Effects of dopamine on retinal and choroidal blood flow parameters in humans

Aim: To investigate the effect of dopamine on retinal and choroidal blood flow in humans Methods: In a randomized double-masked cross-over study in 12 of 16 healthy subjects we investigated the effect of two doses of intravenous dopamine (5 and 10 μg.kg-1min-1). Blood flow parameters in retina, optic nerve head and choroid were assessed with bi-directional laser Doppler velocimetry, laser Doppler flowmetry and laser interferometric measurement of fundus pulsation amplitude, respectively. Results: Intravenous dopamine dose-dependently increased retinal blood cell velocity and fundus pulsation amplitude (p < 0.001). At the highest administered dose red blood cell velocity in retinal vessels increased by 37% and fundus pulsation amplitude by 24%. In contrast optic nerve head blood flow did not change with dopamine administration. Conclusions: Our data indicate that dopamine has a pronounced enhancing effect on the retinal perfusion in humans. Further studies are required to establish the exact role of dopamine in the regulation of choroidal and optic nerve head blood flow.