Association between 7-year Changes in Intraocular Pressure and Systemic Factors in Koreans: A Longitudinal Study

ABSTRACT

PURPOSE: To investigate the changes in intraocular pressure (IOP) and associated systemic factors over 7 years in a healthy Korean population. METHODS: This longitudinal study included healthy subjects with no history of ocular disease and who had been receiving health examinations seven years apart at the Konkuk University Medical Center, Healthcare Center. The participants completed lifestyle questionnaires and underwent general health examinations (blood pressure, height and weight, and blood biochemical tests) and ocular examinations including noncontact tonometry and fundus photography. Subjects with abnormal fundus photography findings and ocular hypertension were excluded. Changes in IOP and systemic factors over 7 years were analyzed. RESULTS: Of 524 possible subjects, 469 were enrolled (55 subjects were excluded: 50 due to abnormal fundus photography and 5 for missing data). The left eye was analyzed in all patients. In all subjects, initial IOP (mean 14.50 ± 3.14 mmHg) was not significantly different from final IOP (14.72 ± 3.38 mmHg) (paired t-test, p = 0.074). In male patients, the final IOP was significantly higher than the initial IOP (paired t-test, p = 0.035). Lifestyle questionnaire variables were associated with a final IOP that was significantly higher than the initial IOP (smokers, alcohol drinkers and less exercisers, paired t-test; p = 0.014, 0.010 and 0.024, respectively). A linear mixed-effects model analysis showed that the change in IOP was negatively associated with age, but this was not statistically significant. Changes in systolic blood pressure (SBP), body mass index (BMI), total cholesterol (T.Chol) and low density lipoprotein (LDL) were positively correlated with change in IOP. CONCLUSIONS: A linear mixed-model analysis showed IOP decreased with age but this was not statistically significant. Changes in SBP, BMI, T.Chol and LDL were significantly positively correlated with change in IOP.