Large Scale Voxel-Based Finite Element Modeling of Normal and Early Glaucomatous Monkey Lamina Cribrosa

2008 ◽  
Author(s):  
Sanjay Kodiyalam ◽  
Michael D. Roberts ◽  
Ian A. Sigal ◽  
Richard T. Hart ◽  
Claude F. Burgoyne ◽  
...  
Keyword(s):  
Finite Element ◽  
Intraocular Pressure ◽  
Connective Tissue ◽  
Large Scale ◽  
Lamina Cribrosa ◽  
Posterior Pole ◽  
Stress And Strain ◽  
Structural Support ◽  
Elevated Intraocular Pressure ◽  
Related Stress

Glaucoma is a leading cause of blindness worldwide. Some of the chief clinical hallmarks of glaucoma are the permanent posterior cupping of the optic nerve head, in the posterior pole of the eye, and the accompanying damage to the lamina cribrosa — the fenestrated structure of connective tissue spanning the scleral canal that provides structural support to the axon bundles passing through it. While elevated intraocular pressure (IOP) is associated with this disease, its role remains unclear. It has been hypothesized that IOP-related stress and strain within the laminar connective tissue (LCT) underlie the onset and progression of glaucoma [1] and that they may be used to predict the location of axonal insult and the pattern of damage within the LCT.

scholarly journals Biomechanical research into lamina cribrosa in glaucoma

2020 ◽  
Vol 7 (8) ◽  
pp. 1277-1279
Author(s):  
Long Li ◽  
Fan Song
Keyword(s):  
Public Health ◽  
Intraocular Pressure ◽  
Lamina Cribrosa ◽  
Health Challenge ◽  
Elevated Intraocular Pressure ◽  
Mechanical Models ◽  
Public Health Challenge ◽  
Further Development ◽  
Open Issues ◽  
Irreversible Blindness

Summary Glaucoma, a leading cause of irreversible blindness, poses a considerable public health challenge and burden. Mechanical models of the lamina cribrosa under elevated intraocular pressure at different scales, contributing significantly to uncovering the glaucomatous pathogenesis, are discussed. Meanwhile, the open issues and avenues for further development are highlighted.

SIMULATING THE EFFECTS OF ELEVATED INTRAOCULAR PRESSURE ON OCULAR STRUCTURES USING A GLOBAL FINITE ELEMENT MODEL OF THE HUMAN EYE

2017 ◽  
Vol 17 (02) ◽  
pp. 1750038 ◽  
Author(s):  
PEISHAN DAI ◽  
YALI ZHAO ◽  
HANWEI SHENG ◽  
LING LI ◽  
JING WU ◽  
...  
Keyword(s):  
Finite Element ◽  
Intraocular Pressure ◽  
Element Model ◽  
Global Model ◽  
Eye Model ◽  
Human Eye ◽  
Anterior Eye Segment ◽  
Elevated Intraocular Pressure ◽  
Biomechanical Responses ◽  
Iop Elevation

Elevated intraocular pressure (IOP) may be the primary risk factor to the development of glaucoma. Finite element (FE) modeling is commonly considered as an effective method to quantitatively analyze pathogenesis of glaucoma. Recent researches focus on establishing partial human eye models. A refined global human eye model was developed using ANSYS software to investigate the correlation between IOP elevation and biomechanical responses. First, the pressure transferring process according to IOP elevation in the whole eye was analyzed to simulate the effects of IOP elevation on glaucoma. Then, the biomechanical responses of the anterior eye segment under various pressure differences between the anterior and posterior chambers (AC and PC) were analyzed to simulate posterior nonadhesion of iris and posterior synechia. This global eye model not only simulated the responses of elevated IOP on ocular structures, but also revealed the process of pressure transferring among each tissue from the anterior eye segment to the optic nerve head (ONH) region. The local mechanical characteristics of the ocular structures obtained from the global model agreed with previous findings. This global model may shed light on the studies of multifactorial glaucoma.

Microstructure Motivated Growth and Remodeling of the Lamina Cribrosa in Early Glaucoma

2011 ◽  
Author(s):  
Rafael Grytz ◽  
Ian A. Sigal ◽  
Jeffrey W. Ruberti ◽  
J. Crawford Downs
Keyword(s):  
Connective Tissue ◽  
Structural Changes ◽  
Lamina Cribrosa ◽  
Posterior Pole ◽  
Retinal Ganglion ◽  
Experimental Glaucoma ◽  
Relevant Risk Factor ◽  
Orbital Space ◽  
Iop Elevation ◽  
Pass Through

Glaucoma is a leading cause of blindness in the world and is due to the loss of retinal ganglion cell axons. These axons deteriorate in a region in the posterior pole of the eye known as the optic nerve head (ONH). The axons pass through the lamina cribrosa (LC) as they exit the eye at the ONH. The LC is characterized by a porous, connective tissue structure composed of laminar beams. The function of the LC is unclear, but is believed to include providing mechanical support to the axons as they transition from inside the pressurized globe to the lower pressure orbital space. Early experimental glaucoma studies have shown that the LC remodels into a thicker, more posterior structure which incorporates more connective tissue after chronic IOP elevation [1,2]. The process by which this occurs is unknown. These structural changes are assumed to play an important role in the pathophysiology of the ocular disease glaucoma, where elevated IOP is known to be the most relevant risk factor.

A Study on Application of the Honeycomb Structure in the Large-Scaled Parts

2010 ◽  
Vol 426-427 ◽  
pp. 525-528
Author(s):  
F.H. Yin ◽  
H. Guo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Strain Distribution ◽  
Large Scale ◽  
Honeycomb Structure ◽  
Theoretical Research ◽  
Stress And Strain ◽  
The Finite Element Method ◽  
Simulation Results ◽  
Stress And Strain Distribution

The Application of honeycomb structure was studied for the large-scaled structures in the paper. Stress and strain distribution of different nephogram structure is gained by the finite element method (FEM), the simulation results are discussed. Based on above-mentioned analysis, the evaluation of distortion is accomplished. The research provides a useful reference for the design of large-scale structure; it has had a certain project practical value and theoretical research value academically.

The Applicability Study on the Multi-Layer Shell Element Method in Steel Concrete Structure of Shield Building

2017 ◽  
Author(s):  
Wei Chao
Keyword(s):  
Finite Element ◽  
Concrete Structure ◽  
Large Scale ◽  
Shell Element ◽  
Stress And Strain ◽  
Commercial Aircraft ◽  
Integral Points ◽  
Finite Element Software ◽  
Equivalent Method ◽  
Element Method

In order to withstand the malicious impact of large commercial aircraft, the structure of steel concrete is usually used for shield building’s exterior wall, but due to the form of steel concrete structure is special, it often bring difficulties to the computational analysis of finite element in the design and review. The multi-layer shell element is an equivalent method based on the actual physical layering of material, and has the corresponding function in large-scale finite element software (ANSYS, ABAQUS). The method basic idea is to build a shell element based on the mechanics of composite material. According to the requirement, the shell element can be divided into different thicknesses, material properties and appropriate number of integral points. In the finite element calculation, the stress and strain values can be calculated independently for each integration point. This paper aiming the steel concrete structure in the checking calculation of shield building, used the multi-layer shell element method to simulate and analysis. Based on the modal analysis and spectrum analysis calculations of shield building are performed by using the finite element methods, studying the applicable condition of the methods. The analysis showed that the multi-layer shell element method are able to effectively simulate the structure of steel concrete, and can view more detailed analysis of the stress distribution of steel inside the concrete steel and concrete between the layers, in order to better grasp the safety of the shielding plant.

FEM Validation of a Spectral Viscoelastic Model of Posterior Sclera

2002 ◽  
Author(s):  
J. Crawford Downs ◽  
J.-K. Francis Suh ◽  
Claude F. Burgoyne ◽  
Richard T. Hart
Keyword(s):  
Finite Element ◽  
Intraocular Pressure ◽  
Material Properties ◽  
Viscoelastic Model ◽  
Element Model ◽  
Posterior Pole ◽  
Fem Validation ◽  
Mathematical And Computational Modeling

The eye is biomechanical pressure vessel, and mathematical and computational modeling of the posterior pole of the primate eye can be utilized to investigate the role of intraocular pressure (IOP) in the development and progression of glaucoma. The objective of this study is to validate an experimentally-derived, spectral viscoelastic characterization of scleral material properties utilizing a finite element model under cyclic loading.

Stochastic Modeling to Identify the Normal Response of an Optic Nerve Head to Small Increases in Intraocular Pressure

2011 ◽  
Author(s):  
Ian A. Sigal ◽  
Jonathan L. Grimm
Keyword(s):  
Intraocular Pressure ◽  
Optic Nerve ◽  
Optic Nerve Head ◽  
Statistical Power ◽  
Lamina Cribrosa ◽  
Small Subset ◽  
Retinal Ganglion ◽  
Main Risk Factor ◽  
Elevated Intraocular Pressure ◽  
Subsequent Loss

Glaucoma is one of the leading causes of blindness worldwide. Although elevated intraocular pressure (IOP) is the main risk factor for the development of the disease, its role remains unclear. Several studies have explored the hypothesis that an IOP-induced altered biomechanical environment within the optic nerve head (ONH), and the lamina cribrosa in particular, may contribute to disruption of the retinal ganglion cell axons, and the subsequent loss of vision associated with glaucoma [1–3]. Identifying the normal ONH biomechanical environment, however, has proven challenging. This has been in part because of the difficulty in accessing the ONH directly for experimentation, but also because of the difficulty in reconstructing models of the relevant structures with which to estimate its biomechanics. Few models represent only a small subset of the possible variations in ONH characteristics in a population, with the consequent lack of statistical power in the predictions.

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