AUTOREGULATION OF HUMAN OPTIC-NERVE HEAD BLOOD-FLOW

Background Autoregulation is defined as the maintenance of constant bl ood flow in a vascular system in spite of changes in perfusion pressur e (PPm). Materials and Methods PPm was decreased by increasing the int raocular pressure (IOP) with a suction cup and optic nerve blood flow was measured with the laser Doppler flowmetry technique (LDF) in 9 nor mal volunteers. Results The blood flow was autoregulated down to a PP, of 13 mm Hg (IOP = 47 mm Hg). Conclusions These results confirm previ ous studies in cats and monkeys. The mechanism of autoregulation is pr obably a decrease in resistance due to capillary recruitment.