The response of blood flow velocity in the ophthalmic artery and blood flow of the finger to warm and cold stimuli in glaucomatous patients.

Vasospasm appears to be a probable risk factor in the development of glaucoma. Transcranial Doppler (TCD) can detect vasospasm in cerebral vessels. It gives reproducible readings for ophthalmic artery blood velocity measurements. We used the TCD to measure peak flow velocity, mean flow velocity, and end-diastolic flow velocity in the ophthalmic artery and a laser Doppler flow meter to measure blood flow in the fingers of 17 patients with chronic open-angle glaucoma (COAG), 13 patients with normal tension glaucoma (NTG), and 8 nonglaucomatous subjects with normal eyes (normals). The opposite hand to that in which the measurements were made was challenged with warm (40 degrees) and cold (4 degrees) water. Five measurements of the ophthalmic artery velocity and finger flow were recorded: the first at baseline, the second during warming of the hand, the third after warming of the hand, the fourth when the hand was immersed in iced water, and the fifth after the hand was removed from the cold water. There was no detectable change in the ophthalmic artery blood velocities but significant decreases in the finger flow measurements when the opposite hand was immersed in cold water. These changes were present in all three diagnostic groups (P < 0.001 for COAG; P < 0.005 for NTG; P < 0.05 for normals). The findings suggest a reflex vasospasm to cold in the finger circulation of most persons but no measurable changes in the ophthalmic artery.