Abstract
Purpose :
To investigate the association between circumpapillary retinal nerve fiber layer (cRNFL) thickness and optic disc characteristics with sectoral radial peripapillary capillary (RPC) density using optical coherence tomography (OCT) angiography.
Methods :
34 healthy participants underwent 6×6-mm scans centered on the optic disc using a commercially available 68-kHz spectral OCT angiography system (Cirrus 5000 with AngioPlex; Carl Zeiss Meditec). En face RPC angiograms generated with a semiautomated segmentation method were analyzed quantitatively for RPC density in 8 equally divided sectors (IN, inferior nasal; IT, inferior temporal; NL, nasal lower; NU, nasal upper; SN, superior nasal; ST, superior temporal; TL, temporal lower; TU, temporal upper) within a ring of 4.5-mm outer and 2.25-mm inner diameters. Large vessels were masked and excluded from the analysis. Structural OCT scans were used to analyze horizontal and vertical optic disc tilt and provided sectoral cRNFL thickness, rim area, cup volume, and vertical and average cup-disc (C/D) ratio. Association of RPC density, cRNFL, optic disc characteristics, and axial length was explored using bivariate plots and correlation and multivariate regression analyses.
Results :
Reduced RPC density in the nasal sectors (NL, IN, SN, NU) were significantly associated with thinner cRNFL thickness in the corresponding sectors. Reduced rim area and longer axial length were associated with reduced nasal RPC density (P < 0.01). Horizontal disc tilt was associated with decreased RPC density in IT, NL, and NU sectors (all P < 0.05). Temporal RPC density did not correlate with corresponding cRNFL sectors. Vertical disc tilt, cup volume, and average and vertical C/D ratio were not associated with RPC density in healthy eyes.
Conclusions :
Significant reduction in nasal RPC density was seen with cRNFL decrease, horizontal optic disc tilt, and longer axial length. These factors may be important considerations when determining the regional susceptibilities reflecting damage to tissues relevant to the pathophysiology of optic neuropathies.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.