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We propose here a conceptual framework for understanding the optic nerve head (ONH) as a biomechanical structure. Basic principles of biomechanical engineering are used to propose a central role for intraocular pressure (IOP)-related stress and strain in the physiology of ONH aging and the pathophysiology of glaucomatous damage. Our paradigm suggests that(More)
PURPOSE To delineate three-dimensionally the anterior and posterior surfaces of the lamina cribrosa, scleral flange, and peripapillary sclera, to determine the position and thickness of these structures within digital three-dimensional (3-D) reconstructions of the monkey optic nerve head (ONH). METHODS The trephinated ONH and peripapillary sclera from(More)
PURPOSE To delineate three dimensionally the neural canal landmarks-Bruch's membrane opening (BMO), anterior sclera canal opening (ASCO), anterior laminar insertion (ALI), posterior laminar insertion (PLI), and posterior scleral canal opening (PSCO)-and the anterior-most aspect of the subarachnoid space (ASAS), within digital three-dimensional (3-D)(More)
PURPOSE To characterize scleral biomechanics in both eyes of eight monkeys in which chronic intraocular pressure (IOP) elevation was induced in one eye. METHODS Each posterior sclera was mounted on a pressurization apparatus, IOP was elevated from 5 to 45 mm Hg while the 3D displacements of the scleral surface were measured by speckle interferometry.(More)
PURPOSE To introduce a three-dimensional (3-D) histomorphometric strategy for characterizing the connective tissue (laminar) and prelaminar neural tissue (prelaminar) components of optic nerve head (ONH) cupping in one bilaterally normal monkey and three monkeys with early experimental glaucoma (EG) in one eye. METHODS Trephined ONH and peripapillary(More)
Glaucoma is a blinding diseases in which damage to the axons results in loss of retinal ganglion cells. Experimental evidence indicates that chronic intraocular pressure elevation initiates axonal insult at the level of the lamina cribrosa. The lamina cribrosa is a porous collagen structure through which the axons pass on their path from the retina to the(More)
PURPOSE To test the hypothesis that pathophysiologic deformation of the lamina cribrosa and anterior scleral canal wall underlies the onset of confocal scanning laser tomography (CSLT)-detected optic nerve head (ONH) surface change in early experimental glaucoma. METHODS Both eyes of four normal (two normal eyes) monkeys and four with early glaucoma (one(More)
PURPOSE To investigate the age-related differences in the inhomogeneous, anisotropic, nonlinear biomechanical properties of posterior sclera from old (22.9 +/- 5.3 years) and young (1.5 +/- 0.7 years) rhesus monkeys. METHODS The posterior scleral shell of each eye was mounted on a custom-built pressurization apparatus, then intraocular pressure (IOP) was(More)
PURPOSE To test the hypothesis that changes in the viscoelastic material properties of peripapillary sclera are present within monkey eyes at the onset of early experimental glaucoma detected by confocal scanning laser tomography (CSLT). METHODS Short-term (3-9 weeks), moderate (< or =44 mm Hg) intraocular pressure (IOP) elevation was induced in one eye(More)
PURPOSE To characterize optic nerve head (ONH) connective tissue deformation after acute (15 or 30 minutes) intraocular pressure (IOP) elevation in six adult normal monkeys using three-dimensional (3-D) histomorphometry. METHODS Trephined ONH and peripapillary sclera from both eyes of six monkeys, each perfusion fixed with one eye at IOP 10 mm Hg (IOP-10)(More)