Relationship between intraocular pressure and pulmonary function

We aimed to investigate the association between respiratory function and intraocular pressure (IOP). We included the Jikei and Japan Ningen Dock Study (JNDS) datasets that included data from 10,361 (50.3 ± 11.0 years) and 283,199 (51.7 ± 10.3 years) participants, respectively. IOP was measured using non-contact tonometry, and respiratory function was assessed using spirometry, focusing on the forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio, percent predicted values of FEV1 (ppFEV1), and percent predicted values of FVC (ppFVC). The relationship between respiratory function indices and IOP was assessed using multiple linear regression. The mean IOP was 12.7 ± 2.8 and 13.3 ± 2.9 mmHg in the Jikei and JNDS datasets, respectively, with a significant positive linear correlation between FEV1/FVC and IOP (β = 0.020, 95% confidence interval [CI]: 0.011 - 0.029, P < 0.001 in the Jikei dataset; β = 0.015, 95% CI: 0.013 - 0.016, P < 0.001 in the JNDS dataset). Compared with healthy individuals, 505 and 2,228 participants with FEV1/FVC < 70% (Jikei dataset) and FEV1/FVC < 60% (JNDS dataset) had lower IOPs of 0.641 (95% CI: 0.286 - 0.996, P < 0.001) mmHg and 0.888 (95% CI: 0.729 - 1.047, P < 0.001) mmHg, respectively. Both ppFEV1 and ppFVC showed no association with IOP. This possible association between obstructive ventilatory disorders and IOP suggests the importance of considering respiratory function in IOP management.