title: Effects of Peripapillary Scleral Stiffening on the Deformation of the Lamina Cribrosa.
abstract: Scleral stiffening has been proposed as a treatment for glaucoma to protect the lamina cribrosa (LC) from excessive intraocular pressure-induced deformation. Here we experimentally evaluated the effects of moderate stiffening of the peripapillary sclera on the deformation of the LC.
  
  
  
  An annular sponge, saturated with 1.25% glutaraldehyde, was applied to the external surface of the peripapillary sclera for 5 minutes to stiffen the sclera. Tissue deformation was quantified in two groups of porcine eyes, using digital image correlation (DIC) or computed tomography imaging and digital volume correlation (DVC). In group A (n = 14), eyes were subjected to inflation testing before and after scleral stiffening. Digital image correlation was used to measure scleral deformation and quantify the magnitude of scleral stiffening. In group B (n = 5), the optic nerve head region was imaged using synchrotron radiation phase-contrast microcomputed tomography (PC μCT) at an isotropic spatial resolution of 3.2 μm. Digital volume correlation was used to compute the full-field three-dimensional deformation within the LC and evaluate the effects of peripapillary scleral cross-linking on LC biomechanics.
  
  
  
  On average, scleral treatment with glutaraldehyde caused a 34 ± 14% stiffening of the peripapillary sclera measured at 17 mm Hg and a 47 ± 12% decrease in the maximum tensile strain in the LC measured at 15 mm Hg. The reduction in LC strains was not due to cross-linking of the LC.
  
  
  
  Peripapillary scleral stiffening is effective at reducing the magnitude of biomechanical strains within the LC. Its potential and future utilization in glaucoma axonal neuroprotection requires further investigation.
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Coudrillier
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States 2Atlanta VA Medical Center, Decatur, Georgia, United States.
authors.forename: Ian C
authors.initials: IC
authors.lastname: Campbell
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States.
authors.forename: A Thomas
authors.initials: AT
authors.lastname: Read
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: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States.
authors.forename: Andrew
authors.initials: A
authors.lastname: Feola
authors.affiliation: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States.
authors.forename: John
authors.initials: J
authors.lastname: Mulvihill
authors.affiliation: Optic Nerve Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, United Kingdom 6Cardiff 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: Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States 2Atlanta VA Medical Center, Decatur, Georgia, United States.
authors.forename: C Ross
authors.initials: CR
authors.lastname: Ethier
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D004195:Disease Models, Animal; D005901:Glaucoma / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D007429:Intraocular Pressure / Q000502:physiology*; D008954:Models, Biological; D009898:Optic Disk / Q000473:pathology*; D009901:Optic Nerve Diseases / Q000175:diagnosis / Q000503:physiopathology*; D012590:Sclera / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013552:Swine; D055114:X-Ray Microtomography