Axial length and glaucoma prevalence in a nationally representative Korean population

Background/aims To investigate the association between axial length (AXL) and survey-defined glaucoma prevalence, including operational open-angle glaucoma (OAG) and normal-tension glaucoma (NTG) in a nationally representative Korean population. Methods This cross-sectional, population-based study included 8202 participants aged ≥40 years from the Korea National Health and Nutrition Examination Survey 2019–2021 with available AXL and glaucoma assessment data. Participants were categorised by AXL as <24 mm, 24–<25 mm, 25–<26 mm or ≥26 mm. Survey-weighted prevalence and adjusted ORs for survey-defined glaucoma and operational OAG and NTG proxies were estimated using multivariable logistic regression. Supplementary analyses were performed using spherical equivalent-based myopia categories. Results Glaucoma prevalence was higher in participants with AXL ≥26 mm than in those with AXL <24 mm (12.6% vs 4.8%). In participants with AXL ≥26 mm, the prevalences of OAG and NTG proxies were 12.4% and 11.9%, respectively, within their corresponding observed-data domains. In fully adjusted analyses, compared with AXL <24 mm, AXL ≥26 mm was associated with higher odds of survey-defined glaucoma (OR, 5.91; 95% CI 3.88 to 9.01), the OAG proxy (OR, 8.70; 95% CI 5.08 to 14.89) and the NTG proxy (OR, 8.19; 95% CI 4.75 to 14.13). In descriptive sensitivity analyses, additional adjustment for treatment-corrected intraocular pressure did not materially attenuate the association with survey-defined glaucoma. Similar findings were observed in spherical equivalent-based analyses. Conclusion Longer AXL was associated with higher prevalence of survey-defined glaucoma in Korean adults, with similar patterns observed for operational OAG and NTG proxies.