Superficial capillary plexus vessel density/deep capillary plexus vessel density ratio in healthy eyes

BACKGROUND: To identify factors differently affecting the superficial capillary plexus (SCP) and deep capillary plexus (DCP) in healthy eyes using their vessel density (VD) ratio. METHODS: Healthy eyes were enrolled. The ratio between the VD of SCP and DCP (SVD/DVD ratio) was calculated. Pearson correlation analyses were performed to identify the relationships between this ratio and other factors. RESULTS: The mean SVD and DVD were 36.2 ± 5.7 and 37.7 ± 4.9%, respectively, and the mean SVD/DVD ratio was 0.96 ± 0.15. The SVD was significantly correlated with the best-corrected visual acuity (BCVA) (r = − 0.368, P < 0.001), age (r = − 0.408, P < 0.001), and OCTA quality (r = 0.520, P < 0.001). The DVD was significantly correlated with the BCVA (r = − 0.150, P = 0.008), age (r = − 0.229, P < 0.001), and OCTA quality (r = 0.555, P < 0.001). Among various factors, age (r = − 0.296, P < 0.001), the BCVA (r = − 0.237, P < 0.001), axial length (r = 0.234, P < 0.001), and OCTA quality (r = 0.270, P < 0.001) were significantly correlated with the SVD/DVD ratio. CONCLUSIONS: Age, BCVA, axial length, and OCTA image quality were significantly correlated with the SVD/DVD ratio. Age, the BCVA, and OCTA quality were more strongly correlated with the SCP, and the axial length was more strongly correlated with the DCP.