title: Biomechanical aspects of axonal damage in glaucoma: A brief review.
abstract: The biomechanical environment within the optic nerve head (ONH) is complex and is likely directly involved in the loss of retinal ganglion cells (RGCs) in glaucoma. Unfortunately, our understanding of this process is poor. Here we describe factors that influence ONH biomechanics, including ONH connective tissue microarchitecture and anatomy; intraocular pressure (IOP); and cerebrospinal fluid pressure (CSFp). We note that connective tissue factors can vary significantly from one individual to the next, as well as regionally within an eye, and that the understanding of ONH biomechanics is hindered by anatomical differences between small-animal models of glaucoma (rats and mice) and humans. Other challenges of using animal models of glaucoma to study the role of biomechanics include the complexity of assessing the degree of glaucomatous progression; and inadequate tools for monitoring and consistently elevating IOP in animal models. We conclude with a consideration of important open research questions/challenges in this area, including: (i) Creating a systems biology description of the ONH; (ii) addressing the role of astrocyte connective tissue remodeling and reactivity in glaucoma; (iii) providing a better characterization of ONH astrocytes and non-astrocytic constituent cells; (iv) better understanding the role of ONH astrocyte phagocytosis, proliferation and death; (v) collecting gene expression and phenotype data on a larger, more coordinated scale; and (vi) developing an implantable IOP sensor.
authors.affiliation: Optic Nerve Head Research Laboratory, Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Health System, Portland, Oregon, USA.
authors.forename: Cheri
authors.initials: C
authors.lastname: Stowell
authors.affiliation: Optic Nerve Head Research Laboratory, Discoveries in Sight Research Laboratories, Devers Eye Institute, Legacy Health System, Portland, Oregon, USA.
authors.forename: Claude F
authors.initials: CF
authors.lastname: Burgoyne
authors.affiliation: Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany.
authors.forename: Ernst R
authors.initials: ER
authors.lastname: Tamm
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, GA, USA. Electronic address: ross.ethier@bme.gatech.edu.
authors.forename: C Ross
authors.initials: CR
authors.lastname: Ethier
mesh_terms: D000818:Animals; D001369:Axons / Q000473:pathology*; D001696:Biomechanical Phenomena / Q000502:physiology; D015170:Cerebrospinal Fluid Pressure / Q000502:physiology; D003238:Connective Tissue / Q000473:pathology; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D009898:Optic Disk / Q000503:physiopathology*; D009901:Optic Nerve Diseases / Q000503:physiopathology*; D012165:Retinal Ganglion Cells / Q000473:pathology*