The goal of this study was to evaluate the perifoveal capillary bed and to analyze areas of non-flow using optical coherence tomography angiography (OCT-A) in patients presenting with diabetic retinopathy (DR), correlating them to the severity of DR, type of diabetes and visual acuity (VA).
The non-flow area (NFA) and foveal avascular zone (FAZ) in the superficial (SCP) and deep capillary plexus (DCP) were calculated using OCT-A imaging of patients with DR followed between July 2015 and March 2016 at the Jules Gonin Eye Hospital (Lausanne, Switzerland). Disease severity was classified using the Early Treatment Diabetic Retinopathy Study (ETDRS) classification. Analysis of variance was used to correct for correlation between eyes.
Seventy-eight eyes of 53 patients were included (29 men; 44 right eyes). There were 45 eyes with non-proliferative DR (NPDR; stage 1 [n=14], stage 2 [n=7], and stage 3 [n=24]) and 33 with proliferative DR (PDR; stage 1 [n=17], stage 2 [n=16]) included, among which 26 had type I diabetes and 52 type II diabetes. The mean Best Corrected Visual Acuity (BCVA) was 78.5 letters. The mean NFA in the SCP differed according to diabetes type and stage of DR (type 1 diabetes: NPDR, 0.76±0.3, PDR, 1.24±0.7; type 2 diabetes: NPDR, 1.46±0.7, PDR, 1.57±0.7).
The NFA, measured by OCTA, may be a useful indicator of DR severity, especially in the superficial capillary plexus. Loss of visual acuity might be correlated with increasing NFA (excluding the FAZ or not), primarily among patients with type II diabetes and NPDR.