title: Quantitative Optical Coherence Tomography Angiography of Radial Peripapillary Capillaries in Glaucoma, Glaucoma Suspect, and Normal Eyes.
abstract: OBJECTIVE
  To evaluate the quantitative characteristics of the radial peripapillary capillary (RPC) network in glaucoma, glaucoma suspect, and normal eyes using speckle variance optical coherence tomography angiography (OCT-A). To determine correlations between RPC density, nerve fiber layer (NFL) thickness, and visual field indices.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  OCT-A images of RPCs were acquired at a single institution using a custom-built 1060 nm system from 3 groups: unilateral glaucoma (10 eyes from 5 subjects), glaucoma suspects (6 eyes from 3 subjects), and normal control eyes (16 eyes from 9 normal subjects). Peripapillary NFL thickness measurements were determined using spectral-domain optical coherence tomography. Glaucoma and glaucoma suspects also underwent automated 30-2 Humphrey visual field analysis. Manual tracing techniques were used to quantify RPC density in the OCT-A images. Data were analyzed using a linear mixed model with 1 fixed-effect covariate. Correlations between main outcome measures (RPC density, NFL thickness, and visual field index) were determined.
  
  
  RESULTS
  Mean age was not significantly different between the 3 groups (P = .25). The density of RPCs was significantly lower in glaucomatous eyes compared with matched-peripapillary regions in the fellow eye, glaucoma suspect group, and normal group (all P < .001). RPC density was strongly correlated with NFL thickness (P < .001) and visual field index (P < .001).
  
  
  CONCLUSIONS
  Significant reductions in RPC density were correlated with sites of NFL decrease and visual field loss in glaucoma. Speckle variance OCT-A allows visualization and quantification of RPCs and may therefore be a useful tool for indirectly quantifying and monitoring retinal ganglion cell axonal injury in glaucoma.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Zaid
authors.initials: Z
authors.lastname: Mammo
authors.affiliation: School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Morgan
authors.initials: M
authors.lastname: Heisler
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada; Vitreous Retina Macula Consultants of New York, New York, New York; LuEsther T. Mertz Retinal Research Center, Eye, Ear and Throat Hospital, New York, New York; Department of Physiology and Pharmacology, Centre for Ophthalmology and Visual Science, Lions Eye Institute, The University of Western Australia, Nedlands, Western Australia, Australia.
authors.forename: Chandrakumar
authors.initials: C
authors.lastname: Balaratnasingam
authors.affiliation: School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Sieun
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Physiology and Pharmacology, Centre for Ophthalmology and Visual Science, Lions Eye Institute, The University of Western Australia, Nedlands, Western Australia, Australia.
authors.forename: Dao-Yi
authors.initials: DY
authors.lastname: Yu
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada; School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Paul
authors.initials: P
authors.lastname: Mackenzie
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Steven
authors.initials: S
authors.lastname: Schendel
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Merkur
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: Kirker
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: David
authors.initials: D
authors.lastname: Albiani
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Navajas
authors.affiliation: School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Mirza Faisal
authors.initials: MF
authors.lastname: Beg
authors.affiliation: Department of Physiology and Pharmacology, Centre for Ophthalmology and Visual Science, Lions Eye Institute, The University of Western Australia, Nedlands, Western Australia, Australia.
authors.forename: William
authors.initials: W
authors.lastname: Morgan
authors.affiliation: School of Engineering Science, Simon Fraser University, Burnaby, British Columbia, Canada. Electronic address: msarunic@sfu.ca.
authors.forename: Marinko V
authors.initials: MV
authors.lastname: Sarunic
mesh_terms: D000328:Adult; D000368:Aged; D002196:Capillaries / Q000000981:diagnostic imaging / Q000473:pathology; D003430:Cross-Sectional Studies; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005901:Glaucoma / Q000503:physiopathology*; D064368:Healthy Volunteers; D006801:Humans; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology; D009798:Ocular Hypertension / Q000503:physiopathology; D009898:Optic Disk / Q000098:blood supply*; D012165:Retinal Ganglion Cells / Q000473:pathology; D012171:Retinal Vessels / Q000000981:diagnostic imaging / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D014794:Visual Fields / Q000502:physiology; D055815:Young Adult