Analysis of the correlation between peripapillary retinal nerve fiber layer cross-sectional area and myopia in individuals aged 50 years and above

Abstract

Objective: To measure the peripapillary retinal nerve fiber layer (RNFL) cross-sectional area in individuals aged 50 years and above with different refractive errors, and analyze its correlation with axial length and refractive error. Methods: This was a cross-sectional study conducted as part of the "Beijing Eye Study". The study was population-based and longitudinally designed. In 2001, a cohort of individuals aged 40 years and above from five urban communities in Haidian District and three rural communities in Daxing District, Beijing, were surveyed. Follow-up examinations were conducted in 2011. In this study, the follow-up data from 2011 were collected and analyzed. One eye of each participant was randomly selected, and the participants were categorized into four groups based on their spherical equivalent: emmetropia group (-0.50 D≤spherical equivalent≤0.50 D), low myopia group (-3.00 D≤spherical equivalent<-0.50 D), moderate myopia group (-6.00 D≤spherical equivalent<-3.00 D), and high myopia group (spherical equivalent<-6.00 D). Spectral-domain optical coherence tomography (OCT) was used to perform circular scans with a diameter of 12° centered on the optic disc. ImageJ software and Heidelberg Eye Explorer software were used to calculate the RNFL cross-sectional area. One-way analysis of variance was used to compare the differences in RNFL thickness and RNFL cross-sectional area among different groups. Linear regression analysis was performed to analyze the correlation between RNFL thickness and axial length and spherical equivalent, as well as the correlation between RNFL cross-sectional area and axial length and spherical equivalent. Results: A total of 184 participants (184 eyes) were included in the study, including 88 males and 96 females. The median age was 59 (54, 66) years, with 87 right eyes and 97 left eyes. There were 50 participants (50 eyes) in the emmetropia group, low myopia group, and moderate myopia group, and 34 participants (34 eyes) in the high myopia group. There were no significant differences in age, gender, and eye laterality among the groups (all P>0.05). The RNFL cross-sectional areas in the emmetropia, low myopia, moderate myopia, and high myopia groups were (1.115±0.106), (1.122±0.136), (1.105±0.105), and (1.096±0.106) mm2, respectively, with no significant differences observed (F=0.43, P=0.730). The RNFL thickness in the emmetropia, low myopia, moderate myopia, and high myopia groups were (102.5±9.5), (102.5±12.1), (94.2±8.3), and (90.2±8.9) μm, respectively, with a significant difference observed (F=16.42, P<0.001). Univariate linear regression analysis was performed with spherical equivalent as the independent variable and peripapillary RNFL thickness as the dependent variable, yielding the regression equation: peripapillary RNFL thickness=102.651+1.634 × spherical equivalent (R2=0.21, P<0.001). Similarly, when axial length was used as the independent variable and peripapillary RNFL thickness as the dependent variable, the regression equation was: peripapillary RNFL thickness=174.161-3.147 × axial length (R2=0.18, P<0.001). There was no significant correlation between RNFL cross-sectional area and spherical equivalent (P=0.065) or axial length (P=0.846). Conclusions: There were no significant differences in peripapillary RNFL cross-sectional area among individuals aged 50 years and above with different axial lengths or refractive errors.