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Ashofteh Yazdi A, Melchor J, Torres J, Faris I, Callejas A, Gonzalez-Andrades M, Rus G. Characterization of non-linear mechanical behavior of the cornea. Sci Rep 2020; 10:11549. [PMID: 32665558 PMCID: PMC7360609 DOI: 10.1038/s41598-020-68391-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 06/23/2020] [Indexed: 11/24/2022] Open
Abstract
The objective of this study was to evaluate which hyperelastic model could best describe the non-linear mechanical behavior of the cornea, in order to characterize the capability of the non-linear model parameters to discriminate structural changes in a damaged cornea. Porcine corneas were used, establishing two different groups: control (non-treated) and NaOH-treated (damaged) corneas (n = 8). NaOH causes a chemical burn to the corneal tissue, simulating a disease associated to structural damage of the stromal layer. Quasi-static uniaxial tensile tests were performed in nasal-temporal direction immediately after preparing corneal strips from the two groups. Three non-linear hyperelastic models (i.e. Hamilton-Zabolotskaya model, Ogden model and Mooney-Rivlin model) were fitted to the stress–strain curves obtained in the tensile tests and statistically compared. The corneas from the two groups showed a non-linear mechanical behavior that was best described by the Hamilton-Zabolotskaya model, obtaining the highest coefficient of determination (R2 > 0.95). Moreover, Hamilton-Zabolotskaya model showed the highest discriminative capability of the non-linear model parameter (Parameter A) for the tissue structural changes between the two sample groups (p = 0.0005). The present work determines the best hyperelastic model with the highest discriminative capability in description of the non-linear mechanical behavior of the cornea.
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Affiliation(s)
- A Ashofteh Yazdi
- Ultrasonics Lab, Department of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071, Granada, Spain.,Department of Biomedical Engineering, Islamic Azad University, Mashhad Branch, Mashhad, Iran
| | - J Melchor
- Department of Statistics and Operations Research, University of Granada, Granada, Spain.,Instituto de Investigación Biosanitaria, Ibs.GRANADA, Granada, Spain.,Excellence Research Unit, "Modelling Nature" (MNat), University of Granada, Granada, Spain
| | - J Torres
- Ultrasonics Lab, Department of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071, Granada, Spain.,Instituto de Investigación Biosanitaria, Ibs.GRANADA, Granada, Spain
| | - I Faris
- Ultrasonics Lab, Department of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071, Granada, Spain.,Instituto de Investigación Biosanitaria, Ibs.GRANADA, Granada, Spain
| | - A Callejas
- Ultrasonics Lab, Department of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071, Granada, Spain.,Instituto de Investigación Biosanitaria, Ibs.GRANADA, Granada, Spain
| | - M Gonzalez-Andrades
- Maimonides Biomedical Research Institute of Cordoba (IMIBIC), Department of Ophthalmology, Reina Sofia University Hospital and University of Cordoba, Edificio IMIBIC, Av. Menéndez Pidal, s/n. 14004, Cordoba, Spain. .,Massachusetts Eye and Ear and Schepens Eye Research Institute, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
| | - G Rus
- Ultrasonics Lab, Department of Structural Mechanics, University of Granada, Politécnico de Fuentenueva, 18071, Granada, Spain. .,Instituto de Investigación Biosanitaria, Ibs.GRANADA, Granada, Spain. .,Excellence Research Unit, "Modelling Nature" (MNat), University of Granada, Granada, Spain.
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