title: Deformation of the Lamina Cribrosa and Optic Nerve Due to Changes in Cerebrospinal Fluid Pressure.
abstract: Cerebrospinal fluid pressure (CSFp) changes are involved or implicated in various ocular conditions including glaucoma, idiopathic intracranial hypertension, and visual impairment and intracranial pressure syndrome. However, little is known about the effects of CSFp on lamina cribrosa and retrolaminar neural tissue (RLNT) biomechanics, potentially important in these conditions. Our goal was to use an experimental approach to visualize and quantify the deformation of these tissues as CSFp increased.
  
  
  
  The posterior eye and RLNT of porcine eyes (n = 3) were imaged using synchrotron radiation phase-contrast micro-computed tomography (PC μCT) at an intraocular pressure of 15 mm Hg and CSFps of 4, 10, 20, and 30 mm Hg. Scans of each tissue region were acquired at each CSFp step and analyzed using digital volume correlation to determine 3-dimensional tissue deformations.
  
  
  
  Elevating CSFp increased the strain in the lamina cribrosa and RLNT of all three specimens, with the largest strains occurring in the RLNT. Relative to the baseline CSFp of 4 mm Hg, at 30 mm Hg, the lamina cribrosa experienced a mean first and third principal strain of 4.4% and -3.5%, respectively. The corresponding values for the RLNT were 9.5% and -9.1%.
  
  
  
  CSFp has a significant impact on the strain distributions within the lamina cribrosa and, more prominently, within the RLNT. Elevations in CSFp were positively correlated with increasing deformations in each region and may play a role in ocular pathologies linked to changes in CSFp.
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Feola
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States 2Exponent, Inc., Menlo Park, California, United States.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Coudrillier
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States 3School of Engineering/Bernal Institute, University of Limerick, Limerick, Ireland.
authors.forename: John
authors.initials: J
authors.lastname: Mulvihill
authors.affiliation: Biomechanics Group, Department of Mechanical Engineering, Imperial College London, London, United Kingdom.
authors.forename: Diogo M
authors.initials: DM
authors.lastname: Geraldes
authors.affiliation: Diamond Light Source, Didcot, United Kingdom.
authors.forename: Nghia T
authors.initials: NT
authors.lastname: Vo
authors.affiliation: Optic Nerve Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom 7Cardiff Institute of Tissue Engineering and Repair, Cardiff University, Cardiff, Wales, United Kingdom.
authors.forename: Julie
authors.initials: J
authors.lastname: Albon
authors.affiliation: Department of Surgery and Cancer, Imperial College, London, United Kingdom.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Abel
authors.affiliation: Department of Ophthalmology, University of Alabama at Birmingham, Birmingham, Alabama, United States.
authors.forename: Brian C
authors.initials: BC
authors.lastname: Samuels
authors.affiliation: Department of Biomedical Engineering, Georgia Institute of Technology/Emory University, Atlanta, Georgia, United States.
authors.forename: C Ross
authors.initials: CR
authors.lastname: Ethier
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D015170:Cerebrospinal Fluid Pressure / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D005901:Glaucoma / Q000473:pathology / Q000503:physiopathology*; D007429:Intraocular Pressure; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology* / Q000503:physiopathology; D009900:Optic Nerve / Q000473:pathology*; D013552:Swine; D014065:Tonometry, Ocular; D055114:X-Ray Microtomography