Correlation between optic nerve head parameters and retinal nerve fibre layer thickness measured by spectral-domain optical coherence tomography in myopic eyes

Background: To evaluate the correlation between optic nerve head parameters and retinal nerve fiber layer thickness measured by Cirrus HD spectral-domain optical coherence tomography (Cirrus HD-OCT; Carl Zeiss Meditec) in healthy myopic eyes. Design: Cross-sectional study. Participants: One hundred and sixty-one right eyes from 161 healthy young myopic subjects. Methods: Optic nerve head parameters and retinal nerve fiber layer thickness were measured with the Cirrus HD-OCT. The distance between optic disc margin and scan circle (disc margin-to-scan distance) was measured on the Cirrus HD-OCT en-face optic nerve head image with aid of National Institutes of Health ImageJ image-analysis software (developed by Wayne Rasbands, National Institutes of Health, Bethesda, MD). Main Outcome Measures: The correlations among optic nerve head parameters, retinal nerve fibre layer thickness and the disc margin-to-scan distance were evaluated with and without adjustment of the magnification effect. Results: Without correction of the magnification effect, the thicker average retinal nerve fiber layer was correlated with greater rim area and lower degree of myopia (P < 0.001). When the magnification effect was corrected, thicker average retinal nerve fibre layer was associated with greater disc area and greater rim area in univariate and multivariate analyses (P = 0.028); however, degrees of myopia and the disc margin-to-scan distance were not significantly associated with average RNFL thickness (P = 0.104). Conclusions: Thicker average retinal nerve fibre layer thickness was associated with greater rim and disc areas. Disc margin-to-scan distance was not significantly correlated with average retinal nerve fibre layer thickness in healthy myopic eyes.