Diagnostic discrepancies in glaucoma: underdiagnosis, overdiagnosis and missed opportunities in a nationwide South Korean population.

Abstract

To investigate glaucoma prevalence and diagnostic discrepancies-undiagnosed glaucoma, missed diagnostic opportunities and false-positive diagnoses-in South Korea and to identify factors contributing to these errors. This nationwide cross-sectional study used data from the Korea National Health and Nutrition Examination Survey 2019-2021. Participants aged ≥20 years who had gradable ophthalmic examinations were included. Glaucoma was adjudicated by specialists using International Society of Geographical and Epidemiological Ophthalmology criteria. Survey-weighted logistic regression analyses were performed to identify factors associated with undiagnosed glaucoma and missed diagnostic opportunities. The final analytical cohort comprised 18 710 participants. The weighted prevalence of glaucoma was 3.9% (95% CI 3.6% to 4.2%). The awareness rate was only 17.1%, leaving 82.9% (95% CI 80.4% to 85.4%) of cases undiagnosed. Notably, 44.7% (95% CI 41.0% to 48.3%) of undiagnosed cases represented a missed diagnostic opportunity. Multivariable analysis identified high myopia as the strongest predictor of a missed diagnostic opportunity (OR 23.53, 95% CI 5.65 to 98.09, p<0.001), alongside younger age (OR 0.98, p=0.039), rural residence (OR 1.97, p=0.047) and thicker retinal nerve fibre layer (OR 1.09, p<0.001). The lowest household income quartile was associated with undiagnosed glaucoma (OR 1.87, p=0.019). Diagnostic discrepancies present a dual burden: profound underdiagnosis coexists with frequent false-positive diagnosis. High myopia, milder disease phenotype and rural residence are central drivers of missed diagnostic opportunities. Reducing discrepancies will therefore require efforts at both the clinical-professional and health system levels.