Abstract
PURPOSE: Little is known about the effects of ambient atmospheric pressure (AP) on intraocular pressure (IOP) under ordinary conditions. This study aimed to investigate the effects of AP on Goldmann applanation tonometer-measured IOP (GAT-IOP) in normal eyes under everyday atmospheric conditions adjusting for effects of possible confounding factors including other climatic factors. METHODS: Data obtained from 2,431 normal healthy eyes of 2,431 subjects (mean age: 56.9 years) who participated in this population-based glaucoma survey in Japan were analyzed via multivariable linear regression analysis, where the GAT-IOP was the response variable; explanatory variables were the ocular and systemic factors and calendar factors reportedly correlated with GAT-IOP as well as AP, relative humidity, temperature, wind speed, and weather. The Bonferroni correction was adopted to obtain P values. RESULTS: Only AP of the outside air when each subject was examined was positively correlated with GAT-IOP (regression coefficient (RC) = 0.0460; P = 0.0051). Central corneal thickness, body mass index, and systolic blood pressure were positively correlated (RC = 0.0133, 0.0754, 0.0131; P < 0.0001, P < 0.0001, P = 0.0016, respectively), and corneal curvature radius and age were negatively correlated (RC=-0.7017, -0.0225; P = 0.0144, P = 0.0111, respectively) with GAT-IOP. The seasonal effect on GAT-IOP was also significant (P < 0.0001), and in reference to winter, summer was correlated with lower GAT-IOP and spring was correlated with higher GAT-IOP (RC=-0.5133, 0.4590; P = 0.0087, P = 0.0001, respectively). CONCLUSIONS: AP was found to have a significantly positive correlation with GAT-IOP in normal healthy eyes under ordinary conditions, though the actual impact of AP on IOP in normal individuals under ordinary conditions would be minimal.