The Effect of Caffeine on Retrobulbar Hemodynamics

Abstract

The vascular resistance of the retrobulbar vessels appears to be altered by caffeine consumption. Further studies are needed to investigate the effects of caffeine on hemodynamics in patients with glaucoma.

Effects of caffeinated coffee consumption on intraocular pressure, ocular perfusion pressure, and ocular pulse amplitude: a randomized controlled trial

“…It is also the first trial to examine OPA after caffeine consumption. Other strengths include the wider 40-89-year-old age range and older 64-year-old mean age of our subjects, compared with the 20-44-year-old age range and approximately 25 year mean age of subjects in the other trials combined, 25,28,29,33,34,37 as the risk of POAG increases after age 40. The study's crossover design minimized individual variations, enhancing its power.…”

“…The study's crossover design minimized individual variations, enhancing its power. Unlike other RCTs, we did not exclude subjects on antiglaucoma medications, 25,28,29,31,33,34 on systemic medications, 25,31 with a history of cataract surgery or glaucoma laser procedure before the 6 months preceding the study, 25,28,[31][32][33][34] with systemic hypertension, 25,29,31,34 with diabetes, 25,29 who currently smoke, 29,33 who have a family history of glaucoma 33,34 and who ingest beyond a certain daily level of caffeine. 25, 29 The absence of these exclusions enhanced the generalizability of our results.…”

“…24 Advice regarding caffeine consumption varies because of controversy regarding the degree to which acute caffeine intake influences IOP levels. Several studies found IOP changes to be negligible, [25][26][27][28][29][30] whereas others report increases of approximately 1-4 mm Hg. [31][32][33][34][35][36] A recent meta-analysis 37 called for more high-quality randomized clinical trials (RCTs) to better assess caffeine's effects on IOP in those with or at risk for glaucoma and in older subjects.…”

“…[31][32][33][34][35][36] A recent meta-analysis 37 called for more high-quality randomized clinical trials (RCTs) to better assess caffeine's effects on IOP in those with or at risk for glaucoma and in older subjects. Most RCTs investigating caffeine intake and IOP have examined healthy subjects 25,28,29,33,34 with a mean age of 25 years. 37 Only two RCTs 31,32 have enrolled glaucoma and glaucoma suspect patients, and neither disclosed the subjects' ages.…”

A Vascular Approach to Glaucoma

“…Caffeine is a xanthine with known cardiovascular effects, such as increasing heart rate and increasing peripheral resistance by vasoconstriction (Bunker, 1979). A placebo-controlled trial in healthy individuals showed that the resistance index of ophthalmic; short posterior ciliary arteries and central retinal arteries were significantly increased after coffee ingestion (Ozkan, 2008). Despite its concomitant ability to mildly increasing IOP, a prospective study did not find an increased risk for primary open-angle glaucoma in average coffee drinkers (people consuming more than 5 cups a day had a small risk increase) (Kang, 2008).…”