PURPOSE. The purpose of this study was to quantify the biomechanical response of human posterior ocular tissues from donors of various racioethnic groups to better understand how differences in these properties may play a role in the racioethnic health disparities known to exist in glaucoma. METHODS. Sequential digital image correlation (S-DIC) was used to measure the pressure-induced surface deformations of 23 normal human posterior poles from three racioethnic groups: African descent (AD), European descent (ED), and Hispanic ethnicity (HIS). Regional in-plane principal strains were compared across three zones: the optic nerve stump (ONS), the peripapillary (PP) sclera, and non-PP sclera. RESULTS. The PP scleral tensile strains were found to be lower for ED eyes compared with AD and HIS eyes at 15 mm Hg (P = 0.024 and 0.039, respectively). The mean compressive strains were significantly higher for AD eyes compared with ED eyes at 15 mm Hg (P = 0.018). We also found that the relationship between tensile strain and pressure was significant for those of ED and HIS eyes (P < 0.001 and P = 0.004, respectively), whereas it was not significant for those of AD (P = 0.392). CONCLUSIONS. Our results suggest that, assuming glaucomatous nerve loss is caused by mechanical strains in the vicinity of the optic nerve head, the mechanism of increased glaucoma prevalence may be different in those of AD versus HIS. Our ONS strain analysis also suggested that it may be important to account for ONS geometry and material properties in future scleral biomechanical analysis.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/626003 |
| Date | 28 August 2017 |
| Creators | Tamimi, Ehab A., Pyne, Jeffrey D., Muli, Dominic K., Axman, Katelyn F., Howerton, Stephen J., Davis, Matthew R., Girkin, Christopher A., Vande Geest, Jonathan P. |
| Contributors | Univ Arizona, Dept Aerosp & Mech Engn, Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, Department of Mechanical Engineering, University of California Berkeley, Berkeley, California, United States, Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States, Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona, United States, Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona, United States, Department of Ophthalmology, University of Alabama Birmingham, Birmingham, Alabama, United States, Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 5McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 6Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States 7Louis J. Fox Center for Vision Restoration, University of Pittsburgh, Pennsylvania, United States |
| Publisher | ASSOC RESEARCH VISION OPHTHALMOLOGY INC |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | Article |
| Rights | Copyright © 2017 The Authors. This work is licensed under a Creative Commons Attribution 4.0 International License. |
| Relation | http://iovs.arvojournals.org/article.aspx?doi=10.1167/iovs.17-22141 |
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