title: Effects of caffeine on intraocular pressure: the Blue Mountains Eye Study.
abstract: OBJECTIVE
  To examine the relationship between coffee and caffeine intakes and intraocular pressure (IOP).
  
  
  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 > or = 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.
authors.affiliation: Centre for Vision Research, Department of Ophthalmology and the Westmead Millennium Institute, the University of Sydney, Australia.
authors.forename: Sujatha
authors.initials: S
authors.lastname: Chandrasekaran
authors.forename: Elena
authors.initials: E
authors.lastname: Rochtchina
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
mesh_terms: D001794:Blood Pressure; D002110:Caffeine / Q000009:adverse effects*; D003069:Coffee / Q000009:adverse effects; D005260:Female; D005902:Glaucoma, Open-Angle / Q000150:complications; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D008875:Middle Aged; D009517:New South Wales; D009798:Ocular Hypertension / Q000150:complications; D011795:Surveys and Questionnaires; D013662:Tea / Q000009:adverse effects; D014065:Tonometry, Ocular; D058609:Visual Field Tests
chemical_list: D003069:Coffee; D013662:Tea; D002110:Caffeine