Retinal nerve fiber bundle trajectories in Chinese myopic eyes: Comparison with a Caucasian based mathematical model

Previously we developed a mathematical model for describing the retinal nerve fiber bundle (RNFB) trajectories in the human retina. The model was based on Caucasian eyes that were not selected regarding refraction. The aim of this study was to determine the characteristics of the RNFB trajectories in Chinese myopic eyes. We collected high quality red free fundus images from 80 eyes of 80 Chinese myopic subjects (median [interquartile range/range] refraction -3.9 [-6.0 to -2.5/-10 to -1] D). We traced all visible RNFBs (n = 1460) and evaluated their trajectories using the previously published mathematical model. In the superior-temporal region, the RNFB trajectories of the Chinese myopic eyes were similar to that of the Caucasian eyes (86% of trajectories within the 95% central range of the Caucasian model). In the inferior-temporal region, the trajectories of the Chinese low to moderate myopic eyes were also similar to that of the Caucasian eyes (85%); trajectories of the high myopic eyes (spherical equivalent beyond -6.00 D) were clearly less curved (75%). Associations between individual deviations from the model and axial length, retinal vessel course, and optic disc anatomy were studied with multiple linear regression analysis. In the superior-temporal region, the trajectories were associated with retinal vessel course (P = 0.008) and optic disc size (P = 0.016). In the inferior-temporal region, there was a significant association with axial length (P < 0.001), retinal vessel course (P = 0.006), and disc torsion (P = 0.009).