title: Effect of coffee consumption on intraocular pressure.
abstract: BACKGROUND
  Many ophthalmologists instruct patients with glaucoma to avoid coffee, although data supporting this practice are insufficient.
  
  
  OBJECTIVE
  To estimate the effect of drinking coffee on intraocular pressure (IOP).
  
  
  METHODS
  In this crossover study, the effect of the consumption of regular (180 mg caffeine in 200 mL beverage) and decaffeinated coffee (3.6 mg caffeine in 200 mL beverage) was compared in patients with normotensive glaucoma (n = 6) or ocular hypertension (n = 22). IOP was monitored in both groups at 30, 60, and 90 minutes after coffee ingestion.
  
  
  RESULTS
  In patients with normotensive glaucoma who drank regular coffee, the mean +/- SD changes in IOP at 30, 60, and 90 minutes were 0.9 +/- 0.5, 3.6 +/- 1.1, and 2.3 +/- 0.66 mm Hg, respectively; in those who drank decaffeinated coffee, they were 0.75 +/- 0.36, 0.70 +/- 0.4, and 0.4 +/- 0.6 mm Hg, respectively. The corresponding values in patients with ocular hypertension were as follows: after regular coffee, 1.1 +/- 0.7, 3.4 +/- 1.0, and 3.0 +/- 2.7 mm Hg; and after decaffeinated coffee, 0.6 +/- 0.4, 0.9 +/- 0.2, and 0.5 +/- 0.5 mm Hg. The difference in the change in IOP from baseline after ingestion of regular versus decaffeinated coffee was statistically significant in each group at 60 and 90 minutes. Subjects who drank regular coffee demonstrated a greater elevation in IOP; this elevation may be clinically significant.
  
  
  CONCLUSIONS
  Intake of caffeinated beverage (>/=180 mg caffeine) may not be recommended for patients with normotensive glaucoma or ocular hypertension.
authors.affiliation: Department of Ophthalmology and External Eye Disease Clinic, Rabin Medical Center, Petah Tiqva, Israel. lavisar@bezeqint.net.
authors.forename: Rahamim
authors.initials: R
authors.lastname: Avisar
authors.forename: Erez
authors.initials: E
authors.lastname: Avisar
authors.forename: Dov
authors.initials: D
authors.lastname: Weinberger
mesh_terms: D001794:Blood Pressure / Q000187:drug effects; D002110:Caffeine / Q000009:adverse effects*; D003069:Coffee / Q000009:adverse effects*; D000075202:Contraindications; D018592:Cross-Over Studies; D005260:Female; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D013997:Time Factors
chemical_list: D003069:Coffee; D002110:Caffeine