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Original Investigation
August 2018

Automated Quantification of Nonperfusion Areas in 3 Vascular Plexuses With Optical Coherence Tomography Angiography in Eyes of Patients With Diabetes

Author Affiliations
  • 1Casey Eye Institute, Oregon Health and Science University, Portland
  • 2Optovue Inc, Fremont, California
  • 3Georgetown University School of Medicine, Washington, DC
JAMA Ophthalmol. 2018;136(8):929-936. doi:10.1001/jamaophthalmol.2018.2257
Key Points

Question  How useful are automatically quantified nonperfusion parameters from projection-resolved optical coherence tomography angiography in patients with diabetes?

Findings  In this cross-sectional study of 71 patients with diabetes and 39 healthy control individuals, avascular areas detected from projection-resolved optical coherence tomography angiography retinal plexuses distinguished between control individuals and various levels of diabetic retinopathy severity. These biomarkers were less dependent on age and signal strength and more sensitive than some commercially available vessel density measurements.

Meaning  Automatically quantified avascular areas from projection-resolved optical coherence tomography angiography of individual plexuses in patients with diabetes may offer a more reliable, sensitive method to evaluate diabetic vascular abnormalities than previous methods.

Abstract

Importance  Diabetic retinopathy (DR) is a leading cause of vision loss that is managed primarily through qualitative clinical examination of the retina. Optical coherence tomography angiography (OCTA) may offer an objective and quantitative method of evaluating DR.

Objective  To quantify capillary nonperfusion in 3 vascular plexuses in the macula of eyes patients with diabetes of various retinopathy severity using projection-resolved OCTA (PR-OCTA).

Design, Setting, and Participants  Cross-sectional study at a tertiary academic center comprising 1 eye each from healthy control individuals and patients with diabetes at different severity stages of retinopathy. Data were acquired and analyzed between January 2015 and December 2017.

Main Outcomes and Measures  Foveal avascular zone area, extrafoveal avascular area (EAA), and the sensitivity of detecting levels of retinopathy.

Results  The study included 39 control individuals (20 women [51%]; mean [SD] age, 43.41 [19.37] years); 16 patients with diabetes without retinopathy (8 women [50%]; mean [SD] age, 56.50 [12.43] years); 23 patients with mild to moderate nonproliferative DR (18 women [78%] ; mean [SD] age, 62.48 [10.55] years); and 32 patients with severe nonproliferative DR or proliferative DR (12 women [38%]; mean age, 53.41 [14.05] years). Mean (SD) foveal avascular zone area was 0.203 (0.103) mm2 for control individuals, 0.192 (0.084) mm2 for patients with diabetes without retinopathy, 0.243 [0.079] mm2 for mild to moderate nonproliferative DR, and 0.359 (0.275) mm2 for severe nonproliferative DR or proliferative DR. Mean (SD) EAA in whole inner retinal slab in these groups, respectively, were 0.020 (0.031) mm2, 0.034 (0.047) mm2, 0.038 (0.040) mm2, and 0.237 (0.235) mm2. The mean (SD) sum of EAA from 3 segmented plexuses in each of the respective groups were 0.103 (0.169) mm2, 0.213 (0.242) mm2, 0.451 (0.243) mm2, and 1.325 (1.140) mm2. With specificity fixed at 95%, using EAA in inner retinal slab, the sensitivity of detecting patients with diabetes from healthy control individuals was 28% (95% CI, 18%-40%), 31% for patients with DR (95% CI, 19%-45%), and 47% for patients with severe DR (95% CI, 29%-65%) from whole inner retinal EAA. With the sum of EAA from 3 individual plexuses, the sensitivities were 69% (95% CI, 57%-80%), 82% (95% CI, 70%-91%), and 97% (95% CI, 85%-100%), respectively. Avascular areas were not associated with signal strength index. The commercial vessel density from the 2-plexus scheme distinguished the groups with lower sensitivity and were dependent on SSI.

Conclusions and Relevance  Automatically quantified avascular areas from a 3-layer segmentation scheme using PR-OCTA distinguished levels of retinopathy with a greater sensitivity than avascular areas from unsegmented inner retinal slab or measurements from a commercially available vessel density in 2-layer scheme. Additional studies are needed to investigate the applicability of nonperfusion parameters in clinical settings.

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