Pavlatos Elias, Perez Benjamin Cruz, Morris Hugh J, Chen Hong, Palko Joel R, Pan Xueliang, Weber Paul A, Hart Richard T, Liu Jun
J Biomech Eng. 2016 Feb;138(2):021015. doi: 10.1115/1.4032124.
Intraocular pressure (IOP) induced strains in the peripapillary sclera may play a role in glaucoma progression. Using inflation testing and ultrasound speckle tracking, the 3D strains in the peripapillary sclera were measured in nine human donor globes. Our results showed that the peripapillary sclera experienced through-thickness compression and meridional stretch during inflation, while minimal circumferential dilation was observed when IOP was increased from 10 to 19 mmHg. The maximum shear was primarily oriented in the through-thickness, meridional cross sections and had a magnitude slightly larger than the first principal strain. The tissue volume had minimal overall change, confirming near-incompressibility of the sclera. Substantial strain heterogeneity was present in the peripapillary region, with local high strain areas likely corresponding to structural heterogeneity caused by traversing blood vessels. These 3D strain characteristics provide new insights into the biomechanical responses of the peripapillary sclera during physiological increases of IOP. Future studies are needed to confirm these findings and investigate the role of these biomechanical characteristics in ocular diseases.
眼内压（IOP）在视乳头周围巩膜中引起的应变可能在青光眼进展中起作用。通过充气测试和超声散斑追踪，在9个供体眼球中测量了视乳头周围巩膜的三维应变。我们的结果表明，在充气过程中，视乳头周围巩膜经历了全层压缩和子午线拉伸，而当眼内压从10 mmHg升高到19 mmHg时，观察到最小的圆周扩张。最大剪切力主要沿全层、子午线横截面方向，其大小略大于第一主应变。组织体积总体变化最小，证实巩膜几乎不可压缩。视乳头周围区域存在显著的应变异质性，局部高应变区域可能与穿过血管引起的结构异质性相对应。这些三维应变特征为眼内压生理性升高期间视乳头周围巩膜的生物力学反应提供了新的见解。需要进一步的研究来证实这些发现，并研究这些生物力学特征在眼部疾病中的作用。
