Purpose:
To investigate the effect of intravenous nebivolol (ß1 antagonist and nitric oxide mediated vasodilator) on choroidal and ciliary blood flow regulation in rabbits
Methods:
Mean arterial pressure (MAP), intraocular pressure (IOP) and orbital venous pressure (OVP) were measured by direct cannulation of the central ear artery, the vitreous, and the orbital venous sinus, respectively. Laser Doppler flowmetry was used to measure choroidal blood flow and ciliary blood flow simultaneously while MAP was manipulated mechanically with occluders on the aorta and vena cava, thus changing ocular perfusion pressure (PP) over a wide range. Pressure-flow (PF) relationships were performed at control and in response to i.v. bolus injection.
Results:
In addition to the baseline changes nebivolol caused a significant downward shift of the choroidal pressure flow relationship.
Conclusions:
Nebivolol is a choroidal vasoconstrictor in addition to its lowering effect on IOP, hear rate. The effects on ciliary blood flow and OVP were not significant.
Keywords: choroid • ciliary body • blood supply