title: The role of retrobulbar and retinal circulation on optic nerve head and retinal nerve fibre layer structure in patients with open-angle glaucoma over an 18-month period.
abstract: OBJECTIVE
  Evidence suggests that vascular abnormalities play a role in the pathogenesis of open-angle glaucoma (OAG) in some patients. This study aims to assess changes in retrobulbar and retinal blood flow over time in patients with glaucoma and examine their relationship to glaucomatous progression, as determined by retinal and optic nerve structure.
  
  
  METHODS
  In this observational study, 103 patients with OAG were examined at baseline and 18 months follow-up. Retrobulbar blood flow was measured by colour Doppler imaging in the ophthalmic, central retinal and temporal posterior ciliary artery (TPCA) and nasal short posterior ciliary artery. Retinal capillary blood flow was measured by confocal scanning laser Doppler. Peripapillary retinal nerve fibre layer thickness was assessed by optical coherence tomography. Non-parametric Wilcoxon signed ranks tests were used to assess for any statistically significant changes between the baseline and 18-month visits for the retrobulbar and retinal flow, as well as the structural parameters.
  
  
  RESULTS
  In general, retinal and retrobulbar blood flow parameters decreased over 18 months. Thinning of the optic disc rim and increase in cup area were associated with a higher resistance index (p=0.0334) and lower peak systolic velocity of TPCA (p=0.0282), respectively. A higher amount of retinal zero pixel blood flow correlated with a greater increase in cup/disc ratio (p=0.0170).
  
  
  CONCLUSIONS
  Reductions in retrobulbar and retinal blood flow over time were associated with structural glaucomatous progression, as indicated by retinal and optic nerve changes.
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Leslie Abrams
authors.initials: LA
authors.lastname: Tobe
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Alon
authors.initials: A
authors.lastname: Harris
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA.
authors.forename: Rehan M
authors.initials: RM
authors.lastname: Hussain
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: George
authors.initials: G
authors.lastname: Eckert
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Huck
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Joshua
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Patrick
authors.initials: P
authors.lastname: Egan
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Nathaniel J
authors.initials: NJ
authors.lastname: Kim
authors.affiliation: Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
authors.forename: Brent
authors.initials: B
authors.lastname: Siesky
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001775:Blood Circulation / Q000502:physiology*; D001783:Blood Flow Velocity; D019842:Ciliary Arteries / Q000502:physiology; D005260:Female; D005902:Glaucoma, Open-Angle / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D009412:Nerve Fibers / Q000473:pathology*; D009898:Optic Disk / Q000473:pathology*; D009915:Orbit / Q000098:blood supply*; D012161:Retinal Artery / Q000502:physiology; D012165:Retinal Ganglion Cells / Q000473:pathology*; D012171:Retinal Vessels / Q000502:physiology*; D041623:Tomography, Optical Coherence
keywords: Glaucoma; Imaging; Optic Nerve; Physiology; Retina