Dorzolamide and ocular blood flow in previously untreated glaucoma patients: a controlled double-masked study

Purpose: The aim of this study was to investigate the haemodynamic effects of topical dorzolamide treatment in eyes with newly detected and previously untreated glaucoma. Methods: Forty-seven patients with open angle glaucoma were consecutively randomized to dorzolamide versus placebo TID during a 6-week double-masked treatment trial. Ocular blood flow was investigated at baseline and on therapy using colour Doppler imaging of the retrobulbar vessels and scanning laser ophthalmoscope fluorescein angiograms of the retinal circulation. Results: None of the flow parameters, retrobulbar or retinal, changed significantly on therapy when the results were analysed with the Bonferroni method. Analysis with non-simultaneous tests also failed to reveal any significant changes either in retrobulbar flow velocities in the central retinal artery, ophthalmic artery or in the short posterior ciliary arteries, or in the retinal parameters (arm-retina time, arteriovenous passage time, mean dye velocity or macular capillary velocity), while capillary velocities at the optic disc decreased significantly in the dorzolamide group (P = 0.03). Intraocular pressure reduction was significantly more pronounced in the dorzolamide group (P = 0.002), with -4.8 +/- 2.9 mmHg (P < 0.0001) versus -1.8 +/- 3.0 mmHg in the placebo group (P = 0.006). Conclusions: The present study indicated no measurable vascular effects from topical dorzolamide treatment in previously untreated glaucoma eyes.