AIM:To assess the effect of myopia on the thickness of retinal nerve fiber layer (RNFL) measured by 3D optical coherence tomography (3D-OCT) in a group of nonglaucomatous Chinese subjects.METHODS:Two hundred and fifty-eight eyes of 258 healthy Chinese myopic individuals were recruited and four groups were classified according to their spherical equivalent (SE):low myopia (n=42, -0.5D<SE<-3.0D), moderate myopia (n=120, -3.0D≤SE<-6.0D), high myopia (n=58, -6.0D≤SE<-8.0D) and extreme high myopia (n=38, SE≥-8.0D). The RNFL thickness profile including superior, nasal, inferior and temporal quadrant and each of the 12 clock-hour thicknesses were measured by 3D-OCT. The RNFL thicknesses among four sample groups were performed by one-way analysis of variance (one-way ANOVA) and least significant difference test (LSD test). Correlations between RNFL thickness and axial length/spherical equivalent were performed by linear regression analysis.RESULTS: The overall RNFL parameters shown significant differences between groups excluding 7, 9, 10, 11 o’clock hour thickness. The RNFL thickness of superior, nasal, inferior, average and 1, 2, 3, 4, 5, 6, 12 o’clock sectors were decreased with the increasing axial length and higher degree of myopia. In contrast, as axial length and the degree of myopia increased, the temporal and 8, 9 o’clock sectors thicknesses were increased. A considerable proportion of myopic eyes were classified as outside the normal limits. Six o’clock was the most notable of the total, which 43.4% were outside the normal limits.CONCLUSION:On the measurement of RNFL, the characteristics of RNFL with the change of the degree of myopia were observed. As the degree of myopia increases, the RNFL thickness measured by 3D-OCT including the average and superior, nasal, inferior sectors decreases. And due to the change of RNFL thickness, it should be considered when using OCT to access for the damage of glaucoma especially people with myopia.