Argento Alan, Kim Wonsuk, Rozsa Frank W, DeBolt Kori L, Zikanova Sophia, Richards Julia R
J Biomech Eng. 2014 Jul;136(7). doi: 10.1115/1.4027615.
Ocular tissue properties have been widely studied in tension and compression for humans and a variety of animals. However, direct shear testing of the tissues of the sclera appear to be absent from the literature even though modeling, analyses, and anatomical studies have indicated that shear may play a role in the etiology of primary open angle glaucoma (POAG). In this work, the mechanical behavior of bovine scleral tissue in shear has been studied in both out-of-plane and in-plane modes of deformation. Stress-strain and relaxation tests were conducted on tissue specimens at controlled temperature and hydration focusing on trends related to specimen location and orientation. There was generally found to be no significant effect of specimen orientation and angular location in the globe on shear stiffness in both modes. The in-plane response, which is the primary load carrying mode, was found to be substantially stiffer than the out-of-plane mode. Also, within the in-plane studies, tissue further from the optic nerve was stiffer than the near tissue. The viscosity coefficient of the tissue varied insignificantly with distance from the optic nerve, but overall was much higher in-plane than out-of-plane.
眼部组织特性已在人类和多种动物的拉伸与压缩方面得到广泛研究。然而，尽管建模、分析和解剖学研究表明剪切力可能在原发性开角型青光眼（POAG）的病因中起作用，但巩膜组织的直接剪切测试在文献中似乎并不存在。在这项工作中，研究了牛巩膜组织在平面外和平面内变形模式下的剪切力学行为。在控制温度和水合作用的条件下，对组织样本进行了应力 - 应变和松弛测试，重点关注与样本位置和方向相关的趋势。通常发现，在两种模式下，样本方向和在眼球中的角度位置对剪切刚度均无显著影响。作为主要承载模式的平面内响应被发现比平面外模式要硬得多。此外，在平面内研究中，离视神经较远的组织比靠近视神经的组织更硬。组织的粘性系数随与视神经距离的变化不显著，但总体而言，平面内的粘性系数比平面外高得多。
