Short-term effect of dipyridamole on blood flow velocities in the extraocular vessels.

Dipyridamole is known to inhibit platelet aggregation and to induce vasodilatation. It has been shown that dipyridamole increases blood flow in various tissues in humans as well as in the eyes of animals. We studied the influence of dipyridamole in a prospective open trial in 23 patients with impaired ocular circulation due to different causes, based on experienced clinical judgement, such as anterior ischemic optic neuropathy, vasospastic syndrome, glaucoma, or central retinal vein occlusion. Blood flow velocities in the ophthalmic artery, central retinal artery and vein, one lateral and one medical posterior ciliary artery were measured using a Siemens Quantum 2000 color Doppler device. Blood flow velocities were measured before and under treatment. Dipyridamole increased blood flow velocities significantly in all vessels measured. Therefore, it seems promising to evaluate the effect of dipyridamole over a longer period in patients with impaired ocular blood flow.