Objective: To investigate the association between cardiorespiratory fitness and mean corrected intraocular pressure (IOP) in a normotensive health check-up population, and to evaluate potential differences across age and sex strata.
Methods: This cross-sectional study consecutively enrolled adults aged 18-70 years who completed cardiorespiratory fitness testing and ophthalmologic examinations at the Health Management Center of Sichuan Provincial People's Hospital between July 1, 2019 and December 31, 2025. Individuals were excluded if they had a history of glaucoma, ocular diseases interfering with IOP measurement, systemic diseases or medications affecting IOP, contraindications to fitness testing, or abnormal blood pressure. A final sample of 2,921 normotensive individuals was included. Cardiorespiratory fitness was assessed by estimated maximal oxygen uptake (VO₂max). After age- and sex-stratified grouping, low cardiorespiratory fitness was used as the reference, and the remainder were defined as the moderate-to-high cardiorespiratory fitness group. The primary outcome was the mean corrected IOP of both eyes. Multiple imputation, multivariable linear regression, and age- and sex-stratified analyses were used to evaluate the association.