FINITE ELEMENT ANALYSIS OF THE MECHANICAL CHARACTERISTICS OF GLAUCOMA

Purpose: Construct a finite element model of the human eye to quantitatively analyze the mechanical characteristics of the human eye, especially the glaucoma damage process of the optic nerve head (ONH). Method: First, the geometry model of the human eye with nonuniform thickness was established based on a reasonable hypothesis and assumptions. Because the ONH is an important factor for glaucoma, we refine the structure of the ONH with lamina cribrosa. Then, mesh division was applied for finite element analysis. To simplify the complexity of the analysis, the materials of the model were assumed to be isotropic linear elastic materials, and physical properties such as Young’s modulus and Poisson’s ratio were set according to published literature. Next, proper constraints and loads were applied to the model and solved with a finite element method. Result: A finite element model of the human eye was created to simulate the mechanical characteristics of the eye structures under high intraocular pressure (IOP). The ONH depressed 1.057mm under 0.009MPa pressure to simulate high IOP. Conclusion: The constructed model is able to quantitatively simulate excavation of the optic disc and damage of the optic nerve. The result proved Houcheng Liang’s hypothesis about the ONH damage mechanism in glaucoma.

[1]  Nicola Bonora,et al.  The pathogenesis of retinal damage in blunt eye trauma: finite element modeling. , 2011, Investigative ophthalmology & visual science.

[2]  Joel D Stitzel,et al.  A nonlinear finite element model of the eye with experimental validation for the prediction of globe rupture. , 2002, Stapp car crash journal.

[3]  L. T. Kisielewicz,et al.  Simulation model of an eyeball based on finite element analysis on a supercomputer , 1999, The British journal of ophthalmology.

[4]  Yubo Fan,et al.  Mechanism of traumatic retinal detachment in blunt impact: a finite element study. , 2013, Journal of biomechanics.

[5]  J. Reddy.  An introduction to the finite element method , 1989 .

[6]  C. R. Ethier,et al.  Effects of Scleral Stiffness Properties on Optic Nerve Head Biomechanics , 2009, Annals of Biomedical Engineering.

[7]  S. Viswanathan,et al.  Effects of optic nerve injury, glaucoma, and neuroprotection on the survival, structure, and function of ganglion cells in the mammalian retina , 2008, The Journal of physiology.

[8]  J. Crowston,et al.  Definition of glaucoma: clinical and experimental concepts , 2012, Clinical & experimental ophthalmology.

[9]  H. A. Quigley,et al.  Open-angle glaucoma. , 1993, The New England journal of medicine.

[10]  J Flammer,et al.  Vascular dysregulation: a principal risk factor for glaucomatous damage? , 1999, Journal of glaucoma.

[11]  Ian A Sigal,et al.  An applet to estimate the IOP-induced stress and strain within the optic nerve head. , 2011, Investigative ophthalmology & visual science.

[12]  T. Newson,et al.  Mathematical modeling of the biomechanics of the lamina cribrosa under elevated intraocular pressures. , 2006, Journal of biomechanical engineering.

[13]  R W Flower,et al.  The mechanism of optic nerve damage in experimental acute intraocular pressure elevation. , 1980, Investigative ophthalmology & visual science.

[14]  J. Stevens,et al.  Mathematical modelling of the elastic properties of retina: A determination of Young's modulus , 1992, Eye.

[15]  Thao D Nguyen,et al.  Biomechanics of the human posterior sclera: age- and glaucoma-related changes measured using inflation testing. , 2012, Investigative ophthalmology & visual science.

[16]  Saeed Moaveni,et al.  Finite Element Analysis Theory and Application with ANSYS , 2007 .

[17]  Harinder Singh Sethi,et al.  Clinical Evaluation of Optic Nerve Head in Glaucoma , 2010 .

[18]  C. R. Ethier,et al.  Ocular biomechanics and biotransport. , 2004, Annual review of biomedical engineering.

[19]  J. Grimm,et al.  A few good responses: which mechanical effects of IOP on the ONH to study? , 2012, Investigative ophthalmology & visual science.

[20]  Ian A Sigal,et al.  Finite element modeling of the human sclera: influence on optic nerve head biomechanics and connections with glaucoma. , 2011, Experimental eye research.

[21]  Louis R Pasquale,et al.  Genetic variants associated with optic nerve vertical cup-to-disc ratio are risk factors for primary open angle glaucoma in a US Caucasian population. , 2011, Investigative ophthalmology & visual science.

[22]  Ning-Jiun Jan,et al.  Eye-specific IOP-induced displacements and deformations of human lamina cribrosa. , 2014, Investigative ophthalmology & visual science.

[23]  P. Mackenzie,et al.  Optic nerve head and peripapillary morphometrics in myopic glaucoma. , 2014, Investigative ophthalmology & visual science.

[24]  Hiroshi Ishikawa,et al.  A Method to Estimate Biomechanics and Mechanical Properties of Optic Nerve Head Tissues From Parameters Measurable Using Optical Coherence Tomography , 2014, IEEE Transactions on Medical Imaging.

[25]  Brad Fortune,et al.  Evaluation of retinal nerve fiber layer thickness and axonal transport 1 and 2 weeks after 8 hours of acute intraocular pressure elevation in rats. , 2014, Investigative ophthalmology & visual science.