PURPOSE: To investigate the associations of lung function with glaucoma and related traits, explore the interactions between glaucoma genetic risk and lung function, and assess the causal relationships using Mendelian randomization (MR). METHODS: This cross-sectional study involved 85,369 participants with lung function measurements at baseline from the UK Biobank. Associations between lung function parameters and glaucoma and related traits were tested by multivariable logistic and linear regression. Two-sample MR analyses were conducted using summary statistics from large genetic datasets. RESULTS: Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), and FEV1/FVC ratio were inversely associated with glaucoma, with the lowest quartiles conferring odds ratios (ORs) of 1.51 (95% confidence interval [CI], 1.31-1.74
P = 7.6 × 10-8), 1.58 (95% CI, 1.37-1.81
P = 4.7 × 10-10) and 1.20 (95% CI, 1.08-1.34
P = 0.002), respectively, compared with the highest quartiles (P trends <
0.001 observed for each). Similar associations were found for impaired lung function (FEV1 <
80% Global Lung Initiative predicted FEV1: OR, 1.22, 95% CI, 1.11-1.33
P = 1.2 × 10-5
FEV1/FVC <
0.7: OR, 1.13, 95% CI, 1.03-1.24
P = 0.01). Lower lung function was associated with lower intraocular pressure (IOP), thinner macular retinal nerve fiber layer thickness, and thinner ganglion cell-inner plexiform layer thickness. No interactions were observed between glaucoma genetic risk and lung function. MR analyses did not suggest causal relationships. CONCLUSIONS: Lower FVC, FEV1, FEV1/FVC, and impaired lung function are potential biomarkers for glaucoma risk. These findings may facilitate clinical strategies for glaucoma management, particularly for individuals with impaired lung function.