Acute effects of coffee consumption on the microcirculation of macula and optic nerve head.

Purpose: This study aimed to evaluate the acute changes in retinal vasculature following coffee consumption. Methods: This is an interventional case series. The subjects were 22 healthy young adults. They were asked to rest in a silent room for 15 min; then, their heart rate, blood pressure, and arterial oxygen saturation pressure were measured with a single patient monitoring system. Optical coherence tomography (OCT) and OCT angiography (OCT-A) imaging of the disc and macula were performed for both eyes of the subjects. These measurements were repeated 45 min after drinking a cup of 450 ml of coffee containing a standard dose of 130 mg of caffeine. Macular and optic nerve head neurovasculature changes were assessed. Results: The results of our study did not show a significant change in peripapillary retinal nerve fiber layer thickness and neural structural and vascular parameters of the optic nerve head. Although assessments of macular vasculature showed a significant decrement in superficial ( p  = 0.01) and deep vessel density ( p  = 0.05) at parafovea, vessel densities (VDs) at the fovea, and deep capillary plexus at perifovea showed no significant change. Conclusion : Consuming one cup of coffee (150 mg caffeine) statistically changes central foveal thickness and parafoveal blood flow but likely does not have a clinical impact in healthy young adults.