Estimating Human Trabecular Meshwork Stiffness by Numerical Modeling and Advanced OCT Imaging.

Autor:	Wang K; Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States., Johnstone MA; Department of Ophthalmology, University of Washington, Seattle, Washington, United States., Xin C; Department of Bioengineering, University of Washington, Seattle, Washington, United States., Song S; Department of Bioengineering, University of Washington, Seattle, Washington, United States., Padilla S; Department of Ophthalmology, University of Washington, Seattle, Washington, United States., Vranka JA; Department of Ophthalmology, Casey Eye Institute, Portland, Oregon, United States., Acott TS; Department of Ophthalmology, Casey Eye Institute, Portland, Oregon, United States., Zhou K; Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States., Schwaner SA; Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States., Wang RK; Department of Bioengineering, University of Washington, Seattle, Washington, United States., Sulchek T; George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States., Ethier CR; Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States.; George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, United States.
Jazyk:	angličtina
Zdroj:	Investigative ophthalmology & visual science [Invest Ophthalmol Vis Sci] 2017 Sep 01; Vol. 58 (11), pp. 4809-4817.
DOI:	10.1167/iovs.17-22175
Abstrakt:	Purpose: The purpose of this study was to estimate human trabecular meshwork (hTM) stiffness, thought to be elevated in glaucoma, using a novel indirect approach, and to compare results with direct en face atomic force microscopy (AFM) measurements. Methods: Postmortem human eyes were perfused to measure outflow facility and identify high- and low-flow regions (HF, LF) by tracer. Optical coherence tomography (OCT) images were obtained as Schlemm's canal luminal pressure was directly manipulated. TM stiffness was deduced by an inverse finite element modeling (FEM) approach. A series of AFM forcemaps was acquired along a line traversing the anterior angle on a radially cut flat-mount corneoscleral wedge with TM facing upward. Results: The elastic modulus of normal hTM estimated by inverse FEM was 70 ± 20 kPa (mean ± SD), whereas glaucomatous hTM was slightly stiffer (98 ± 19 kPa). This trend was consistent with TM stiffnesses measured by AFM: normal hTM stiffness = 1.37 ± 0.56 kPa, which was lower than glaucomatous hTM stiffness (2.75 ± 1.19 kPa). None of these differences were statistically significant. TM in HF wedges was softer than that in LF wedges for both normal and glaucomatous eyes based on the inverse FEM approach but not by AFM. Outflow facility was significantly correlated with TM stiffness estimated by FEM in six human eyes (P = 0.018). Conclusions: TM stiffness is higher, but only modestly so, in glaucomatous patients. Outflow facility in both normal and glaucomatous human eyes appears to associate with TM stiffness. This evidence motivates further studies to investigate factors underlying TM biomechanical property regulation.
Databáze:	MEDLINE
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