An Update on Optical Coherence Tomography Angiography in Diabetic Retinopathy

Abstract

Optical coherence tomography angiography (OCTA) is a novel non-invasive imaging modality for 3-dimensional visualization of retinal and optic nerve capillary networks. In this article, a comprehensive review of relevant original articles in the PubMed database was performed using the search terms "diabetic retinopathy," "diabetic macular edema," "diabetes mellitus," and "optical coherence tomography angiography." OCTA was found to detect microvascular changes early in diabetes mellitus, even before they become clinically evident. Morphological and qualitative assessment of vascular changes can help to determine the pathophysiological processes, activity, treatment, and follow-up of diabetic retinopathy (DR). Vessel density and foveal avascular zone are the most investigated quantified indices shown to be early predictors of DR, correlated to DR severity and visual function, and useful in predicting response to treatment. OCTA has shown to be a promising alternative to fluorescein angiography in the management of DR. Further studies are warranted to determine the role of OCTA in the routine clinical management of DR.

Keywords: Deep Capillary Plexus; Diabetic Retinopathy; Foveal Avascular Zone; Ischemia; Optical Coherence Tomography Angiography; Superficial Capillary Plexus; Vessel Density.

Figure 1

Montage optical coherence tomography angiography image of the optic disc and macula in a patient with diabetic retinopathy. Vascular changes are shown, including enlarged foveal avascular zone, optic disc neovascularization (long arrow), macular neovascularization (short arrow), microvascular tortuosity (arrowhead), and extensive capillary nonperfusion (star).

Figure 2

Optical coherence tomography images from the superficial capillary plexus (a), deep capillary plexus (b), and choriocapillaris (c) slabs with corresponding structural optical coherence tomography images in a patient with diabetic retinopathy. The figure shows microaneurysm (white long arrow), capillary non-perfusion (white short arrow), enlarged foveal avascular zone with a notch (red short arrow), focal microvascular tortuosity and dilation (yellow arrow), focal areas of true signal impairment (yellow dotted arrow) and shadow artifact (red dotted arrow).