Acute application of dorzolamide increases retinal and epipapillary optic nervehead circulation in healthy subjects

Purpose. Dorzolamide is the first carbonic anhydrase inhibitor (CAI) for the treatment of glaucoma. In addition to the established hypotensive effects, CAI agents have also been reported to have some vasuactive effects. The ocular hemodynamic effects of Dorzolamide had yet to be investigated. This study investigated the effects on retinal and epipapillary circulation following acute application. Methods. In a double-masked placebo-controlled cross-over design, intraocular pressure (IOP) and scanning laser video fluorescein angiography were evaluated in 13 normal subjects at baseline and 2 hours following application. Results. The drug hastened arteriovenous passage time (p<0.05; 18%) and accelerated capillary blood velocities in the macula (p<0.05; 16%) and the superficial optic nervehead (p<0.05; 15%) while remaining arterial and venous diameters unaffected. The placebo failed to alter these measures. IOP also decreased significantly from 15.7 ±0.7 to 13.7 ±0.7 mmHg (p<0.01; 22%) after the acute application. Conclusion. Dorzolamide caused an acute significant increase in retinal and superficial optic nervehead circulation. These results suggests that Dorzolamide could benefit patients with ocular vascular illness characterized by vascular insufficiency.