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Original Investigation
February 9, 2017

En Face Doppler Optical Coherence Tomography Measurement of Total Retinal Blood Flow in Diabetic Retinopathy and Diabetic Macular Edema

Author Affiliations
  • 1Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge
  • 2Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge
  • 3New England Eye Center, Tufts Medical Center, Boston, Massachusetts
  • 4Federal University of São Paulo, School of Medicine, São Paulo, Brazil
  • 5Queen Elizabeth Hospital Birmingham, University Hospitals Birmingham NHS Foundation Trust, Birmingham, England
JAMA Ophthalmol. Published online February 9, 2017. doi:10.1001/jamaophthalmol.2016.5774
Key Points

Question  What is the role of retinal blood flow (RBF) in the pathogenesis and progression of diabetic retinopathy (DR)?

Findings  A cross-sectional investigation of total RBF (TRBF) using en face Doppler optical coherence tomography (OCT) demonstrated that the TRBF was lower in eyes with diabetic macular edema (DME) (mean [SD], 28.0 [8.5] µL/min) than in either eyes with DR but without DME (48.8 [13.4] µL/min) or healthy eyes (44.4 [8.3] µL/min).

Meaning  The measurements of TRBF suggest that ischemia may be associated with DME, although the influence of anti–vascular endothelial growth factor treatments must be investigated.

Abstract

Importance  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.

Design, Setting, and Participants  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.

Main Outcomes and Measures  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 and Relevance  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.

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