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YIJUN CAI, Jibran Mohamed-Noriega, Pearse Andrew Keane, Catherine A Egan, Adnan Tufail, Dawn A Sim; Longitudinal analysis of the foveal avascular zone in diabetic retinopathy using optical coherence tomography angiography.. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5498.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the variance of different methods for analyzing Optical Coherence Tomography Angiography (OCTA)- derived images of the foveal avascular zone (FAZ) in diabetic retinopathy.
Patients with evidence of diabetic retinopathy and OCTA imaging on two separate visits were included. A commercial OCTA system (AngioVue, Optovue, Inc. Fremont, CA, USA) was used to acquire 3x3mm images of the superficial and deep vessel layers, centered on the fovea. FAZ area (mm2), perimeter (mm), and circularity were analyzed using ImageJ. The F-test was used to compare the variances within each parameter in the superficial and deep vessel layers.
12 eyes of 6 patients were included. All eyes had been previously diagnosed with diabetic macular ischemia of varying severities; 4/12 (33.3%) questionable, 4/12 (33.3%) mild, 2/12 (16.7%) moderate, and 2/12 (16.7%) severe. The mean time between OCTA imaging was 104 days (range 56 to 210). In the superficial layer, the median difference (variance) in FAZ area was 0.045 (0.012), FAZ perimeter 0.243 (2.49), and FAZ circularity 0.001 (0.005). In the deep layers, median difference (variance) in FAZ area was 0.15 (0.016), FAZ perimeter 0.138 (2.55), and FAZ circularity 0.061 (0.005). There were no significant differences in the variance ratios for superficial and deep layer analysis of FAZ area 1.30 (p=0.67), perimeter 1.02 (p=0.91), or circularity 1.09 (p=0.88).
OCTA is non-invasive method for the rapid acquisition of images of the retinal vasculature. This promising new technology lends itself to longitudinal imaging in diabetic retinopathy for the purpose of monitoring of diabetic macular ischemia. We demonstrate the feasibility of using OCTA for this purpose and show that parameters such as area, perimeter and circularity can be used for quantification of the FAZ in both superficial and deep vessel layers.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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