Effects of caffeine on intraocular pressure - The Blue Mountains Eye Study

Purpose: To examine the relationship between coffee and caffeine intakes and intraocular pressure (IOP). Materials and Methods: The Blue Mountains Eye Study examined 3654 participants aged 49+ years in an area west of Sydney, Australia. A detailed medical history questionnaire included average daily intakes of coffee and tea. The eye examination included Goldmann applanation tonometry and automated perimetry. Participants using glaucoma medications or who had previous cataract or glaucoma surgery or signs of pigmentary glaucoma/pigment dispersion, were excluded. Mean and maximum IOP calculations were used. Results: Participants with open-angle glaucoma (OAG) who reported regular coffee drinking had significantly higher mean IOP (19.63 mm Hg) than participants who said that they did not drink coffee (16.84 mm Hg), after multivariate adjustment, P = 0.03. Participants consuming >= 200 mg caffeine per day had higher mean IOP (19.47 mm Hg) than those consuming < 200 mg caffeine per day (17.11 mm Hg), after adjusting for age, sex, and systolic blood pressure (SBP), P = 0.06. This association did not reach statistical significance after multivariate adjustment. No association between coffee or caffeine consumption and higher IOP was found in participants with ocular hypertension (OH) and those without open-angle glaucoma. Conclusions: In participants with open-angle glaucoma, this study identified a positive cross-sectional association between coffee consumption/higher caffeine intakes and elevated intraocular pressure.