Association between intraocular pressure and climate parameters

This study investigated the association between climate parameters and intraocular pressure (IOP). We used two large, multicenter cross-sectional datasets: the Japan Ningen Dock Study (JNDS), with 1,477,066 participants (52.3 ± 10.8 years), and the Jikei dataset, with 10,361 participants (50.3 ± 11.0 years). In both, IOP was measured via noncontact tonometry. We obtained daily average air temperature, station-level air pressure, and relative humidity from the Japan Meteorological Agency. We used multiple linear regression, adjusting for known IOP-related factors, to evaluate the relationship between climate parameters and IOP; the same analysis was also performed by prefecture as a sensitivity analysis. The mean right-eye IOP was 13.4 ± 3.0 mmHg (JNDS) and 12.7 ± 2.8 mmHg (Jikei). Air temperature showed a significant negative correlation with IOP (JNDS: β = - 0.032, 95% CI: - 0.033 to - 0.032, P < 0.001; Jikei: β = - 0.023, 95% CI: - 0.031 to - 0.016, P < 0.001), whereas neither air pressure nor humidity was associated with IOP. Sensitivity analysis indicated a stronger, though not significant, relationship between IOP and temperature in colder regions (correlation coefficient R = - 0.21, P = 0.174). These findings underscore the importance of considering climate, particularly temperature, in IOP fluctuations.