title: Phase-Contrast Micro-Computed Tomography Measurements of the Intraocular Pressure-Induced Deformation of the Porcine Lamina Cribrosa.
abstract: The lamina cribrosa (LC) is a complex mesh-like tissue in the posterior eye. Its biomechanical environment is thought to play a major role in glaucoma, the second most common cause of blindness. Due to its small size and relative inaccessibility, high-resolution measurements of LC deformation, important in characterizing LC biomechanics, are challenging. Here we present a novel noninvasive imaging method, which enables measurement of the three-dimensional deformation of the LC caused by acute elevation of intraocular pressure (IOP). Posterior segments of porcine eyes were imaged using synchrotron radiation phase contrast micro-computed tomography (PC μCT) at IOPs between 6 and 37 mmHg. The complex trabecular architecture of the LC was reconstructed with an isotropic spatial resolution of 3.2 μm. Scans acquired at different IOPs were analyzed with digital volume correlation (DVC) to compute full-field deformation within the LC. IOP elevation caused substantial tensile, shearing and compressive devformation within the LC, with maximum tensile strains at 30 mmHg averaging 5.5%, and compressive strains reaching 20%. We conclude that PC μCT provides a novel high-resolution method for imaging the LC, and when combined with DVC, allows for full-field 3D measurement of ex vivo LC biomechanics at high spatial resolution.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Coudrillier
authors.forename: Diogo M
authors.initials: DM
authors.lastname: Geraldes
authors.forename: Nghia T
authors.initials: NT
authors.lastname: Vo
authors.forename: Robert
authors.initials: R
authors.lastname: Atwood
authors.forename: Christina
authors.initials: C
authors.lastname: Reinhard
authors.forename: Ian C
authors.initials: IC
authors.lastname: Campbell
authors.forename: Yazdan
authors.initials: Y
authors.lastname: Raji
authors.forename: Julie
authors.initials: J
authors.lastname: Albon
authors.forename: Richard L
authors.initials: RL
authors.lastname: Abel
authors.forename: C Ross
authors.initials: CR
authors.lastname: Ethier
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D005123:Eye / Q000000981:diagnostic imaging / Q000503:physiopathology; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007429:Intraocular Pressure / Q000502:physiology*; D013552:Swine; D055114:X-Ray Microtomography / Q000379:methods*