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The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties
PURPOSE: The purpose of this study was to isolate the structural components of the ex vivo porcine iris tissue and to determine their biomechanical properties. METHODS: The porcine stroma and dilator tissues were separated, and their dimensions were assessed using optical coherence tomography (OCT)....
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Association for Research in Vision and Ophthalmology
2023
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10561784/ https://www.ncbi.nlm.nih.gov/pubmed/37796489 http://dx.doi.org/10.1167/iovs.64.13.11 |
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author | Tan, Royston K. Y. Panda, Satish K. Braeu, Fabian A. Muralidharan, Arumugam R. Nongpiur, Monisha E. Chan, Anita S. Y. Aung, Tin Najjar, Raymond P. Girard, Michaël J. A. |
author_facet | Tan, Royston K. Y. Panda, Satish K. Braeu, Fabian A. Muralidharan, Arumugam R. Nongpiur, Monisha E. Chan, Anita S. Y. Aung, Tin Najjar, Raymond P. Girard, Michaël J. A. |
author_sort | Tan, Royston K. Y. |
collection | PubMed |
description | PURPOSE: The purpose of this study was to isolate the structural components of the ex vivo porcine iris tissue and to determine their biomechanical properties. METHODS: The porcine stroma and dilator tissues were separated, and their dimensions were assessed using optical coherence tomography (OCT). The stroma underwent flow test (n = 32) to evaluate for permeability using Darcy's Law (ΔP = 2000 Pa, A = 0.0391 mm(2)), and both tissues underwent stress relaxation experiments (ε = 0.5 with initial ramp of δε = 0.1) to evaluate for their viscoelastic behaviours (n = 28). Viscoelasticity was characterized by the parameters β (half width of the Gaussian distribution), τ(m) (mean relaxation time constant), E(0) (instantaneous modulus), and E(∞) (equilibrium modulus). RESULTS: For the stroma, the hydraulic permeability was 9.49 ± 3.05 × 10(−6) mm(2)/Pa · s, and the viscoelastic parameters were β = 2.50 ± 1.40, and τ(m) = 7.43 ± 4.96 s, with the 2 moduli calculated to be E(0) = 14.14 ± 6.44 kPa and E(∞) = 6.08 ± 2.74 kPa. For the dilator tissue, the viscoelastic parameters were β = 2.06 ± 1.33 and τ(m) = 1.28 ± 1.27 seconds, with the 2 moduli calculated to be E(0) = 9.16 ± 3.03 kPa and E(∞) = 5.54 ± 1.98 kPa. CONCLUSIONS: We have established a new protocol to evaluate the biomechanical properties of the structural layers of the iris. Overall, the stroma was permeable and exhibited smaller moduli than those of the dilator muscle. An improved characterization of iris biomechanics may form the basis to further our understanding of angle closure glaucoma. |
format | Online Article Text |
id | pubmed-10561784 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2023 |
publisher | The Association for Research in Vision and Ophthalmology |
record_format | MEDLINE/PubMed |
spelling | pubmed-105617842023-10-10 The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties Tan, Royston K. Y. Panda, Satish K. Braeu, Fabian A. Muralidharan, Arumugam R. Nongpiur, Monisha E. Chan, Anita S. Y. Aung, Tin Najjar, Raymond P. Girard, Michaël J. A. Invest Ophthalmol Vis Sci Glaucoma PURPOSE: The purpose of this study was to isolate the structural components of the ex vivo porcine iris tissue and to determine their biomechanical properties. METHODS: The porcine stroma and dilator tissues were separated, and their dimensions were assessed using optical coherence tomography (OCT). The stroma underwent flow test (n = 32) to evaluate for permeability using Darcy's Law (ΔP = 2000 Pa, A = 0.0391 mm(2)), and both tissues underwent stress relaxation experiments (ε = 0.5 with initial ramp of δε = 0.1) to evaluate for their viscoelastic behaviours (n = 28). Viscoelasticity was characterized by the parameters β (half width of the Gaussian distribution), τ(m) (mean relaxation time constant), E(0) (instantaneous modulus), and E(∞) (equilibrium modulus). RESULTS: For the stroma, the hydraulic permeability was 9.49 ± 3.05 × 10(−6) mm(2)/Pa · s, and the viscoelastic parameters were β = 2.50 ± 1.40, and τ(m) = 7.43 ± 4.96 s, with the 2 moduli calculated to be E(0) = 14.14 ± 6.44 kPa and E(∞) = 6.08 ± 2.74 kPa. For the dilator tissue, the viscoelastic parameters were β = 2.06 ± 1.33 and τ(m) = 1.28 ± 1.27 seconds, with the 2 moduli calculated to be E(0) = 9.16 ± 3.03 kPa and E(∞) = 5.54 ± 1.98 kPa. CONCLUSIONS: We have established a new protocol to evaluate the biomechanical properties of the structural layers of the iris. Overall, the stroma was permeable and exhibited smaller moduli than those of the dilator muscle. An improved characterization of iris biomechanics may form the basis to further our understanding of angle closure glaucoma. The Association for Research in Vision and Ophthalmology 2023-10-05 /pmc/articles/PMC10561784/ /pubmed/37796489 http://dx.doi.org/10.1167/iovs.64.13.11 Text en Copyright 2023 The Authors https://creativecommons.org/licenses/by-nc-nd/4.0/This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. |
spellingShingle | Glaucoma Tan, Royston K. Y. Panda, Satish K. Braeu, Fabian A. Muralidharan, Arumugam R. Nongpiur, Monisha E. Chan, Anita S. Y. Aung, Tin Najjar, Raymond P. Girard, Michaël J. A. The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties |
title | The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties |
title_full | The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties |
title_fullStr | The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties |
title_full_unstemmed | The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties |
title_short | The Structural Layers of the Porcine Iris Exhibit Inherently Different Biomechanical Properties |
title_sort | structural layers of the porcine iris exhibit inherently different biomechanical properties |
topic | Glaucoma |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10561784/ https://www.ncbi.nlm.nih.gov/pubmed/37796489 http://dx.doi.org/10.1167/iovs.64.13.11 |
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