Mary Rebecca Telle1, Kevin C Snyder1,2, Kazuya Oikawa1,2, Jacob P Nilles1, Shaile Gehrke1, Leandro B C Teixeira3, Julie A Kiland2, Alex Huang4, Gillian J McLellan1,2. 1. Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA. 2. Department of Ophthalmology & Visual Sciences, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, USA. 3. Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA. 4. Shiley Eye Institute, The Viterbi Family Department of Ophthalmology, University of California, San Diego, California, USA.
Abstract
PURPOSE: Angle closure glaucoma (PACG) is highly prevalent in dogs and is often refractory to medical therapy. We hypothesized that pathology affecting the post-trabecular conventional aqueous outflow pathway contributes to persistent intraocular pressure (IOP) elevation in dogs with PACG. The goal of this study was to determine the potential for aqueous angiography (AA) and optical coherence tomography (OCT) to identify abnormalities in post-trabecular aqueous outflow pathways in canine PACG. METHODS: AA and anterior segment OCT (Spectralis HRA + OCT) were performed ex vivo in 19 enucleated canine eyes (10 normal eyes and 9 irreversibly blind eyes from canine patients enucleated for management of refractory PACG). Eyes were cannulated and maintained at physiologic IOP (10-20 mmHg) prior to intracameral infusion of fluorescent tracer. OCT scleral line scans were acquired in regions of high and low perilimbal AA signal. Eyes were then perfusion fixed and cryosections prepared from 10/10 normal and 7/9 PACG eyes and immunolabeled for a vascular endothelial marker. RESULTS: Normal canine eyes showed segmental, circumferential limbal AA signal, whereas PACG eyes showed minimal or no AA signal. AA signal correlated with scleral lumens on OCT in normal dogs, but lumens were generally absent or flattened in PACG eyes. Collapsed vascular profiles were identified in tissue sections from PACG eyes, including those in which no lumens were identified on AA and OCT. CONCLUSIONS: In canine eyes with PACG, distal aqueous outflow channels are not identifiable by AA, despite normalization of their IOP, and intra-scleral vascular profiles are collapsed on OCT and histopathology.
PURPOSE: Angle closure glaucoma (PACG) is highly prevalent in dogs and is often refractory to medical therapy. We hypothesized that pathology affecting the post-trabecular conventional aqueous outflow pathway contributes to persistent intraocular pressure (IOP) elevation in dogs with PACG. The goal of this study was to determine the potential for aqueous angiography (AA) and optical coherence tomography (OCT) to identify abnormalities in post-trabecular aqueous outflow pathways in canine PACG. METHODS: AA and anterior segment OCT (Spectralis HRA + OCT) were performed ex vivo in 19 enucleated canine eyes (10 normal eyes and 9 irreversibly blind eyes from canine patients enucleated for management of refractory PACG). Eyes were cannulated and maintained at physiologic IOP (10-20 mmHg) prior to intracameral infusion of fluorescent tracer. OCT scleral line scans were acquired in regions of high and low perilimbal AA signal. Eyes were then perfusion fixed and cryosections prepared from 10/10 normal and 7/9 PACG eyes and immunolabeled for a vascular endothelial marker. RESULTS: Normal canine eyes showed segmental, circumferential limbal AA signal, whereas PACG eyes showed minimal or no AA signal. AA signal correlated with scleral lumens on OCT in normal dogs, but lumens were generally absent or flattened in PACG eyes. Collapsed vascular profiles were identified in tissue sections from PACG eyes, including those in which no lumens were identified on AA and OCT. CONCLUSIONS: In canine eyes with PACG, distal aqueous outflow channels are not identifiable by AA, despite normalization of their IOP, and intra-scleral vascular profiles are collapsed on OCT and histopathology.
Authors: Bruce E Prum; Lisa F Rosenberg; Steven J Gedde; Steven L Mansberger; Joshua D Stein; Sayoko E Moroi; Leon W Herndon; Michele C Lim; Ruth D Williams Journal: Ophthalmology Date: 2015-11-12 Impact factor: 12.079
Authors: Alex S Huang; Sindhu Saraswathy; Anna Dastiridou; Alan Begian; Chirayu Mohindroo; James C H Tan; Brian A Francis; David R Hinton; Robert N Weinreb Journal: Invest Ophthalmol Vis Sci Date: 2016-09-01 Impact factor: 4.799
Authors: Alex S Huang; Sindhu Saraswathy; Anna Dastiridou; Alan Begian; Hanz Legaspi; Chirayu Mohindroo; James C H Tan; Brian A Francis; Joseph Caprioli; David R Hinton; Robert N Weinreb Journal: Transl Vis Sci Technol Date: 2016-11-10 Impact factor: 3.283
Authors: Kevin C Snyder; Kazuya Oikawa; Jeremy Williams; Julie A Kiland; Shaile Gehrke; Leandro B C Teixeira; Alex S Huang; Gillian J McLellan Journal: Transl Vis Sci Technol Date: 2019-10-09 Impact factor: 3.283