Ingestion of caffeine significantly increases intraocular pressure in patients with glaucoma or ocular hypertension—but seems to have no effect on patients with normal IOP, according to a study published in the August 13 online edition of Graefe’s Archive of Clinical and Experimental Ophthalmology.

In this systematic review and meta-analysis, the researchers performed a comprehensive literature search to identify a collection of six pertinent randomized controlled trials of 144 participants. Among the participants, 103 had normal pressures and 41 had glaucoma or ocular hypertension. All participants’ IOPs were measured at 30 minutes, 60 minutes and 90 minutes after caffeine consumption.

Intraocular pressure increased at each measurement interval in participants with glaucoma or ocular hypertension. However, no increase in intraocular pressure was documented at any measurement interval in participants with normal pressure.

Li M, Wang M, Guo W, et al. The effect of caffeine on intraocular pressure: a systematic review and meta-analysis. Graefes Arch Clin Exp Ophthalmol. 2010 Aug 13. [Epub ahead of print]