{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,11]],"date-time":"2026-09-11T01:47:11Z","timestamp":1789091231539,"version":"build-2803163510"},"reference-count":55,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2025,5,29]],"date-time":"2025-05-29T00:00:00Z","timestamp":1748476800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"National Institutes of Health (NIH)","award":["EY008313"],"award-info":[{"award-number":["EY008313"]}]},{"name":"National Institutes of Health (NIH)","award":["EY000331"],"award-info":[{"award-number":["EY000331"]}]},{"name":"Research to Prevent Blindness","award":["EY008313"],"award-info":[{"award-number":["EY008313"]}]},{"name":"Research to Prevent Blindness","award":["EY000331"],"award-info":[{"award-number":["EY000331"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Bioengineering"],"abstract":"<jats:p>Previous models of extraocular mechanics have often assumed isotropic properties for ocular tissues, despite evidence indicating anisotropy in the optic nerve sheath (ONS). To investigate this further, we developed a finite element model (FEM) of horizontal eye rotation using MRI data from a living subject with normal tension glaucoma. Mechanical properties were derived from tensile tests on 17 post-mortem human eyes, revealing previously unrecognized anisotropic characteristics in the ONS. We simulated \u00b132\u00b0 horizontal eye rotations and compared isotropic versus anisotropic ONS properties using the Holzapfel model. Strain distributions in the optic nerve (ON) were analyzed using ABAQUS 2024 software. During 32\u00b0 adduction, stress and strain were concentrated at the ONS-sclera junction, reaching 8 MPa and 40% with isotropic properties, and 15 MPa and 30% with anisotropic properties. In contrast, during 32\u00b0 abduction, stress was lower and strain was higher in the isotropic case (6 MPa and 30%) compared to the anisotropic case (12 MPa and 25%). Increased intraocular and intracranial pressures had minimal impact on the mechanical responses. These findings suggest that the anisotropic properties of the ONS increase stress concentration at the optic disc while reducing strain during eye movements, offering new insights into ocular biomechanics. A novel phenomenon emerged from the simulations: during larger ductions, the peripapillary Bruch\u2019s membrane is predicted to wrinkle, forming undulations with an approximately 20 \u03bcm amplitude and 100 \u03bcm wavelength at its interface with the retina and choroid.<\/jats:p>","DOI":"10.3390\/bioengineering12060587","type":"journal-article","created":{"date-parts":[[2025,5,29]],"date-time":"2025-05-29T07:46:26Z","timestamp":1748504786000},"page":"587","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Finite Element Model of the Effect of Optic Nerve Sheath Anisotropy on Ocular Loading During Horizontal Duction"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9822-8545","authenticated-orcid":false,"given":"Somaye","family":"Jafari","sequence":"first","affiliation":[{"name":"Department of Ophthalmology, Stein Eye Institute, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shengqiang","family":"Cai","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of California, San Diego, CA 92093, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9662-5352","authenticated-orcid":false,"given":"Joseph L.","family":"Demer","sequence":"additional","affiliation":[{"name":"Department of Ophthalmology, Stein Eye Institute, Los Angeles, CA 90095, USA"},{"name":"Neuroscience Interdepartmental Program, University of California, Los Angeles, CA 90095, USA"},{"name":"Department of Neurology, University of California, Los Angeles, CA 90095, USA"},{"name":"Department of Bioengineering, University of California, Los Angeles, CA 90095, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,5,29]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1826","DOI":"10.1167\/iovs.15-18718","article-title":"Optic Nerve Sheath as a Novel Mechanical Load on the Globe in Ocular Duction","volume":"57","author":"Demer","year":"2016","journal-title":"Investig. 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