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shota yasukura, Tomoaki Murakami, Kiyoshi Suzuma, Tatsuya Yoshitake, Masahiro Fujimoto, Hideo Nakanishi, Maho Oishi, Akitaka Tsujikawa; Diabetic Capillary Nonperfusion in the Macula and Extramacular areas on Optical Coherence Tomography Angiography. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1056.
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The pathogenesis of the nonperfused area (NPA) remains ill-defined despite its clinical relevance. Optical coherence tomography angiography (OCTA) enables us to evaluate three-dimensional changes in retinal vasculature and delineates deep capillary plexus as collateral vessels. In this study, we considered the watershed of capillaries and compared the NPAs between the macula and the extramacular areas in eyes with proliferative diabetic retinopathy (PDR).
In this retrospective study, 48 eyes of 32 patients with PDR are consecutively participated. OCTA images centered on the optic disc (12 x 12 mm square) were obtained using swept source OCTA (Plex Elite 9000 [Carl Zeiss Meditec Inc.]). Considering the watershed of capillaries, we defined the vascular arcade using the main trunks of arteries on the deep OCTA images. The macular areas demarcated by vascular arcades and the extramacular areas were determined. In addition, the inner ring was within 6 mm diameter centered on the optic disc, and the outer ring was from 6 to 11 mm diameter. The NPAs were defined as the areas without capillaries in all retinal layers on OCTA images, and the percentages of the NPAs were calculated.
Within the macula, most arteries were present mainly in the superficial layer, whereas those in the vascular arcades or extramacular areas were delineated from the superficial to the deep layers, suggesting that such vessels correspond to the watershed. The extramacular areas had greater percentages of the NPAs than the macula in the inner (median 2.78 % [interquartile range, 1.60 – 5.69] vs. 0.67 % [0.31 – 1.28], P<0.001) or outer ring (22.92 % [15.66 – 37.44] vs. 2.05 % [0.91 – 5.20], P<0.001). The percentage of the NPAs was higher in the outer ring than that in the inner ring (16.04 % [11.12 – 26.27] vs. 1.85 % [1.30 – 3.69], P<0.001). The age was negatively associated with the extramacular areas within the inner or outer rings (ρ=-0.299, P=0.039 or ρ=-0.349, P=0.015, respectively).
These data suggest that the mechanisms of the NPA development are different between the macula and the extramacular areas in PDR. It may allow us to speculate that the arteries within the macula enable the compensation of blood flow to each other mediated via deep capillary plexus, compared to those in the extramacular areas as the watershed of vascular supply.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.
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