Cheryl R Hann1, Andrew J Vercnocke2, Michael D Bentley3, Steven M Jorgensen2, Michael P Fautsch1. 1. Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States. 2. Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, United States. 3. Department of Biological Sciences, Minnesota State University, Mankato, Minnesota, United States.
Abstract
PURPOSE: To examine the anatomy of Schlemm's canal (SC) and collector channels (CCs) in normal human and primary open-angle glaucoma (POAG) eyes under low and high perfusion pressure. METHODS: In normal (n = 3) and POAG (n = 3) eye pairs, one eye was perfused at 10 mm Hg while the fellow eye was perfused at 20 mm Hg for 2 hours. Eyes were perfusion fixed at like pressures, dissected into quadrants, embedded in Epon Araldite, and scanned by three-dimensional micro-computed tomography (3D micro-CT). Schlemm's canal volume, CC orifice area, diameter, and number were measured using ANALYZE software. RESULTS: Normal eyes showed a larger SC volume (3.3-fold) and CC orifice area (9962.8 vs. 8825.2 μm(2)) and a similar CC diameter (34.3 ± 17.8 vs. 32.7 ± 13.0 μm) at 10 mm Hg compared to 20 mm Hg. In POAG eyes, SC volume (2.0-fold), CC orifice area (8049.2 μm(2)-6468.4 μm(2)), and CC diameter (36.2 ± 19.1 vs. 29.0 ± 13.8 μm) were increased in 10 mm Hg compared to 20 mm Hg perfusion pressures. Partial and total CC occlusions were present in normal and POAG eyes, with a 3.7-fold increase in total occlusions in POAG eyes compared to normal eyes at 20 mm Hg. Visualization of CCs increased by 24% in normal and by 21% in POAG eyes at 20 mm Hg compared to 10 mm Hg. Schlemm's canal volume, CC area, and CC diameter were decreased in POAG eyes compared to normal eyes at like pressures. CONCLUSIONS: Compensatory mechanisms for transient and short periods of increased pressure appear to be diminished in POAG eyes. Variable response to pressure change in SC and CCs may be a contributing factor to outflow facility change in POAG eyes. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.
PURPOSE: To examine the anatomy of Schlemm's canal (SC) and collector channels (CCs) in normal human and primary open-angle glaucoma (POAG) eyes under low and high perfusion pressure. METHODS: In normal (n = 3) and POAG (n = 3) eye pairs, one eye was perfused at 10 mm Hg while the fellow eye was perfused at 20 mm Hg for 2 hours. Eyes were perfusion fixed at like pressures, dissected into quadrants, embedded in Epon Araldite, and scanned by three-dimensional micro-computed tomography (3D micro-CT). Schlemm's canal volume, CC orifice area, diameter, and number were measured using ANALYZE software. RESULTS: Normal eyes showed a larger SC volume (3.3-fold) and CC orifice area (9962.8 vs. 8825.2 μm(2)) and a similar CC diameter (34.3 ± 17.8 vs. 32.7 ± 13.0 μm) at 10 mm Hg compared to 20 mm Hg. In POAG eyes, SC volume (2.0-fold), CC orifice area (8049.2 μm(2)-6468.4 μm(2)), and CC diameter (36.2 ± 19.1 vs. 29.0 ± 13.8 μm) were increased in 10 mm Hg compared to 20 mm Hg perfusion pressures. Partial and total CC occlusions were present in normal and POAG eyes, with a 3.7-fold increase in total occlusions in POAG eyes compared to normal eyes at 20 mm Hg. Visualization of CCs increased by 24% in normal and by 21% in POAG eyes at 20 mm Hg compared to 10 mm Hg. Schlemm's canal volume, CC area, and CC diameter were decreased in POAG eyes compared to normal eyes at like pressures. CONCLUSIONS: Compensatory mechanisms for transient and short periods of increased pressure appear to be diminished in POAG eyes. Variable response to pressure change in SC and CCs may be a contributing factor to outflow facility change in POAG eyes. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.
Authors: Stephanie A Battista; Zhaozeng Lu; Sara Hofmann; Thomas Freddo; Darryl R Overby; Haiyan Gong Journal: Invest Ophthalmol Vis Sci Date: 2008-05-30 Impact factor: 4.799
Authors: Larry Kagemann; Gadi Wollstein; Hiroshi Ishikawa; Richard A Bilonick; Peter M Brennen; Lindsey S Folio; Michelle L Gabriele; Joel S Schuman Journal: Invest Ophthalmol Vis Sci Date: 2010-03-17 Impact factor: 4.799
Authors: Alex S Huang; Akram Belghith; Anna Dastiridou; Vikas Chopra; Linda M Zangwill; Robert N Weinreb Journal: J Biomed Opt Date: 2017-06-01 Impact factor: 3.170
Authors: Alex S Huang; Rafaella C Penteado; Sajib K Saha; Jiun L Do; Philip Ngai; Zhihong Hu; Robert N Weinreb Journal: J Glaucoma Date: 2018-11 Impact factor: 2.503
Authors: Cula N Dautriche; Dennis Szymanski; Matthew Kerr; Karen Y Torrejon; Magnus Bergkvist; Yubing Xie; John Danias; W D Stamer; Susan T Sharfstein Journal: Biomaterials Date: 2015-06-20 Impact factor: 12.479
Authors: Jingwen Cai; Kristin M Perkumas; Xuejun Qin; Michael A Hauser; W Daniel Stamer; Yutao Liu Journal: Invest Ophthalmol Vis Sci Date: 2015-10 Impact factor: 4.799
Authors: W Daniel Stamer; Sietse T Braakman; Enhua H Zhou; C Ross Ethier; Jeffrey J Fredberg; Darryl R Overby; Mark Johnson Journal: Prog Retin Eye Res Date: 2014-09-16 Impact factor: 21.198