (157-203%) and tangent modulus (30.3-38.8%) with strain rate rise (from 8% to 200% per min), was associated with reductions in the regional variation in stiffness. The considerable variation in biomechanical behaviour found in this study should be useful in improving the accuracy of representing the sclera's real-life conditions in numerical simulations. (C) 2010 Elsevier Ltd. All rights reserved.