Cargando…
Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues
PURPOSE: The laminar region of the optic nerve head (ONH), thought to be the site of damage to the retinal ganglion cell axons in glaucoma, is continuously loaded on its anterior and posterior surfaces by dynamic intraocular pressure (IOP) and orbital cerebrospinal fluid pressure (CSFP), respectivel...
Autores principales: | , , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Association for Research in Vision and Ophthalmology
2022
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9587471/ https://www.ncbi.nlm.nih.gov/pubmed/36255364 http://dx.doi.org/10.1167/iovs.63.11.14 |
_version_ | 1784813908686536704 |
---|---|
author | Karimi, Alireza Razaghi, Reza Rahmati, Seyed Mohammadali Girkin, Christopher A. Downs, J. Crawford |
author_facet | Karimi, Alireza Razaghi, Reza Rahmati, Seyed Mohammadali Girkin, Christopher A. Downs, J. Crawford |
author_sort | Karimi, Alireza |
collection | PubMed |
description | PURPOSE: The laminar region of the optic nerve head (ONH), thought to be the site of damage to the retinal ganglion cell axons in glaucoma, is continuously loaded on its anterior and posterior surfaces by dynamic intraocular pressure (IOP) and orbital cerebrospinal fluid pressure (CSFP), respectively. Thus, translaminar pressure (TLP; TLP = IOP-CSFP) has been proposed as a glaucoma risk factor. METHODS: Three eye-specific finite element models of the posterior human eye were constructed, including full 3D microstructures of the load-bearing lamina cribrosa (LC) with interspersed laminar neural tissues (NTs), and heterogeneous, anisotropic, hyperelastic material formulations for the surrounding peripapillary sclera and adjacent pia. ONH biomechanical responses were simulated using three combinations of IOP and CSFP loadings consistent with posture change from sitting to supine. RESULTS: Results show that tensile, compressive, and shear stresses and strains in the ONH were higher in the supine position compared to the sitting position (P < 0.05). In addition, LC beams bear three to five times more TLP-driven stress than interspersed laminar NT, whereas laminar NT exhibit three to five times greater strain than supporting LC (P < 0.05). Compared with CSFP, IOP drove approximately four times greater stress and strain in the LC, NT, and peripapillary sclera, normalized per mm Hg pressure change. In addition, IOP drove approximately three-fold greater scleral canal expansion and anterior-posterior laminar deformation than CSFP per mm Hg (P < 0.05). CONCLUSIONS: Whereas TLP has been hypothesized to play a prominent role in ONH biomechanics, the IOP and CSFP effects are not equivalent, as IOP-driven stress, strain, and deformation play a more dominant role than CSFP effects. |
format | Online Article Text |
id | pubmed-9587471 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | The Association for Research in Vision and Ophthalmology |
record_format | MEDLINE/PubMed |
spelling | pubmed-95874712022-10-23 Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues Karimi, Alireza Razaghi, Reza Rahmati, Seyed Mohammadali Girkin, Christopher A. Downs, J. Crawford Invest Ophthalmol Vis Sci Glaucoma PURPOSE: The laminar region of the optic nerve head (ONH), thought to be the site of damage to the retinal ganglion cell axons in glaucoma, is continuously loaded on its anterior and posterior surfaces by dynamic intraocular pressure (IOP) and orbital cerebrospinal fluid pressure (CSFP), respectively. Thus, translaminar pressure (TLP; TLP = IOP-CSFP) has been proposed as a glaucoma risk factor. METHODS: Three eye-specific finite element models of the posterior human eye were constructed, including full 3D microstructures of the load-bearing lamina cribrosa (LC) with interspersed laminar neural tissues (NTs), and heterogeneous, anisotropic, hyperelastic material formulations for the surrounding peripapillary sclera and adjacent pia. ONH biomechanical responses were simulated using three combinations of IOP and CSFP loadings consistent with posture change from sitting to supine. RESULTS: Results show that tensile, compressive, and shear stresses and strains in the ONH were higher in the supine position compared to the sitting position (P < 0.05). In addition, LC beams bear three to five times more TLP-driven stress than interspersed laminar NT, whereas laminar NT exhibit three to five times greater strain than supporting LC (P < 0.05). Compared with CSFP, IOP drove approximately four times greater stress and strain in the LC, NT, and peripapillary sclera, normalized per mm Hg pressure change. In addition, IOP drove approximately three-fold greater scleral canal expansion and anterior-posterior laminar deformation than CSFP per mm Hg (P < 0.05). CONCLUSIONS: Whereas TLP has been hypothesized to play a prominent role in ONH biomechanics, the IOP and CSFP effects are not equivalent, as IOP-driven stress, strain, and deformation play a more dominant role than CSFP effects. The Association for Research in Vision and Ophthalmology 2022-10-18 /pmc/articles/PMC9587471/ /pubmed/36255364 http://dx.doi.org/10.1167/iovs.63.11.14 Text en Copyright 2022 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 Karimi, Alireza Razaghi, Reza Rahmati, Seyed Mohammadali Girkin, Christopher A. Downs, J. Crawford Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues |
title | Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues |
title_full | Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues |
title_fullStr | Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues |
title_full_unstemmed | Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues |
title_short | Relative Contributions of Intraocular and Cerebrospinal Fluid Pressures to the Biomechanics of the Lamina Cribrosa and Laminar Neural Tissues |
title_sort | relative contributions of intraocular and cerebrospinal fluid pressures to the biomechanics of the lamina cribrosa and laminar neural tissues |
topic | Glaucoma |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9587471/ https://www.ncbi.nlm.nih.gov/pubmed/36255364 http://dx.doi.org/10.1167/iovs.63.11.14 |
work_keys_str_mv | AT karimialireza relativecontributionsofintraocularandcerebrospinalfluidpressurestothebiomechanicsofthelaminacribrosaandlaminarneuraltissues AT razaghireza relativecontributionsofintraocularandcerebrospinalfluidpressurestothebiomechanicsofthelaminacribrosaandlaminarneuraltissues AT rahmatiseyedmohammadali relativecontributionsofintraocularandcerebrospinalfluidpressurestothebiomechanicsofthelaminacribrosaandlaminarneuraltissues AT girkinchristophera relativecontributionsofintraocularandcerebrospinalfluidpressurestothebiomechanicsofthelaminacribrosaandlaminarneuraltissues AT downsjcrawford relativecontributionsofintraocularandcerebrospinalfluidpressurestothebiomechanicsofthelaminacribrosaandlaminarneuraltissues |