Japanese Journal of Ophthalmology · Oct 17, 2026
Subfoveal choroidal thickness across age and sex in a Korean population: insights from KNHANES 2017-2021
By Kim HM, Nam S, Kim MS
PURPOSE: To establish a nationally representative normative reference dataset for subfoveal choroidal thickness (SFCT) in healthy eyes and to provide practical operational tools for interpreting individual SFCT measurements in clinical settings. STUDY DESIGN: Population-based cross-sectional study. METHODS: We utilized data from participants in the Korea National Health and Nutrition Examination Survey 2017-2021 who underwent comprehensive ophthalmic examinations including SFCT measurements. Survey-weighted multivariable linear regression models were constructed to assess associations, with additional age- and sex-stratified analyses performed. RESULTS: The normative reference cohort enrolled 27,965 participants. SFCT demonstrated a significant linear decrease with advancing age in OU (OD: β=-2.00, SE=0.12, P<0.001; OS: β=-1.84, SE=0.15, P<0.001) in multivariate models. Significant sex differences were observed in participants aged 30-39 years (OD: difference, -31.8 μm; 95% CI -48.6 to -15.0; P<0.001; OS: difference, -33.1 μm; 95% CI -51.1 to -15.1; P<0.001) and 40-49 years (OD: difference, -27.8 μm; 95% CI -33.6 to -22.1; P<0.001; OS: difference, -28.6 μm; 95% CI -34.8 to -22.4; P<0.001), and this difference diminished in older age groups. CONCLUSIONS: This study establishes a comprehensive normative reference framework for SFCT utilizing a nationally representative Korean population. These data may serve as reference values for evaluating choroidal structural changes in retinal and choroidal diseases.