Vascular Metrics and Non-Perfusion Area Measured by Wide-Field Swept-Source OCT-Angiography (WF-SSOCTA) in Different Stages of Diabetic Retinopathy

Abstract

Purpose : Previous studies with smaller cohorts have shown decreased vessel density with increasing diabetic retinopathy (DR) severity. Recently, there has been increasing interest in WF fundus photography and fluorescein angiography in the management of diabetic eye disease. We explore the added value of WF SS-OCTA in a large prospective observational study of diabetic patients compared to controls.

Methods : We imaged 402 eyes of 241 patients (70 eyes of 55 control patients and 332 eyes of 186 diabetic patients) using WF SS-OCTA between December 2018 to September 2020. 6x6mm and 12x12mm scans centered on the fovea were analyzed using ARI Network (Zeiss Portal) for vessel density (VD), vessel skeleton density (VSD), foveal avascular zone (FAZ) raw size, circularity and perimeter; and ImageJ for non-perfusion area (NPA) on 12x12mm scans only. Mixed-effects multivariate regression models were used to test for significance.

Results : Among patients with diabetes (median age 59 years), 45 eyes of 24 patients had no DR, 71 eyes of 40 patients had mild non-proliferative DR (NPDR), 45 eyes of 28 patients had moderate NPDR, 28 eyes of 16 patients had severe NPDR, and 133 eyes of 78 patients had proliferative DR (PDR). Trend analysis revealed a progressive decline in VD and VSD with increasing DR severity (p<0.05). PDR patients had an increased FAZ raw size (β=0.14, p=0.03), perimeter (β=0.83, p=0.03), and irregularity (β=-0.10, p<0.001). Also, the mild (β=-0.07, p=0.047) and moderate NPDR (β=-0.10, p=0.01) group had irregular FAZ on 12x12mm scans. Controlling for DR severity and age, diabetic macular edema was associated with a more irregular FAZ on 6x6mm scans (β=-0.06, p=0.004). NPDR and PDR had greater NPA versus controls (p<0.001). On receiver operating curve (ROC) analysis, wide-field NPA was the best test to detect the presence of DR, area under the curve (AUC) 0.97.

Conclusions : Herein, we present a comprehensive study of a large cohort of DR patients imaged on the WF SS-OCTA. The enhanced resolution and larger area coupled with a bigger sample size validates prior work that indicated VD reductions with increased DR severity. Furthermore, our work highlights the importance of NPA which can be more readily and repeatedly measured with WF SS-OCTA.

This is a 2021 ARVO Annual Meeting abstract.

 

Comparative VD and VSD in our cohort.

 

AUC ROC for the investigated study parameters to diagnose the presence of DR.