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Ayesha Nuri Karamat, Siva Balasubramanian, Jianqin Lei, Elmira Baghdasaryan, Srinivas R. Sadda; Repeatability of Foveal Avascular Zone Morphometry Using Optical Coherence Tomography Angiography En Face Images. Invest. Ophthalmol. Vis. Sci. 2018;59(9):2868.
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© ARVO (1962-2015); The Authors (2016-present)
Optical coherence tomographic angiography (OCTA) studies have demonstrated abnormalities of the foveal avascular zone (FAZ) in various retinal diseases, both qualitatively and quantitatively. In order to reliably use FAZ metrics to distinguish disease from normal, the repeatability of these measures must be defined, which was the focus of this study.
In this IRB approved prospective cross-sectional study, 21 healthy volunteers (42 eyes) and 22 patients with retinal disease (22 eyes; including 14 with age-related macular degeneration, 3 with epiretinal membrane, 2 with diabetic retinopathy, 2 with myopic macular degeneration, and 1 with retinal vein occlusion) were enrolled. Three repeated scans with 3 same-model OCTA devices (Cirrus HD-OCT model 5000; Carl Zeiss Meditec, Inc) for a total of 9 acquisitions were obtained for each eye, using either a 3 × 3 mm or 6 × 6 mm (randomly assigned) scanning pattern (Figure 1). The area, perimeter and circularity of the FAZ of the superficial capillary plexus were automatically generated by the instrument software (Figure 1). The repeatability of the measurements was evaluated using Intraclass correlation coefficients (ICC) and coefficient of variation (CV).
Among the 21 (42 eyes) healthy volunteers, 8 were men and 13 were women with a mean age of 36 ± 6 years. Among the 22 patients (22 eyes) with retinal diseases, 15 were men and 7 were women; with a mean age of 79 ± 9 years. The mean values, standard deviation (SD), and coefficient of variation (CV) for each parameter and for each scan pattern are shown in Table 1. The CV was < 7% for all parameters. The ICC among the 9 acquisitions for 3x3 mm scans was 0.97 (95% confidence interval (CI): 0.95-0.98) for FAZ area, 0.92 (95% CI: 0.87-0.96) for FAZ perimeter, and 0.86 (95% CI: 0.77-0.92) for FAZ circularity. For the 9 acquisitions with the 6x6 mm pattern, the ICC was 0.97 (95% CI: 0.95-0.98) for FAZ area, 0.94 (95% CI: 0.90-0.97) for FAZ perimeter, and 0.90 (95% CI: 0.84-0.95) for FAZ circularity.
Quantitative FAZ metrics from the superficial retinal vasculature on OCTA can be obtained automatically with a high level of repeatability.
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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