Correlations Between Retinal Nerve Fiber Layer Thickness and Axial Length, Peripapillary Retinal Tilt, Optic Disc Size, and Retinal Artery Position in Healthy Eyes.

PURPOSE: To determine the correlations between the retinal nerve fiber layer thickness (RNFLT) and the axial length, peripapillary retinal tilt (PRT), and optic disc size, and retinal artery position.

METHODS: A prospective, observational cross-sectional study of 119 healthy right eyes of 119 volunteers. All participants underwent comprehensive ophthalmologic examinations including peripapillary RNFLT imaging and measurements of the axial length. The RNFLT was determined by the TOPCON 3D OCT-1000, MARK II. The RNFLT in a 3.4 mm circular scan was divided into 12 clock-hour sectors and 4 quadrant sectors around the optic disc. The PRT was assessed using the RNFLT B-scan images. The angle between the supra-temporal and infra-temporal retinal arteries was determined in the color fundus photographs. The correlations between the sectorial RNFLTs and the axial length, PRT, optic disc size, and artery angles were determined by simple and multiple regression analyses.

RESULTS: Multiple regression analyses showed that the nasal and inferior quadrants and the whole RNFLT were significantly and negatively correlated with the axial length (standardized coefficient (SC)=-0.39 to -0.30, P<0.05). The PRT was significantly and positively associated with all of the quadrants and the whole RNFLT (SC=0.22 to 0.45, P<0.05). The retinal artery angle was significantly and negatively associated with the temporal RNFLT and positively associated with inferior RNFLT (SC=-0.49 to 0.31, P<0.05). The optic disc size was significantly and positively associated with the superior and nasal quadrants, and the whole RNFLT (SC=0.20 to 0.27, P<0.05).

CONCLUSIONS: The axial length, PRT, optic disc size, retinal artery angle can affect the peripapillary RNFLT. These variables should be considered when assessing the peripapillary RNFLT.