Ocular Biomechanics, Legacy Health System, Portland, Oregon, USA.
Invest Ophthalmol Vis Sci. 2010 Jan;51(1):295-307. doi: 10.1167/iovs.09-4016. Epub 2009 Aug 20.
To investigate the biomechanical response to IOP elevation of normal monkey eyes using eye-specific, three-dimensional (3-D) finite element (FE) models of the ONH that incorporate lamina cribrosa (LC) microarchitectural information.
A serial sectioning and episcopic imaging technique was used to reconstruct the ONH and peripapillary sclera of four pairs of eyes fixed at 10 mm Hg. FE models were generated with local LC material properties representing the connective tissue volume fraction (CTVF) and predominant LC beam orientation and used to simulate an increase in IOP from 10 to 45 mm Hg. An LC material stiffness constant was varied to assess its influence on biomechanical response.
Strains and stresses within contralateral eyes were remarkably similar in both magnitude and distribution. Strain correlated inversely, and nonlinearly, with CTVF (median, r (2) = 0.73), with tensile strains largest in the temporal region. Stress correlated linearly with CTVF (median r(2) = 0.63), with the central and superior regions bearing the highest stresses. Net average LC displacement was either posterior or anterior, depending on whether the laminar material properties were compliant or stiff.
The results show that contralateral eyes exhibit similar mechanical behavior and suggest that local mechanical stress and strain within the LC are correlate highly with local laminar CTVF. These simulations emphasize the importance of developing both high-resolution imaging of the LC microarchitecture and next-generation, deep-scanning OCT techniques to clarify the relationships between IOP-related LC displacement and CTVF-related stress and strain in the LC. Such imaging may predict sites of IOP-related damage in glaucoma.
利用特定于眼的、包含视盘筛板（LC）微观结构信息的三维（3-D）有限元（FE）模型，研究正常猴眼眼压升高的生物力学反应。
使用一系列切片和外照成像技术，对四对固定在 10mmHg 下的眼睛的视盘和视盘周围巩膜进行重建。生成的 FE 模型具有代表结缔组织体积分数（CTVF）和主要 LC 梁取向的局部 LC 材料特性，用于模拟眼压从 10mmHg 增加到 45mmHg。改变 LC 材料刚度常数以评估其对生物力学反应的影响。
对侧眼的应变和应力在幅度和分布上都非常相似。应变与 CTVF 呈负相关（中位数，r²=0.73），与非线性相关，在颞区拉伸应变最大。应力与 CTVF 呈线性相关（中位数 r²=0.63），中央和上区承受的应力最高。LC 的净平均位移是向后还是向前，取决于层状材料特性是顺应性的还是刚性的。
结果表明，对侧眼表现出相似的力学行为，并表明 LC 内的局部力学应力和应变与局部 LC CTVF 高度相关。这些模拟强调了开发 LC 微观结构的高分辨率成像和下一代深度扫描 OCT 技术的重要性，以阐明与 LC 相关的 LC 位移和与 CTVF 相关的 LC 内的应力和应变之间的关系。这种成像可能预测与眼压相关的 LC 损伤部位。
