To assess the effect of age and gender on intraocular pressure (IOP) in a large Korean population.

This cross-sectional study included 102,218 healthy Koreans who were aged between 20 and 79 and had no preexisting ocular conditions that could affect the IOP. All the subjects had undergone a physical check up between 1996 and 2005, and their medical records were reviewed retrospectively. Anthropometric measurements, blood tests, noncontact tonometry, and fundus examination were performed on all participants. Subjects were grouped according to decade of age. For all subjects and each age group, age and systemic variables were analyzed by multiple regression analysis on their relationship with IOP.

A significant trend of decreasing IOP was observed in the 40s, 50s, and 60s in men, while a significant trend of increasing IOP was found in the 50s, 60s, and 70s in women. Multiple regression analysis revealed different IOP trends with age between age groups in both men and women. In general, the IOP had a significant positive correlation with systolic blood pressure, body-mass index (BMI), hematocrit, and serum cholesterol, especially with BMI in men and hematocrit in women.

In a multiple regression analysis, the IOP trend in each age group was quite different from each other in a large Korean population, and it was suggested that women may have a steeper increasing slope (or less steep decreasing slope) of IOP with age than men. Further investigations with longitudinal study would be required to clarify the age- and gender-related physiologic changes of IOP.