Numerical study of the effect of corneal layered structure on ocular biomechanics

Ahmed Elsheikh, Stuart Ross, Daad Alhasso, Paolo Rama

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Purpose: The study aimed to improve the accuracy of corneal numerical simulation by adopting a better representation of the corneal layered structure. The study considered both the shear and tensile behavior of the interface surfaces between stromal lamellae, and assessed the effect of modeling the cornea's three main layers - the epithelium, stroma, and endothelium with their respective material properties. Methods: Twelve human donor corneas were tested to determine the behavior of the stroma under surface shear. Numerical models were then built to consider the stromal inter-lamellar adhesion, which included the shear behavior determined experimentally and the tensile behavior available in the literature. They also adopted the distinctive material properties of the epithelium, stroma, and endothelium. The numerical models simulated corneal behavior under intraocular pressure elevation, concentric anterior pressure, and the conditions under tonometry with the Goldmann applanation tonometer. Results: The stress-strain shear behavior of stromal tissue followed an exponential pattern, with an initial low stiffness increasing gradually under higher stresses. This behavior was adopted in the numerical simulation to set the level of adhesion between stromal layers. Considering that the stromal inter-lamellar adhesion and the distinctive material properties of corneal layers had a significant effect in simulating the response to concentrated anterior pressures, which cause bending of corneal tissue, this was almost unnecessary when predicting the effect of intraocular pressure, which put the cornea under membrane tension. Conclusions: The corneal layered structure affects the results of numerical simulations especially in problems where the cornea is subjected to bending effects.

Original languageEnglish
Pages (from-to)26-35
Number of pages10
JournalCurrent Eye Research
Volume34
Issue number1
DOIs
Publication statusPublished - Jan 2009

Fingerprint

Biomechanical Phenomena
Cornea
Intraocular Pressure
Endothelium
Epithelium
Pressure
Manometry
Membranes

Keywords

  • Corneal biomechanics
  • Corneal microstructure
  • Numerical modeling

ASJC Scopus subject areas

  • Ophthalmology
  • Cellular and Molecular Neuroscience
  • Sensory Systems

Cite this

Numerical study of the effect of corneal layered structure on ocular biomechanics. / Elsheikh, Ahmed; Ross, Stuart; Alhasso, Daad; Rama, Paolo.

In: Current Eye Research, Vol. 34, No. 1, 01.2009, p. 26-35.

Research output: Contribution to journalArticle

Elsheikh, Ahmed ; Ross, Stuart ; Alhasso, Daad ; Rama, Paolo. / Numerical study of the effect of corneal layered structure on ocular biomechanics. In: Current Eye Research. 2009 ; Vol. 34, No. 1. pp. 26-35.
@article{f2fc4df13da444c3906de81fade05bd5,
title = "Numerical study of the effect of corneal layered structure on ocular biomechanics",
abstract = "Purpose: The study aimed to improve the accuracy of corneal numerical simulation by adopting a better representation of the corneal layered structure. The study considered both the shear and tensile behavior of the interface surfaces between stromal lamellae, and assessed the effect of modeling the cornea's three main layers - the epithelium, stroma, and endothelium with their respective material properties. Methods: Twelve human donor corneas were tested to determine the behavior of the stroma under surface shear. Numerical models were then built to consider the stromal inter-lamellar adhesion, which included the shear behavior determined experimentally and the tensile behavior available in the literature. They also adopted the distinctive material properties of the epithelium, stroma, and endothelium. The numerical models simulated corneal behavior under intraocular pressure elevation, concentric anterior pressure, and the conditions under tonometry with the Goldmann applanation tonometer. Results: The stress-strain shear behavior of stromal tissue followed an exponential pattern, with an initial low stiffness increasing gradually under higher stresses. This behavior was adopted in the numerical simulation to set the level of adhesion between stromal layers. Considering that the stromal inter-lamellar adhesion and the distinctive material properties of corneal layers had a significant effect in simulating the response to concentrated anterior pressures, which cause bending of corneal tissue, this was almost unnecessary when predicting the effect of intraocular pressure, which put the cornea under membrane tension. Conclusions: The corneal layered structure affects the results of numerical simulations especially in problems where the cornea is subjected to bending effects.",
keywords = "Corneal biomechanics, Corneal microstructure, Numerical modeling",
author = "Ahmed Elsheikh and Stuart Ross and Daad Alhasso and Paolo Rama",
year = "2009",
month = "1",
doi = "10.1080/02713680802535263",
language = "English",
volume = "34",
pages = "26--35",
journal = "Current Eye Research",
issn = "0271-3683",
publisher = "Informa Healthcare",
number = "1",

}

TY - JOUR

T1 - Numerical study of the effect of corneal layered structure on ocular biomechanics

AU - Elsheikh, Ahmed

AU - Ross, Stuart

AU - Alhasso, Daad

AU - Rama, Paolo

PY - 2009/1

Y1 - 2009/1

N2 - Purpose: The study aimed to improve the accuracy of corneal numerical simulation by adopting a better representation of the corneal layered structure. The study considered both the shear and tensile behavior of the interface surfaces between stromal lamellae, and assessed the effect of modeling the cornea's three main layers - the epithelium, stroma, and endothelium with their respective material properties. Methods: Twelve human donor corneas were tested to determine the behavior of the stroma under surface shear. Numerical models were then built to consider the stromal inter-lamellar adhesion, which included the shear behavior determined experimentally and the tensile behavior available in the literature. They also adopted the distinctive material properties of the epithelium, stroma, and endothelium. The numerical models simulated corneal behavior under intraocular pressure elevation, concentric anterior pressure, and the conditions under tonometry with the Goldmann applanation tonometer. Results: The stress-strain shear behavior of stromal tissue followed an exponential pattern, with an initial low stiffness increasing gradually under higher stresses. This behavior was adopted in the numerical simulation to set the level of adhesion between stromal layers. Considering that the stromal inter-lamellar adhesion and the distinctive material properties of corneal layers had a significant effect in simulating the response to concentrated anterior pressures, which cause bending of corneal tissue, this was almost unnecessary when predicting the effect of intraocular pressure, which put the cornea under membrane tension. Conclusions: The corneal layered structure affects the results of numerical simulations especially in problems where the cornea is subjected to bending effects.

AB - Purpose: The study aimed to improve the accuracy of corneal numerical simulation by adopting a better representation of the corneal layered structure. The study considered both the shear and tensile behavior of the interface surfaces between stromal lamellae, and assessed the effect of modeling the cornea's three main layers - the epithelium, stroma, and endothelium with their respective material properties. Methods: Twelve human donor corneas were tested to determine the behavior of the stroma under surface shear. Numerical models were then built to consider the stromal inter-lamellar adhesion, which included the shear behavior determined experimentally and the tensile behavior available in the literature. They also adopted the distinctive material properties of the epithelium, stroma, and endothelium. The numerical models simulated corneal behavior under intraocular pressure elevation, concentric anterior pressure, and the conditions under tonometry with the Goldmann applanation tonometer. Results: The stress-strain shear behavior of stromal tissue followed an exponential pattern, with an initial low stiffness increasing gradually under higher stresses. This behavior was adopted in the numerical simulation to set the level of adhesion between stromal layers. Considering that the stromal inter-lamellar adhesion and the distinctive material properties of corneal layers had a significant effect in simulating the response to concentrated anterior pressures, which cause bending of corneal tissue, this was almost unnecessary when predicting the effect of intraocular pressure, which put the cornea under membrane tension. Conclusions: The corneal layered structure affects the results of numerical simulations especially in problems where the cornea is subjected to bending effects.

KW - Corneal biomechanics

KW - Corneal microstructure

KW - Numerical modeling

UR - http://www.scopus.com/inward/record.url?scp=59449089967&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=59449089967&partnerID=8YFLogxK

U2 - 10.1080/02713680802535263

DO - 10.1080/02713680802535263

M3 - Article

C2 - 19172467

AN - SCOPUS:59449089967

VL - 34

SP - 26

EP - 35

JO - Current Eye Research

JF - Current Eye Research

SN - 0271-3683

IS - 1

ER -