Distributions of Radial Peripapillary Capillary Density and Correlations with Retinal Nerve Fiber Layer Thickness in Normal Subjects

BACKGROUND: The aim of this study was to investigate distribution rules of radial peripapillary capillaries (RPCs) density and correlations with retinal nerve fiber layers (RNFL) thickness in normal subjects. MATERIAL/METHODS: We included 78 eyes of 78 healthy subjects examined by optical coherence tomography angiography (OCTA). RPCs density and RNFL thickness were measured automatically. Distributions of RPCs density and RNFL thickness were analyzed at different locations. Correlations of these 2 parameters and relationship with large vessels were evaluated by Spearman test. RESULTS: Average density for overall, peripapillary, and inside disc RCPs was 56.12±2.51%, 58.56±2.84%, and 60.16±4.01%, respectively. Overall and peripapillary RCPs density were positively correlated with RNFL thickness (r=0.595, P<0.0001; r=0.578, P<0.0001). The highest RCPs density was found in the temporal quadrant and was lowest nasally, whereas the RNFL thickness was found to be lowest temporally and higher in the nasal region. However, a positive correlation was found in each sector, which was highest in the temporal inferior (r=0.550, P<0.0001). Large vessels were insignificantly correlated with both RCPs density and RNFL thickness in sector analysis. CONCLUSIONS: Although the distributions of RPCs density and RNFL thickness were different, a positive correlation was found in each sector. Distribution rules of RPCs density and RNFL thickness were related to both vascular-structure and activity-vascular.