In Vivo Assessment of Macular Vascular Density in Healthy Human Eyes Using Optical Coherence Tomography Angiography

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To quantify density of macular vascular networks over regions of interest in healthy subjects using optical coherence tomography angiography (OCTA). Prospective cross-sectional study. Setting was the Retina and Oncology Services of Wills Eye Hospital. Subjects with no known systemic disease and without retinal pathology were included. OCTA was performed on a 3× 3-mm region centered on the macula and en face angiograms of the superficial and deep vascular networks were acquired. Vascular density was calculated using an automated image thresholding method over regions of interest. Foveal and parafoveal vascular density were calculated. The differences between vascular networks, sexes, and fellow eyes and correlation between vascular density, signal strength, and age, as well as reproducibility of measurements, were evaluated. A total of 198 healthy eyes were imaged, from which 163 eyes of 122 subjects were included based on image quality criteria. In the parafoveal region, deep vascular density was significantly higher than the superficial (52% ± 2.4% vs 46% ± 2.2%; P < .001), whereas the opposite was found in the foveal region (27% ± 5.2% vs 32% ± 3.2%; P < .001). All vascular density measurements were statistically similar in fellow eyes and there was no sex difference (P > .05). There was a negative correlation between vascular density and age that persisted upon adjusting for signal strength. Vascular density measurements were highly correlated between separate imaging sessions with intraclass correlation coefficients of over 0.85 for all assessments. Calculation of vascular density using OCTA is a reproducible and noninvasive method to quantitate individual networks within the macula. Understanding normal values and their correlations could affect clinical evaluation of the macula in healthy patients and disease states.