the effects of curvature and thickness of cornea-based structures assessed by finite element...
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Outline Introduction Methods Results ConclusionTRANSCRIPT
![Page 1: The effects of curvature and thickness of cornea-based structures assessed by finite element modeling and optical coherence elastography Zhaolong Han,](https://reader036.vdocuments.us/reader036/viewer/2022062523/5a4d1adf7f8b9ab059976984/html5/thumbnails/1.jpg)
The effects of curvature and thickness of cornea-based structures assessed by finite element modeling and optical
coherence elastographyZhaolong Han, Jiasong Li, Manmohan Singh, Salavat R. Aglyamov,
Chen Wu, Chih-hao Liu, and Kirill V. Larin
Department of Biomedical Engineering, University of Houston
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Outline• Introduction• Methods• Results• Conclusion
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Introduction• One approach for extracting the biomechanical properties of
the cornea is by assessing the propagation of an elastic wave by Optical Coherence Elastography (OCE).
• However, the wave models currently used to quantify the biomechanical properties are based on the assumption of a thin plate in half-space, which does not incorporate the effects of the thickness and curvature of the cornea.
• We have performed finite element (FE) simulations combined with OCE experiments in order to understand the influence of the corneal curvature and thickness on the group velocity of an elastic wave.
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Methods: OCE setup
OCE set up
J. Li, et al, "Dynamic optical coherence tomography measurements of elastic wave propagation in tissue-mimicking phantoms and mouse cornea in vivo," J Biomed Opt 18(12), (2013).
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Methods: cornea-shape samples
Contact lensAlcon Inc., TX, USA;
67% delefilcon A, 33% waterPhantom strip on a water balloon
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Methods: FEM models
Four types of cornea-like structures
FEM model
Excitation
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Results: radius effect
Both FEM and OCE experiments demonstrate that group velocity decreases as radius of curvature increases.
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Results: thickness effect
Both FEM and OCE experiments demonstrate that group velocity increases with thickness.
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Results: FEM displacement map
Different FEM simulated displacement contour maps (2D and 3D views) at t=3.2 ms for different cornea-shape under the same Young’s modulus E=60kPa.
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Results: FEM displacements
FEM simulated vertical displacement temporal profiles obtained at 0.16 mm, 0.80 mm, 1.44 mm and 2.08 mm away from the central excitation for the four types of structures.
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Conclusions• In cornea-shape structure, the group velocity
decreases as the radius of curvature increases, and that the velocity increases as the thickness of the sample increases.
• The curvature and thickness must be considered when improving wave models used for reconstructing the biomechanical properties of the cornea from OCE measurements.
• Combining OCE with FEM is a promising method to quantitatively reconstruct elasticity in cornea.
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Thank you!