Detection of Venous Loops in Diabetic Retinopathy using Widefield Swept-Source Optical Coherence Tomography Angiography

Abstract

Purpose : Retinal venous loops (RVL) are rare manifestations of diabetic retinopathy (DR) usually identified by color fundus photography. The prevalence and its predictive value reported in the literature may be underestimated due to the limitations of detection techniques. This study investigated the prevalence of RVL and their associated microvascular changes using widefield swept-source optical coherence tomography angiography (WF SS-OCTA).

Methods : In this retrospective, observational study at Mass Eye and Ear from December 2018 to December 2019, diabetic patients with proliferative diabetic retinopathy (PDR), non-proliferative diabetic retinopathy (NPDR) and without DR were included. All patients were imaged with a WF SS-OCTA using Angio 6mm×6mm and Montage 15mm×15mm scan. Images were independently evaluated by two graders for the presence or absence of RVL and other DR lesions including nonperfusion areas (NPAs) and neovascularization (NV). RVL were divided into two types according to the branching level of the feeder vessel. Type I has loops on the larger veins encompassing the third and second branching level from the central retinal vein; type II has loops on the fourth or higher branching level

Results : Two hundred and thirty-three eyes of 156 diabetic patients, with no DR (n =31 eyes), NPDR (n = 98 eyes) and PDR (n = 104 eyes), were included in this study. The prevalence of RVL in DM and PDR was 11.2 % (26/233) and 19.2% (20/104), respectively. There were significantly more eyes with RVL in PDR than NPDR (p<0.05). Type I RVL occurred in 5 eyes, while 23 eyes with type II RVL. Although none of the RVL were found to have adjacent NV, the rate of accompanied NPAs in type I RVL was higher than that in type II (6/7, 85% vs 8/19, 42%, p<0.05).

Conclusions : WF SS-OCTA is useful for identification of RVL in patients with DR. Given the increased prevalence of RVL in more advanced diabetic retinopathy, RVL may represent another referable feature as part of a potential OCTA screening system for diabetic eye disease. Larger longitudinal studies will be needed to assess the relationship between RVL with NPAs and NV on OCTA.

This is a 2020 Imaging in the Eye Conference abstract.