Comparison of diabetic retinopathy classification using fluorescein angiography and optical coherence tomography angiography

Purpose To analyse and compare the classification of eyes with diabetic retinopathy using fluorescein angiography (FA) and optical coherence tomography angiography (OCTA) performed either with AngioPlex or AngioVue. Methods This was an observational cross-sectional study of 50 eyes from 26 diabetic subjects. Two independent graders classified the FA angiograms, to assess the presence and severity of several characteristics according to the ETDRS Report 11, and a similar evaluation was performed for each 3x3 mm OCTA image from the superficial retinal layer and for the full retina slab. Results Percentages of non-gradable images for the outline of foveal avascular zone (FAZ) in the central subfield (CSF) were 29.0% for FA, 12.0% for AngioVue and 3.0% for AngioPlex. For capillary loss, percentages of non-gradable images in the CSF were 25.0% for FA, 11% for AngioVue and 0.0% for AngioPlex. For the inner ring (IR), percentages of non-gradable images were 12.5% for FA, 11.5% for AngioVue and 0.5% for AngioPlex. Agreement between graders was substantial for outline of FAZ. For capillary loss, the agreement was fair for the CSF, and moderate for the IR. Conclusions The OCTA allows better discrimination of the CSF and parafoveal macular microvasculature than FA, especially for FAZ disruption and capillary dropout, without the need of an intravenous injection of fluorescein. In addition, FA had also a higher number of non-gradable images. The OCTA can replace with advantage the FA, as a non-invasive and more sensitive procedure for detailed morphological evaluation of central macular vascular changes.