| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1From the Department of Mechanical and Industrial Engineering, the 2Institute for Biomaterials and Biomedical Engineering, and the 3Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada; and the 4School of Optometry, University of Waterloo, Waterloo, Canada.
PURPOSE. The biomechanical environment within the optic nerve head (ONH) may play a role in retinal ganglion cell loss in glaucomatous optic neuropathy. This was a systematic analysis in which finite element methods were used to determine which anatomic and biomechanical factors most influenced the biomechanical response of the ONH to acute changes in IOP.
METHODS. Based on a previously described computational model of the eye, each of 21 input factors, representing the biomechanical properties of relevant ocular tissues, the IOP, and 14 geometric factors were independently varied. The biomechanical response of the ONH tissues was quantified through a set of 29 outcome measures, including peak and mean stress and strain within each tissue, and measures of geometric changes in ONH tissues. Input factors were ranked according to their aggregated influence on groups of outcome measures.
RESULTS. The five input factors that had the largest influence across all outcome measures were, in ranked order: stiffness of the sclera, radius of the eye, stiffness of the lamina cribrosa, IOP, and thickness of the scleral shell. The five least influential factors were, in reverse ranked order: retinal thickness, peripapillary rim height, cup depth, cup-to-disc ratio, and pial thickness. Factor ranks were similar for various outcome measure groups and factor ranges.
CONCLUSIONS. The model predicts that ONH biomechanics are strongly dependent on scleral biomechanical properties. Acute deformations of ONH tissues, and the consequent high levels of neural tissue strain, were less strongly dependent on the action of IOP directly on the internal surface of the ONH than on the indirect effects of IOP on the sclera. This suggests that interindividual variations in scleral properties could be a risk factor for the development of glaucoma. Eye size and lamina cribrosa biomechanical properties also have a strong influence on ONH biomechanics.
This article has been cited by other articles:
|
|
 |
|
  M. D. Roberts, Y. Liang, I. A. Sigal, J. Grimm, J. Reynaud, A. Bellezza, C. F. Burgoyne, and J. C. Downs Correlation between Local Stress and Strain and Lamina Cribrosa Connective Tissue Volume Fraction in Normal Monkey Eyes Invest. Ophthalmol. Vis. Sci., January 1, 2010; 51(1): 295 - 307. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Kakutani, M. Nakamura, A. Nagai-Kusuhara, A. Kanamori, and A. Negi Marked Cup Reversal Presumably Associated With Scleral Biomechanics in a Case of Adult Glaucoma Arch Ophthalmol, January 1, 2010; 128(1): 139 - 141. [Full Text] [PDF]
|
|
|
|
|
|
H. Yang, J. C. Downs, I. A. Sigal, M. D. Roberts, H. Thompson, and C. F. Burgoyne Deformation of the Normal Monkey Optic Nerve Head Connective Tissue after Acute IOP Elevation within 3-D Histomorphometric Reconstructions Invest. Ophthalmol. Vis. Sci., December 1, 2009; 50(12): 5785 - 5799. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. J. A. Girard, J.-K. F. Suh, M. Bottlang, C. F. Burgoyne, and J. C. Downs Scleral Biomechanics in the Aging Monkey Eye Invest. Ophthalmol. Vis. Sci., November 1, 2009; 50(11): 5226 - 5237. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Amini and V. H. Barocas Anterior Chamber Angle Opening during Corneoscleral Indentation: The Mechanism of Whole Eye Globe Deformation and the Importance of the Limbus Invest. Ophthalmol. Vis. Sci., November 1, 2009; 50(11): 5288 - 5294. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. R. Band, C. L. Hall, G. Richardson, O. E. Jensen, J. H. Siggers, and A. J. E. Foss Intracellular Flow in Optic Nerve Axons: A Mechanism for Cell Death in Glaucoma Invest. Ophthalmol. Vis. Sci., August 1, 2009; 50(8): 3750 - 3758. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. A. Sigal Interactions between Geometry and Mechanical Properties on the Optic Nerve Head Invest. Ophthalmol. Vis. Sci., June 1, 2009; 50(6): 2785 - 2795. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Ren, N. Wang, B. Li, L. Li, F. Gao, X. Xu, and J. B. Jonas Lamina Cribrosa and Peripapillary Sclera Histomorphometry in Normal and Advanced Glaucomatous Chinese Eyes with Various Axial Length Invest. Ophthalmol. Vis. Sci., May 1, 2009; 50(5): 2175 - 2184. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Liu and X. He Corneal Stiffness Affects IOP Elevation during Rapid Volume Change in the Eye Invest. Ophthalmol. Vis. Sci., May 1, 2009; 50(5): 2224 - 2229. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
I. L. Thornton, W. J. Dupps, A. S. Roy, and R. R. Krueger Biomechanical Effects of Intraocular Pressure Elevation on Optic Nerve/Lamina Cribrosa before and after Peripapillary Scleral Collagen Cross-Linking Invest. Ophthalmol. Vis. Sci., March 1, 2009; 50(3): 1227 - 1233. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Yang, J. C. Downs, and C. F. Burgoyne Physiologic Intereye Differences in Monkey Optic Nerve Head Architecture and Their Relation to Changes in Early Experimental Glaucoma Invest. Ophthalmol. Vis. Sci., January 1, 2009; 50(1): 224 - 234. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Hommer, G. Fuchsjager-Mayrl, H. Resch, C. Vass, G. Garhofer, and L. Schmetterer Estimation of Ocular Rigidity Based on Measurement of Pulse Amplitude Using Pneumotonometry and Fundus Pulse Using Laser Interferometry in Glaucoma Invest. Ophthalmol. Vis. Sci., September 1, 2008; 49(9): 4046 - 4050. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. P. Wells, D. F. Garway-Heath, A. Poostchi, T. Wong, K. C. Y. Chan, and N. Sachdev Corneal Hysteresis but Not Corneal Thickness Correlates with Optic Nerve Surface Compliance in Glaucoma Patients Invest. Ophthalmol. Vis. Sci., August 1, 2008; 49(8): 3262 - 3268. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Yang, J. C. Downs, C. Girkin, L. Sakata, A. Bellezza, H. Thompson, and C. F. Burgoyne 3-D Histomorphometry of the Normal and Early Glaucomatous Monkey Optic Nerve Head: Lamina Cribrosa and Peripapillary Scleral Position and Thickness Invest. Ophthalmol. Vis. Sci., October 1, 2007; 48(10): 4597 - 4607. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Balaratnasingam, W. H. Morgan, L. Bass, G. Matich, S. J. Cringle, and D.-Y. Yu Axonal Transport and Cytoskeletal Changes in the Laminar Regions after Elevated Intraocular Pressure Invest. Ophthalmol. Vis. Sci., August 1, 2007; 48(8): 3632 - 3644. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Downs, H. Yang, C. Girkin, L. Sakata, A. Bellezza, H. Thompson, and C. F. Burgoyne Three-Dimensional Histomorphometry of the Normal and Early Glaucomatous Monkey Optic Nerve Head: Neural Canal and Subarachnoid Space Architecture Invest. Ophthalmol. Vis. Sci., July 1, 2007; 48(7): 3195 - 3208. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 B K Pierscionek, M Asejczyk-Widlicka, and R A Schachar The effect of changing intraocular pressure on the corneal and scleral curvatures in the fresh porcine eye Br J Ophthalmol, June 1, 2007; 91(6): 801 - 803. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R A Schachar, A Abolmaali, and T Le Insights into the age-related decline in the amplitude of accommodation of the human lens using a non-linear finite-element model Br J Ophthalmol, October 1, 2006; 90(10): 1304 - 1309. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
