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Naim Terai, Eberhard Spoerl, Richard P. Stodtmeister, Lutz E. Pillunat; Caffeine Affects Ocular Microcirculation In Young Healthy Subjects. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6849.
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© ARVO (1962-2015); The Authors (2016-present)
To investigate the effect of caffeine on ocular microcirculation in young healthy subjects
Seventeen healthy subjects were included in this study.The diameter of retinal vessels was measured continuously with the dynamic vessel analyzer (DVA) before and 1 hour after 200 mg caffeine intake. After baseline assessment a monochromatic luminance flicker was applied to evoke retinal vasodilatation. Flicker response was then analyzed 50, 150 and 250 sec after baseline measurement. Additionally, blood pressure parameters and intraocular pressure (IOP) were obtained before and after caffeine intake.
The mean diameter of the arterioles at baseline before caffeine intake was 123.30 ± 14.0 µm and after caffeine 117.30 ± 13.0 µm which was significantly different (P=.004) before and after treatment. The mean diameter of the venules at baseline before caffeine intake was 147.60 ± 19.5 µm and after caffeine 137.73 ± 19.9 µm which was significantly different (P=.005.). The flicker-induced increase in vasodilatation from baseline measurement in the arterioles was 3.4 ± 2.3 µm before and 4.3 ± 2.5 after caffeine consumption (P=.020). The flicker-induced increase in vasodilatation in the venules was 4.3 ± 3.4 µm before and 7.4 ± 2.6 after caffeine consumption from baseline measurement (P=.0001). The flicker response of the arterioles (defined as FR=100 x (flicker-baseline)/flicker %) increased from 2.8 % before caffeine to 3.8 % after caffeine intake (P=.010). The flicker response of the venules increased from 3.4 % before caffeine to 5.5 % after caffeine intake (P=.0001). Systolic blood pressure changed from 126.5 ± 11.0 mmHg to 135.3 ± 13.2 mmHg after caffeine (P=.001). Diastolic blood pressure increased from 83.3 ± 8.4 mmHg to 88.2 ± 10.5 mmHg after caffeine intake (P=.010). Pulse rate decreased from 77.2 ± 10.5 bpm to 68.4 ± 12.3 bpm (P=.010). IOP changed from 12.5 ± 2.8 mmHg to 12.9 ± 2.5 mmHg after caffeine which was without statistical significance (P=.387)
The present study showed a significant vasoconstrictory response of the retinal arterioles and venules 1 hour after caffeine intake in young healthy subjects measured by the DVA. Also the reacting capacity of the arterioles and the venules showed a significant improvement before and after caffeine consumption. These effects might be elicited by the inhibitory effect of caffeine on adenosine, a potent vasodilatator of the retinal vasculature.
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