The purpose of our study was to quantitatively assess retinal and choroidal microvascular changes according to diabetic retinopathy (DR) stage using optical coherence tomography (OCT)-derived parameters. Furthermore, we aimed to evaluate diagnostic ability of OCT-derived vascular parameters for determining DR progression.


Retrospective cohort study.


One-hundred-thirty-two eyes of 81 patients with type 2 DM and 42 eyes of 28 healthy controls were included.


Subjects underwent swept-source optical coherence tomography (SS-OCT) raster scans and OCT angiography volume scans. We quantitatively analyzed OCT-derived vascular parameters at the superficial capillary plexus (SCP) and deep capillary plexus (DCP) using Image J software. We collected data on glycated hemoglobin, fasting blood sugar, systolic and diastolic blood pressure.

Main Outcome Measures:

Foveal avascular zone (FAZ) area, FAZ perimeter, FAZ circulatory index, retinal vessel density, retinal vessel length density, and choroidal vascularity index (CVI).


We divided eyes into healthy controls (n = 42), no DR (n = 30), mild non-proliferative DR (NPDR) (n = 22), moderate NPDR (n = 23), severe NPDR (n = 42), and proliferative DR (PDR) (n = 15). The FAZ area and FAZ perimeter correlated positively with worsening DR severity; the FAZ circularity index, retinal vessel density, retinal vessel length density, and CVI correlated negatively with worsening severity. The highest AUCs were similar for SCP and DCP FAZ circulatory indexes in discriminating no DR from other stages. The SCP FAZ circulatory index demonstrated the highest AUCs in discriminating early from advanced DR (including severe NPDR and PDR). In early DR stages, the decreasing DCP FAZ circulatory index trend was remarkable.


There were significant quantitative changes in retinal and choroidal vascular parameters with DR progression. Before DR presents, functional circulatory disturbances in retinal and choroidal vasculatures occur. As DR progresses, DCP retinal microvasculature changes precede SCP changes.


Mirinae KIM, Young-Hoon PARK
Seoul Saint Mary’s Hospital
South Korea
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