Association between localized retinal nerve fiber layer defects in nonglaucomatous eyes and metabolic syndrome: a propensity score-matched analysis

BACKGROUND: We investigated the association between metabolic syndrome and localized retinal nerve fiber layer (RNFL) defects in nonglaucomatous subjects. METHODS: We examined 20,385 adults who visited the Health Promotion Center of Seoul St. Mary’s Hospital between May 2015 and April 2016. After excluding those with known glaucoma or glaucomatous optic discs, subjects with and without localized RNFL defects were 1:5 propensity score matched. Metabolic syndrome components, including central obesity, elevated triglyceride, reduced high-density lipoprotein (HDL) cholesterol, elevated blood pressure (BP), and elevated fasting glucose, were compared between two groups. We performed logistic regression to investigate the association between RNFL defects and each component of metabolic syndrome and the number of metabolic syndrome components. RESULTS: Subjects with RNFL defects showed higher waist-to-hip ratios, systolic BP (SBP) and diastolic BP (DBP), fasting blood glucose, and hemoglobin A1c (HbA1c) levels than did those without RNFL defects both before and after propensity score matching. The number of metabolic syndrome components was significantly greater in those with RNFL defects (1.66±1.35) than in those without (1.27±1.32, P<0.01). In multivariate logistic regression, the odds ratio (OR) of RNFL defects was significantly increased in subjects with central obesity [OR =1.53, 95% confidence interval (CI): 1.11–2.13], elevated BP (OR =1.50, 95% CI: 1.09–2.05), and an elevated fasting glucose level (OR =1.42, 95% CI: 1.03–1.97). An increased number of metabolic syndrome components was associated with a higher risk of RNFL defects. CONCLUSIONS: Localized RNFL defects in nonglaucomatous subjects are associated with metabolic syndrome components, including central obesity, elevated BP, and an elevated fasting glucose level, suggesting that comorbid metabolic syndrome should be considered when evaluating subjects with RNFL defects.