Effects of brinzolamide on ocular haemodynamics in healthy volunteers

Abstract

Aim: A prospective, randomised study to evaluate effects of brinzolamide on ocular haemodynamics in healthy volunteers. Methods: 30 volunteers (12 men, 18 women; 28.3 (SD 7.8) years) were prospectively randomised to either brinzolamide or placebo during a 2 week double masked treatment trial. Examinations were performed at baseline and after 2 weeks of treatment. Intraocular pressure was measured and automatic static perimetry (Humphrey field analyser, 24-2) and contrast sensitivity (CSV 1000, Vector Vision) were performed. Retrobulbar blood flow velocities (peak systolic and end diastolic velocity) and resistive indices (RI) of ophthalmic artery, central retinal artery and of temporal and nasal short posterior ciliary arteries were measured by colour Doppler imaging (Sonoline Sienna Siemens). In video fluorescein angiograms (scanning laser ophthalmoscope, Rodenstock) arteriovenous passage time (AVP, dilution curves) and peripapillary diameters of retinal arterioles and venules were measured by means of digital image analysis. Results: Intraocular pressure was significantly decreased by brinzolamide (p,0.0001). Neither brinzolamide nor placebo changed visual field global indices after treatment. Contrast sensitivity at 3 cycles per degree was significantly higher in the placebo group (p,0.05). Apart from an increase of RI in ophthalmic artery under placebo treatment (p,0.05) there was no effect in retrobulbar haemodynamics in both groups. Brinzolamide therapy alone resulted in a significant reduction of AVP compared to baseline (p,0.05), while peripapillary retinal vessels diameters remained unaffected. Conclusions: Apart from the expected decrease of intraocular pressure brinzolamide showed no significant change in retrobulbar haemodynamics, but a significant shortening of AVP. Since in glaucoma AVP is prolonged indicating vascular dysfunction this effect might be beneficial in glaucoma therapy.

A Comparison of the Long-Term Effects of Dorzolamide 2% and Brinzolamide 1%, Each Added to Timolol 0.5%, on Retrobulbar Hemodynamics and Intraocular Pressure in Open-Angle Glaucoma Patients

“…Our fi ndings partially disagree with those published by Kaup and colleagues 25 who reported that retrobulbar hemodynamics remained unaltered in healthy subjects treated with brinzolamide 1% BID.…”

“…It is very diffi cult to compare our results with those published by Kaup and colleagues 25 because the subjects included in our study were patients with glaucoma. We found that brinzolamide signifi cantly increased EDV in the CRA and SPCA.…”

“…Kaup and colleagues 25 reported that topical brinzolamide accelerated the retinal arteriovenous passage time, while the retinal vessel diameters and retrobulbar hemodynamic parameters remain unaltered.…”

Ocular Pharmacokinetics of Dorzolamide and Brinzolamide After Single and Multiple Topical Dosing: Implications for Effects on Ocular Blood Flow

“…Topical application of dorzolamide results in significant improvement in blood flow to the retina and optic nerve head (Harris et al, 1996;Martinez and Sanchez, 2007). However, very few studies have reported the effect of brinzolamide on OBF (Barnes et al, 2000;Kaup et al, 2004;Siesky et al, 2008). Furthermore, the reports from these studies are not conclusive.…”

“…Furthermore, the reports from these studies are not conclusive. Barnes et al (2000) showed significant improvement in optic nerve head blood flow after topical application of brinzolamide in Dutch Belted rabbits, whereas Kaup et al (2004) showed no effect of brinzolamide on OBF. A recent clinical comparison of the effects of dorzolamide and brinzolamide on OBF in a POAG patient showed an increase in retrobulbar blood flow with dorzolamide but not with brinzolamide (Martinez and Sánchez-Salorio, 2009).…”