Kirby Mitchell A, Regnault Gabriel, Pelivanov Ivan, O'Donnell Matthew, Wang Ruikang K, Shen Tueng T
Department of Bioengineering, University of Washington, Seattle, Washington 98105, USA.
Department of Ophthalmology, University of Washington, Seattle, Washington 98104, USA.
ArXiv. 2023 Jan 25:arXiv:2301.10652v1.
To demonstrate accurate measurement of corneal elastic moduli in vivo with non-contact and non-invasive optical coherence elastography.
Elastic properties (in-plane Young's modulus E and both in-plane, u, and out-of-plane, G, shear moduli) of rabbit cornea were quantified in vivo using non-contact dynamic Acoustic micro-Tapping Optical Coherence Elastography (AuT-OCE). The IOP-dependence of measured mechanical properties was explored in extracted whole globes following in vivo measurement. A nearly-incompressible transverse isotropic (NITI) model was used to reconstruct moduli from AuT-OCE data. Independently, cornea elastic moduli were also measured ex vivo with traditional, destructive mechanical tests (tensile extensometry and shear rheometry).
Our study demonstrates strong anisotropy of corneal elasticity in rabbits. The in-plane Young's modulus, computer as E=3u, was in the range of 20-44 MPa, whereas the out-of-plane shear modulus was in the range of 34-261 kPa. Both pressure-dependent ex vivo OCE and destructive mechanical tests performed on the same samples within an hour of euthanasia strongly support the results of AuT-OCE measurements.
Non-contact AuT-OCE can non-invasively quantify cornea anisotropic elastic properties in vivo.
As OCT is broadly accepted in Ophthalmology, these results suggest the potential for rapid translation of AuT-OCE into clinical practice. In addition, AuT-OCE can likely improve diagnostic criteria of ectatic corneal diseases, leading to early diagnosis, reduced complications, customized surgical treatment, and personalized biomechanical models of the eye.
用非接触式、非侵入性光学相干弹性成像技术在体内精确测量角膜弹性模量。
使用非接触式动态声学微敲击光学相干弹性成像技术（AuT-OCE）在体内对兔角膜的弹性特性（面内杨氏模量E以及面内剪切模量u和面外剪切模量G）进行量化。在体内测量后，对摘取的整个眼球进行研究，探讨测量的力学性能与眼压的相关性。使用近不可压缩横向各向同性（NITI）模型从AuT-OCE数据中重建模量。另外，还通过传统的破坏性力学测试（拉伸引伸计和剪切流变仪）在体外测量角膜弹性模量。
我们的研究表明兔角膜弹性具有很强的各向异性。计算得出的面内杨氏模量E = 3u，范围在20 - 44 MPa，而面外剪切模量范围在34 - 261 kPa。在安乐死一小时内对相同样本进行的压力依赖性体外OCE和破坏性力学测试都有力地支持了AuT-OCE测量结果。
非接触式AuT-OCE能够在体内非侵入性地量化角膜各向异性弹性特性。
由于光学相干断层扫描（OCT）在眼科已被广泛接受，这些结果表明AuT-OCE有快速转化为临床应用的潜力。此外，AuT-OCE可能会改善扩张性角膜疾病的诊断标准，从而实现早期诊断、减少并发症、定制手术治疗以及建立个性化的眼部生物力学模型。
