Zu Haicheng, Zhang Kunya, Zhang Haixia, Qian Xiuqing
School of Biomedical Engineering, Capital Medical University, Beijing 100069, China.
Beijing Key Laboratory of Fundamental Research on Biomechanics in Clinical Application, Capital Medical University, Beijing 100069, China.
Bioengineering (Basel). 2023 May 26;10(6):646. doi: 10.3390/bioengineering10060646.
The vitreous body keeps the lens and retina in place and protects these tissues from physical insults. Existing studies have reported that the mechanical properties of vitreous body varied after liquefaction, suggesting mechanical properties could be effective parameters to identify vitreous liquefaction process. Thus, in this work, we aimed to propose a method to determine the mechanical properties of vitreous bodies. Fresh porcine eyes were divided into three groups, including the untreated group, the 24 h liquefaction group and the 48 h liquefaction group, which was injected collagenase and then kept for 24 h or 48 h. The indentation tests were carried out on the vitreous body in its natural location while the posterior segment of the eye was fixed in the container. A finite element model of a specimen undertaking indentation was constructed to simulate the indentation test with surface tension of vitreous body considered. Using the inverse method, the mechanical parameters of the vitreous body and the surface tension coefficient were determined. For the same parameter, values were highest in the untreated group, followed by the 24 h liquefaction group and the lowest in the 48 h liquefaction group. For C in the neo-Hookean model, the significant differences were found between the untreated group and liquefaction groups. This work quantified vitreous body mechanical properties successfully using inverse method, which provides a new method for identifying vitreous liquefactions related studies.
玻璃体将晶状体和视网膜固定在原位，并保护这些组织免受物理损伤。现有研究报道，玻璃体液化后其力学性能会发生变化，这表明力学性能可能是识别玻璃体液化过程的有效参数。因此，在本研究中，我们旨在提出一种确定玻璃体力学性能的方法。将新鲜猪眼分为三组，包括未处理组、24小时液化组和48小时液化组，对后两组注射胶原酶并分别保存24小时或48小时。在眼后段固定于容器中的情况下，对玻璃体在其自然位置进行压痕试验。构建了一个进行压痕试验的标本有限元模型，以模拟考虑玻璃体表面张力的压痕试验。采用逆方法确定了玻璃体的力学参数和表面张力系数。对于相同参数，未处理组的值最高，其次是24小时液化组，48小时液化组的值最低。对于新胡克模型中的C，未处理组与液化组之间存在显著差异。本研究成功地采用逆方法量化了玻璃体的力学性能，为玻璃体液化相关研究提供了一种新方法。
