Biomechanics of the Posterior Eye: A Critical Role in Health and Disease

Abstract

The posterior eye is a complex biomechanical structure. Delicate neural and vascular tissues of the retina, choroid, and optic nerve head that are critical for visual function are subjected to mechanical loading from intraocular pressure, intraocular and extraorbital muscles, and external forces on the eye. The surrounding sclera serves to counteract excessive deformation from these forces and thus to create a stable biomechanical environment for the ocular tissues. Additionally, the eye is a dynamic structure with connective tissue remodeling occurring as a result of aging and pathologies such as glaucoma and myopia. The material properties of these tissues and the distribution of stresses and strains in the posterior eye is an area of active research, relying on a combination of computational modeling, imaging, and biomechanical measurement approaches. Investigators are recognizing the increasing importance of the role of the collagen microstructure in these material properties and are undertaking microstructural measurements to drive microstructurally-informed models of ocular biomechanics. Here, we review notable findings and the consensus understanding on the biomechanics and microstructure of the posterior eye. Results from computational and numerical modeling studies and mechanical testing of ocular tissue are discussed. We conclude with some speculation as to future trends in this field.

High-Magnitude and/or High-Frequency Mechanical Strain Promotes Peripapillary Scleral Myofibroblast Differentiation

“…[1][2][3] The peripapillary sclera (ppSc) provides mechanical boundary conditions of the ONH at the neural canal and transmits biomechanical strain directly to the lamina cribrosa (LC) at its insertion into the scleral canal wall. Hence, the IOP-related biomechanical response of the ppSc plays a crucial role in the regulation of biomechanical response and environment of the ONH and LC.…”

Reduction of the Lamina Cribrosa Curvature After Trabeculectomy in Glaucoma

“…9 Lamina cribrosa bowing would in turn affect the axons passing through the laminar pores, [10][11][12] which may lead to direct axonal damage, or indirect damage through the interruption of the axoplasmic flow, alteration in the microcapillary blood flow, or activation of astrocytes, glial, and LC cells. 2,13,14 Accordingly, a proper characterization of ONH biomechanics in vivo may be a necessary step toward an improved understanding of glaucoma pathogenesis. 15,16 So far, parameters that are related to the biomechanics of the ONH and measurable in vivo have been limited.…”

Sekundärerkrankungen bei hoher Myopie

“…Somit könnte sich einer erhöhte Empfindlichkeit der temporalen Netzhaut erklären, die am Papillenrand meist nur noch aus einer dünnen Schicht von Nervenfasernbesteht [14]. Trotz der frühen Beschreibungen eines möglichen Zusammenhangs muss die große Achslänge als Risikofaktor des Offenwinkelglaukoms durchaus differenziert diskutiert werden [20,50,164].…”