Abstract
Purpose :
To analyse and compare the classification of eyes with Diabetic Retinopathy (DR) using Fluorescein Angiography (FA) and Optical Coherence Tomography-Angiography (OCT-A), with either AngioPlex or AngioVue.
Methods :
Twenty nine eyes (29) eyes from 15 diabetic subjects underwent FA (HRA Spectralis), color fundus photography (CFP) and OCT-A, 3x3mm scan, using two different devices (Zeiss AngioPlex prototype and Optovue AngioVue OCTA system). ETDRS DR levels were obtained from CFP. From OCT-A the superficial retinal vascular layer (SRL) were depicted as an en-face image and exported as image file. For FA, 20 degrees images from field 2 of the initial stage of the procedure were also exported. Two independent graders (CAN and MS) classified the FA using the ETDRS Report 11, and a similar evaluation was performed for OCT-A. Foveal avascular zone (FAZ) was also measured using an image processing program (ImageJ) and the free hand selection tool. Descriptive statistics were calculated.
Results :
The mean age of the diabetic patients was 66.1±7.8 years (range 52-76) and 34.5% were females. The FAZ size varied widely (from 0.146 to 0.670 mm2 for Zeiss AngioPlex, from 0.113 to 0.816 mm2 for AngioVue OCTA system and from 0.092 to 0.741 mm2 for FA). Outline of FAZ, capillary loss, arteriolar abnormalities and capillary dilatation showed a higher percentage of ungradable features using FA in comparison with both OCT-A devices. Gradable images for outline of FAZ in central subfield (CSF) were 70.0% with FA, 86.2% with AngioPlex, and 75.9% with AngioVue (FA vs AngioPlex p=0.006; FA vs AngioVue p=0.100). For capillary loss, gradable images in the inner ring were 56.9% with FA, 69.8% with AngioPlex, and 64.7% with AngioVue (FA vs AngioPlex p=0.169; FA vs AngioVue p=0.732).
Conclusions :
The OCT-A allows better discrimination of the CSF and parafoveal macular microvasculature than FA, especially for FAZ rupture and capillary loss, without the need of an intravenous injection of fluorescein. In addition, FA had also a higher number of ungradable features. The OCT-A can replace with advantage the FA as a non-invasive and more sensitive procedure for detailed morphological evaluation of retinal vascular changes.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.