An improved spinning lens test to determine the stiffness of the human lens.
An improved spinning lens test to determine the stiffness of the human lens.
复制标题
改进的旋转透镜测试以确定人透镜的刚度。
DOI：
10.1016/j.exer.2010.10.010
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发表时间：
2011-01
影响因子：
3.4
通讯作者：
Judge, S. J.
中科院分区：
文献类型：
--
作者：
Burd, H. J.;Wilde, G. S.;Judge, S. J.
人们普遍认为，与年龄相关的透镜硬度变化对老视的发展具有重要意义。然而，年龄相关的透镜硬度变化的相对重要性的精确细节，与其他潜在的老视发展机制相比，尚未建立。造成这种不确定性的一个因素是关于透镜刚度的实验数据的缺乏和可变性。现有的公开数据通常表明，透镜内的刚度在空间上变化，并且刚度参数倾向于随着年龄而增加。然而，这些公布的数据集在质量和数量上都存在相当大的差异。本文介绍了新的和改进的方法，旋转透镜的方法的基础上，开创性的费舍尔，R. F。（1971）“The elastic constants of the human lens”，Journal of Physiology，212，147-180，以测量人类透镜的刚度。这些新的程序已经被开发，试图消除，或至少大大减少，各种系统误差在费舍尔的原始实验。一个改进的试验台已经建成，并确定透镜的刚度参数，在测试过程中所作的观察，设计了一个新的建模程序。该实验涉及将人类透镜安装在垂直转子上，使得透镜在其光轴上旋转（通常以1000 rpm）。自动成像系统用于在透镜以预定的角度取向旋转时捕获该透镜的轮廓。这些图像用于量化由于旋转引起的向心力而在透镜中产生的变形。透镜刚度推断使用轴对称有限元逆分析，其中一个几乎不可压缩的neo-Hookean本构模型被用来表示的透镜的力学。数值优化程序是用来确定刚度参数，提供一个最佳的有限元模型和实验数据之间的配合。提供了年龄为33岁的人类透镜的样本结果。设计了一种新的旋转透镜装置来测量人体透镜的刚度。开发了有限元分析程序，以根据测试结果确定透镜刚度数据。该实验能够研究透镜中的空间刚度变化。
It is widely accepted that age-related changes in lens stiffness are significant for the development of presbyopia. However, precise details on the relative importance of age-related changes in the stiffness of the lens, in comparison with other potential mechanisms for the development of presbyopia, have not yet been established. One contributing factor to this uncertainty is the paucity and variability of experimental data on lens stiffness. The available published data generally indicate that stiffness varies spatially within the lens and that stiffness parameters tend to increase with age. However, considerable differences exist between these published data sets, both qualitatively and quantitatively. The current paper describes new and improved methods, based on the spinning lens approach pioneered by Fisher, R.F. (1971) ‘The elastic constants of the human lens’, Journal of Physiology, 212, 147–180, to make measurements on the stiffness of the human lens. These new procedures have been developed in an attempt to eliminate, or at least substantially reduce, various systematic errors in Fisher’s original experiment. An improved test rig has been constructed and a new modelling procedure for determining lens stiffness parameters from observations made during the test has been devised. The experiment involves mounting a human lens on a vertical rotor so that the lens spins on its optical axis (typically at 1000 rpm). An automatic imaging system is used to capture the outline of the lens, while it is rotating, at pre-determined angular orientations. These images are used to quantify the deformations developed in the lens as a consequence of the centripetal forces induced by the rotation. Lens stiffness is inferred using axisymmetric finite element inverse analysis in which a nearly-incompressible neo-Hookean constitutive model is used to represent the mechanics of the lens. A numerical optimisation procedure is used to determine the stiffness parameters that provide a best fit between the finite element model and the experimental data. Sample results are presented for a human lens of age 33 years. ► A new spinning lens rig has been devised to measure the stiffness of the human lens. ► Finite element analysis procedures are developed to determine lens stiffness data from the test results. ► The experiment is capable of investigating spatial stiffness variations in the lens.
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影响因子：
3.4
作者：
Augusteyn, Robert C.
通讯作者：
Augusteyn, Robert C.
影响因子：
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通讯作者：
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作者：
Schumacher, Silvia;Oberheide, Uwe;Lubatschowski, Holger
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作者：
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