Changes in the Biomechanical Response of the Optic Nerve Head in Early Experimental Glaucoma
Open Access
- 1 November 2010
- journal article
- glaucoma
- Published by Association for Research in Vision and Ophthalmology (ARVO) in Investigative Opthalmology & Visual Science
- Vol. 51 (11), 5675-5684
- https://doi.org/10.1167/iovs.10-5411
Abstract
Purpose.: To investigate the biomechanical response of the optic nerve head (ONH) connective tissues to IOP elevation in three pairs of monkey eyes in which one eye had early experimental glaucoma (EG). Methods.: A serial imaging technique was used to reconstruct the ONH and peripapillary sclera of three pairs of unilateral EG eyes fixed at 10 mm Hg. Eye-specific finite element models of the posterior pole were constructed with inhomogeneous material properties defined for the lamina cribrosa (LC) based on local connective tissue volume fraction (CTVF) and predominant LC beam orientation. These models were used to simulate an IOP increase from 10 to 45 mm Hg. A laminar material constant was varied to produce a range of LC displacements and scleral canal expansions, and the associated LC stress and strain were characterized. Results.: The models suggest that the LC of normal and EG eyes can deform posteriorly or anteriorly when the LC material stiffness is low or high, respectively. Scleral canal expansion was generally, but not always, reduced in EG eyes. Strains in the EG eye were similar to or lower than those in the contralateral eye for the same average LC displacement and increased when the LC was more pliant. Laminar stresses were consistently lower in the EG eye, regardless of LC stiffness. Conclusions.: Connective tissue remodeling in EG alters the biomechanical response of the LC to IOP elevation in an eye-specific manner. The models indicated that the LC tissues in EG eyes were more plaint than those in the contralateral normal eyes in two of three monkeys.Keywords
This publication has 41 references indexed in Scilit:
- Correlation between Local Stress and Strain and Lamina Cribrosa Connective Tissue Volume Fraction in Normal Monkey EyesInvestigative Opthalmology & Visual Science, 2010
- Effect of Cyclical Mechanical Stretch and Exogenous Transforming Growth Factor-??1 on Matrix Metalloproteinase-2 Activity in Lamina Cribrosa Cells from the Human Optic Nerve HeadJournal of Glaucoma, 2004
- Factors that predict the benefit of lowering intraocular pressure in normal tension glaucomaAmerican Journal of Ophthalmology, 2003
- Viscoelastic Characterization of Peripapillary Sclera: Material Properties by Quadrant in Rabbit and Monkey EyesJournal of Biomechanical Engineering, 2003
- Factors for Glaucoma Progression and the Effect of TreatmentAmerican Journal of Ophthalmology, 2003
- Peripapillary scleral thickness in perfusion-fixed normal monkey eyes.2002
- The Ocular Hypertension Treatment StudyAmerican Journal of Ophthalmology, 2002
- Posterior scleral thickness in perfusion-fixed normal and early-glaucoma monkey eyes.2001
- Stress, Strain, and Mechanotransduction in CellsJournal of Biomechanical Engineering, 2001
- The optic nerve head in glaucoma: role of astrocytes in tissue remodelingProgress in Retinal and Eye Research, 2000