title: En Face Doppler Optical Coherence Tomography Measurement of Total Retinal Blood Flow in Diabetic Retinopathy and Diabetic Macular Edema.
abstract: OBJECTIVE
  Alterations in ocular blood flow play an important role in the pathogenesis and progression of diabetic retinopathy (DR). However, the measurement of retinal blood flow in clinical studies has been challenging. En face Doppler optical coherence tomography (OCT) provides an effective method for measuring total retinal blood flow (TRBF) in the clinic.
  
  
  OBJECTIVE
  To investigate TRBF in eyes with DR of varying severity, with or without diabetic macular edema (DME), using en face Doppler OCT.
  
  
  METHODS
  This was a cross-sectional study conducted from May 23, 2014, to January 11, 2016, which analyzed 41 eyes with DR from 31 diabetic patients, 20 eyes without DR from 11 diabetic patients, and 16 eyes from 12 healthy age-matched controls, all at the New England Eye Center in Boston, Massachusetts.
  
  
  METHODS
  Participants were imaged with a high-speed, swept-source OCT prototype at 1050-nm wavelength using repeated en face Doppler OCT raster scans, comprising 600 × 80 axial scans and covering a 1.5 × 2-mm2 area centered at the optic disc. The TRBF was automatically calculated using custom Matlab software.
  
  
  RESULTS
  This study included 41 eyes with DR from 31 diabetic patients (mean [SD] age, 62.8 [13.4] years; 12 were female patients), 20 eyes without DR from 11 diabetic patients (mean [SD] age, 58.8 [10.1] years; 5 were female patients), and 16 eyes from 12 healthy age-matched controls (mean [SD] age, 57.9 [8.1] years; 8 were female participants). The mean (SD) TRBF was 28.0 (8.5) µL/min in the eyes with DME, 48.8 (13.4) µL/min in the eyes with DR but without DME, 40.1 (7.7) µL/min in the diabetic eyes without retinopathy, and 44.4 (8.3) µL/min in age-matched healthy eyes. A difference in TRBF between the eyes with DME that were treated and the eyes with DME that were not treated was not identified. The TRBF was consistently low in the eyes with DME regardless of DR severity. The eyes with moderate nonproliferative DR but without DME exhibited a wide range of TRBF from 31.1 to 75.0 µL/min, with the distribution being highly skewed.
  
  
  CONCLUSIONS
  High-speed en face Doppler OCT can measure TRBF in healthy and diabetic eyes. Diabetic eyes with DME exhibited lower TRBF than healthy eyes (P ≤ .001). Further longitudinal studies of TRBF in eyes with DR would be helpful to determine whether reduced TRBF is a risk factor for DME.
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge2Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge.
authors.forename: ByungKun
authors.initials: B
authors.lastname: Lee
authors.affiliation: New England Eye Center, Tufts Medical Center, Boston, Massachusetts4Federal University of São Paulo, School of Medicine, São Paulo, Brazil.
authors.forename: Eduardo A
authors.initials: EA
authors.lastname: Novais
authors.affiliation: New England Eye Center, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Nadia K
authors.initials: NK
authors.lastname: Waheed
authors.affiliation: New England Eye Center, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Mehreen
authors.initials: M
authors.lastname: Adhi
authors.affiliation: New England Eye Center, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Talisa E
authors.initials: TE
authors.lastname: de Carlo
authors.affiliation: New England Eye Center, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Emily D
authors.initials: ED
authors.lastname: Cole
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge2Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Moult
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge2Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge.
authors.forename: WooJhon
authors.initials: W
authors.lastname: Choi
authors.affiliation: New England Eye Center, Tufts Medical Center, Boston, Massachusetts5Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, England.
authors.forename: Mark
authors.initials: M
authors.lastname: Lane
authors.affiliation: New England Eye Center, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Caroline R
authors.initials: CR
authors.lastname: Baumal
authors.affiliation: New England Eye Center, Tufts Medical Center, Boston, Massachusetts.
authors.forename: Jay S
authors.initials: JS
authors.lastname: Duker
authors.affiliation: Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge2Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge.
authors.forename: James G
authors.initials: JG
authors.lastname: Fujimoto
mesh_terms: D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D004301:Doppler Effect; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008269:Macular Edema / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow / Q000502:physiology*; D012160:Retina / Q000473:pathology / Q000503:physiopathology*; D012171:Retinal Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence / Q000379:methods*