Detecting Mechanical Anisotropy of the Cornea Using Brillouin Microscopy.
Detecting Mechanical Anisotropy of the Cornea Using Brillouin Microscopy.
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使用布里渊显微镜检测角膜的机械各向异性。
DOI：
10.1167/tvst.9.7.26
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发表时间：
2020
影响因子：
3
通讯作者：
Scarcelli,Giuliano
中科院分区：
文献类型：
--
作者：
Webb,JoshuaN;Zhang,Hongyuan;SinhaRoy,Abhijit;Randleman,JamesBradley;Scarcelli,Giuliano
目的：利用布里渊显微镜检测角膜沿不同扰动方向的机械各向异性。方法：测量角膜整体(n=10)和角膜穿孔(n=10)与入射激光成不同角度的布里渊频移，从而探测沿不同方向的角膜纵向弹性模数。结果：我们检测到了角膜的机械各向异性，当仪器沿基质纤维方向从0探测到15和30的时候，平均频移分别增加了53 MHz和96 MHz。布里渊显微镜对水分含量高达96%的机械各向异性没有失去敏感性。我们通过实验测量和理论模拟了与水化无关的机械变化如何影响角膜交联性导致的频移，通过分离纯粹由于基质组织机械变化引起的交联术后大约100 MHz的频移增加。结论：即使在高度水化的角膜中，布里渊显微镜也对基质的机械各向异性敏感。模型和实验数据之间的一致性表明了布里渊频移、角膜水化状态和基质组织硬度之间的定量关系。翻译相关性：整个研究过程中验证的方案和模型为临床上全面测量角膜力学提供了一条途径；允许改进对交联术的长期机械效果的评估。
Purpose: The purpose of this study was to detect the mechanical anisotropy of the cornea using Brillouin microscopy along different perturbation directions.Methods: Brillouin frequency shift of both whole globes (n= 10) and cornea punches (n= 10) were measured at different angles to the incident laser, thereby probing corneal longitudinal modulus of elasticity along different directions. Frequency shift of virgin (n= 26) versus cross-linked corneas (n= 15) over a large range of hydration conditions were compared in order to differentiate the contributions to Brillouin shift due to hydration from those due to stromal tissue.Results: We detected mechanical anisotropy of corneas, with an average frequency shift increase of 53 MHz and 96 MHz when the instrument probed from 0 to 15 and 30 along the direction of the stromal fibers. Brillouin microscopy did not lose sensitivity to mechanical anisotropy up to 96% water content. We experimentally measured and theoretically modeled how mechanical changes independent of hydration affect frequency shift as a result of corneal cross-linking by isolating an approximately 100 MHz increase in frequency shift following a cross-linking procedure purely due to changes of stromal tissue mechanics.Conclusions: Brillouin microscopy is sensitive to mechanical anisotropy of the stroma even in highly hydrated corneas. The agreement between model and experimental data suggested a quantitative relationship between Brillouin frequency shift, hydration state of the cornea, and stromal tissue stiffness.Translational Relevance: The protocol and model validated throughout this study offer a path for comprehensive measurements of corneal mechanics within the clinic; allowing for improved evaluation of the long-term mechanical efficacy of cross-linking procedures.