Glaucoma Risk Factors: Intraocular Pressure

Loewen, Nils A.; Tanna, Angelo P.

doi:10.1007/978-0-387-76700-0_3

Cited by 2 publications

(1 citation statement)

References 170 publications

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“…The model's relative simplicity should also facilitate future clinical trials, as it requires a single noncontact measurement, obtained within seconds, to estimate G and µ. While other clinical tools, such as the Ocular Response Analyzer (ORA), have been used clinically to infer both corneal stiffness and IOP 46 , sufficient measurement error 47 , in addition to patient discomfort 48 , hinder widespread use. Further, the relationship between in vivo applanation and corneal Young's Modulus remains unclear 49,50 .…”

Section: Discussionmentioning

confidence: 99%

Nearly-incompressible transverse isotropy (NITI) of cornea elasticity: model and experiments with acoustic micro-tapping OCE

Pitre

Kirby

et al. 2020

Sci Rep

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The cornea provides the largest refractive power for the human visual system. Its stiffness, along with intraocular pressure (IOP), are linked to several pathologies, including keratoconus and glaucoma. Although mechanical tests can quantify corneal elasticity ex vivo, they cannot be used clinically. Dynamic optical coherence elastography (OCE), which launches and tracks shear waves to estimate stiffness, provides an attractive non-contact probe of corneal elasticity. To date, however, OCE studies report corneal moduli around tens of kPa, orders-of-magnitude less than those (few MPa) obtained by tensile/inflation testing. This large discrepancy impedes OCE’s clinical adoption. Based on corneal microstructure, we introduce and fully characterize a nearly-incompressible transversely isotropic (NITI) model depicting corneal biomechanics. We show that the cornea must be described by at least two shear moduli, contrary to current single-modulus models, decoupling tensile and shear responses. We measure both as a function of IOP in ex vivo porcine cornea, obtaining values consistent with both tensile and shear tests. At pressures above 30 mmHg, the model begins to fail, consistent with non-linear changes in cornea at high IOP.

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