Ophthalmic artery blood flow pattern and the pulsatile ocular blood volume changes in patients with hemodynamically significant carotid occlusive disease are described. Using transorbital Doppler ultrasonography and dynamic tonometry 45 patients with high-grade internal carotid artery stenosis or occlusion and 15 healthy controls were examined. The measurements were performed under baseline conditions and 30 min after 1 gi.v. acetazolamide administration. The velocity in the ophthalmic artery was significantly lower in patients compared with controls. Pulsatile ocular blood volume was also lower in patients than in controls under baseline conditions, and a further reduction was found after acetazolamide, despite the significant decrease of intraocular pressure. A different reaction was observed in eyes with chronic ocular ischaemia.