Biomechanical Effects of Intraocular Pressure Elevation on Optic Nerve/Lamina Cribrosa before and after Peripapillary Scleral Collagen Cross-Linking

Thornton, Ivey L.; Dupps, William J.; Roy, Abhijit Sinha; Krueger, Ronald R.

doi:10.1167/iovs.08-1960

Cited by 56 publications

(48 citation statements)

References 31 publications

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“…Zeimer et al [41] observed a decrease in ONH compliance in 15 human glaucomatous postmortem eyes while the visual field worsened indicating a stiffening of the mechanical support of the ONH. However, there is also evidence that stiffening, especially of the ppSc, might represent a compensatory response involving an attempt by the ECM to resist the increased stress and strain imposed by elevated IOP in disease predisposition but not in early induced glaucoma models [42,43] .…”

Section: Discussionmentioning

confidence: 99%

Diabetes Mellitus Affects Biomechanical Properties of the Optic Nerve Head in the Rat

et al. 2011

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Background: To investigate the effect of diabetes on the biomechanical behavior of the optic nerve head (ONH) and the peripapillary sclera (ppSc) in streptozocine-induced diabetic rats. Methods: Diabetes mellitus was induced in 20 Wistar rats using streptozocine. Twenty-five nondiabetic rats served as controls. Eyes were enucleated after 12 weeks and 2 strips of one eye were prepared containing ONH or ppSc. The stress-strain relation was measured in the stress range of 0.05–10 MPa using a biomaterial tester. Results: At 5% strain the stress of the ONH in diabetic rats was 897 ± 295 kPa and in the control group it was 671 ± 246 kPa; there was a significant difference between both groups (p = 0.011). The stress of the diabetic ppSc (574 ± 185 kPa) increased compared to that of the nondiabetic ppSc (477 ± 171 kPa), but this did not reach statistical significance (p = 0.174). The calculated tangent modulus at 5% strain was 11.79 MPa in the diabetic ONH and 8.77 MPa in the nondiabetic ONH; there was a significant difference between both groups (p = 0.006). The calculated tangent modulus at 5% strain was 7.17 MPa in the diabetic ppSc and 6.12 MPa in the nondiabetic ppSc, without a statistically significant difference (p = 0.09). Conclusion: In contrast to the ppSc, the ONH of diabetic rats showed a significant increase in stiffness compared to nondiabetic rats, which might be explained by nonenzymatic collagen cross-linking mediated by advanced glycation end products due to high blood glucose levels in diabetes. Further studies are needed to investigate if these biomechanical changes represent a detrimental risk factor for intraocular pressure regulation in diabetic glaucoma patients.

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Section: Discussionmentioning

confidence: 99%

Diabetes Mellitus Affects Biomechanical Properties of the Optic Nerve Head in the Rat

et al. 2011

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“…Exposure to riboflavin activated by ultraviolet light (Wollensak et al, 2003) or glyceraldehyde (GA) treatment (Thornton et al, 2009;Wollensak and Iomdina, 2008) stiffen the cornea and sclera, altering their stress-strain behavior without significant damage to the retina or other ocular structures. To test this approach, we produced experimental IOP elevation in CD1 mice after three subconjunctival injections of 0.5 M GA.…”

Section: Therapy Involving the Noncellular Componentsmentioning

confidence: 99%

The contribution of the sclera and lamina cribrosa to the pathogenesis of glaucoma

Quigley

2015

Progress in Brain Research

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“…Viscoelastic tensile creep and relaxation tests have also been conducted on these tissues [21,[23][24][25]. Inflation tests wherein whole [19,[26][27][28][29][30][31] or partial globes [32][33][34][35][36][37] are subjected to increasing levels of pressure while the scleral surface is imaged have been used to study the sclera's strain field, viscoelasticity, and the effects of various eye disease treatments. In general, these types of tests, particularly those on whole globes, are more physiologically realistic than tests on excised specimens.…”

Section: Introductionmentioning

confidence: 99%

Shear Behavior of Bovine Scleral Tissue

Argento

Kim

Rozsa

et al. 2014

Journal of Biomechanical Engineering

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Ocular tissue properties have been widely studied in tension and compression for humans and a variety of animals. However, direct shear testing of the tissues of the sclera appear to be absent from the literature even though modeling, analyses, and anatomical studies have indicated that shear may play a role in the etiology of primary open angle glaucoma (POAG). In this work, the mechanical behavior of bovine scleral tissue in shear has been studied in both out-of-plane and in-plane modes of deformation. Stress-strain and relaxation tests were conducted on tissue specimens at controlled temperature and hydration focusing on trends related to specimen location and orientation. There was generally found to be no significant effect of specimen orientation and angular location in the globe on shear stiffness in both modes. The in-plane response, which is the primary load carrying mode, was found to be substantially stiffer than the out-of-plane mode. Also, within the in-plane studies, tissue further from the optic nerve was stiffer than the near tissue. The viscosity coefficient of the tissue varied insignificantly with distance from the optic nerve, but overall was much higher in-plane than out-of-plane.

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Biomechanical Effects of Intraocular Pressure Elevation on Optic Nerve/Lamina Cribrosa before and after Peripapillary Scleral Collagen Cross-Linking

Abstract: Stiffening of the peripapillary scleral ring reduces the biomechanical sensitivity of the ON/LC complex to IOP elevation and may represent a novel mechanism for neuroprotection in glaucoma.

Cited by 56 publications

References 31 publications

Diabetes Mellitus Affects Biomechanical Properties of the Optic Nerve Head in the Rat

Diabetes Mellitus Affects Biomechanical Properties of the Optic Nerve Head in the Rat

The contribution of the sclera and lamina cribrosa to the pathogenesis of glaucoma

Shear Behavior of Bovine Scleral Tissue

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