Retinal Capillary Density and Foveal Avascular Zone Area Are Age-Dependent: Quantitative Analysis Using Optical Coherence Tomography Angiography

The purpose of this study was to quantify retinal capillary density and the foveal avascular zone (FAZ) area in normal subjects according to age, using optical coherence tomography angiography (OCTA).All eyes in this cross-sectional study underwent OCTA using RTVue XR Avanti with AngioVue. OCTA scans were analyzed and processed, and vessel density and FAZ dimensions were calculated.A total of 113 normal eyes from 70 subjects were included (30 males, 40 females; mean 48 ± 20 years of age). The mean vessel density and FAZ dimensions were significantly smaller in the superficial retinal capillary plexus (SCP) than in the deep retinal capillary plexus (DCP), using quantitative OCTA analysis (all P< 0.0001). With 3 × 3-mm scans, the mean vessel density was 13.431 ± 1.758 mm-1 in the SCP, 18.812 ± 1.796 mm-1 in the DCP, and 5.913 ± 1.308 mm-1 and 10.447 ± 1.262 mm-1 with 6 × 6-mm scans in the SCP and DCP, respectively. Mean FAZ areas were 0.289 ± 0.108 mm2 at the SCP and 0.614 ± 0.200 mm2 at the DCP. Age was a predictor of SCP and DCP vessel density and FAZ area in the SCP. Vessel density decreased 0.0393 mm-1 (0.26%) per year in the SCP and 0.0574 mm-1 (0.27%) per year in the DCP. FAZ areas increased 0.0014 mm2 (0.63%) and 0.0011 mm2 (0.20%) per year in the SCP and DCP, respectively.SCP and DCP vessel density decreased with increasing age, while FAZ area increased with age. Normal age-matched measurements provide important standardized values that may facilitate management of retinal vascular disorders.