Comparative analysis of the effects of brimonidine and dorzolamide on ocular blood flow velocity in patients with newly diagnosed primary open-angle glaucoma.

The aim of this study was to evaluate the effects of brimonidine 0.2% and dorzolamide 2% on the ocular blood flow velocity in patients with newly diagnosed primary open-angle glaucoma (POAG). Forty-four (44) patients with newly diagnosed POAG were included in a prospective, comparative, randomized clinical study. Twenty-six (26) healthy volunteers, whose age and gender matched, were recruited to compare the baseline hemodynamic characteristics of the patients. After a complete eye examination, baseline blood flow velocity measurements of the retrobulbar vessels were made with color Doppler ultrasonography. Patients were randomly assigned to receive either brimonidine 0.2% or dorzolamide 2% for a 3-month period. Blood flow velocity measurements were repeated after 3 months. Both brimonidine and dorzolamide significantly reduced the intraocular pressure. The baseline ophthalmic artery pulsatility index was higher in patients with POAG than control subjects. Whereas there was a significant increase in peak systolic velocity of the central retinal artery, no significant change was observed in the other vessels with brimonidine and dorzolamide treatment. There was little difference, in terms of ocular blood flow velocity, between newly diagnosed glaucoma patients and control subjects. Both topical brimonidine and dorzolamide significantly reduced the intraocular pressure without altering ocular blood flow velocity in patients with newly diagnosed POAG.