Quantitative Analysis of Three Distinct Retinal Capillary Plexuses in Healthy Eyes Using Optical Coherence Tomography Angiography.

Purpose To identify and quantify the three distinct retinal capillary plexuses and the foveal avascular zone (FAZ) in healthy subjects according to age using optical coherence tomography angiography (OCTA) with novel projection artifact removal (PAR) software and improved segmentation. Methods All eyes in this cross-sectional study underwent OCTA imaging using RTVue XR Avanti with novel PAR AngioVue software. OCTA scans were analyzed and the three main parafoveal retinal capillary plexuses were segmented and vessel density and FAZ area were calculated. Results A total of 152 normal eyes from 95 subjects (39 males, 56 females, mean age 42 ± 25 years) were included. The mean vessel density was 15.48 ± 2.04 mm-1 in the superficial retinal capillary plexus (SCP), 15.28 ± 1.82 mm-1 in the intermediate retinal capillary plexus (ICP), and 16.33 ± 2.32 mm-1 in the deep retinal capillary plexus (DCP) for 3 × 3-mm OCTA images. Analysis of 3 × 3-mm scans yielded a mean FAZ area of 0.270 ± 0.101 mm2. The average reduction in vessel density per year of age with 3 × 3-mm OCTA scans was 0.04 mm-1 (0.22%) in the SCP, 0.05 mm-1 (0.27%) in the ICP, and 0.06 mm-1 (0.30%) in the DCP. The average increase in FAZ area per year of age was 0.0015 mm2 (0.72%). Conclusions Novel PAR software may provide improved visualization of all three major parafoveal retinal capillary plexuses including the ICP. Using this technology, SCP, ICP, and DCP vessel density decreased with increasing age while FAZ area increased with age.