Effects of dorzolamide/timolol fixed combination on retrobulbar hemodynamics in pseudoexfoliative glaucoma

In our study we aimed to evaluate the short-term effects of dorzolamide/timolol on ocular perfusion pressure and retrobulbar blood flow in patients with pseudoexfoliative glaucoma (PXG). This prospective observational cross-sectional study enrolled 22 eyes of 22 newly-diagnosed patients with PXG in a single center. All of the patients received a fixed combination of dorzolamide/timolol. Besides routine ophthalmologic examination, the retrobulbar hemodynamic parameters in the ophthalmic artery, central retinal artery, and short posterior ciliary arteries were measured in all participants at baseline and the 3rd month using color Doppler imaging. The mean intraocular pressure (IOP) was 22.3 +/- 2.1 mmHg at baseline and reduced to 17.4 +/- 2.3 mmHg at the 3rd month (p < 0.05). None of the retrobulbar parameters, except peak systolic velocity and resistive index in temporal short posterior ciliary arteries, changed significantly on therapy with dorzolamide/timolol fixed combination when the results were analyzed at Month 3. The drug significantly decreased the peak systolic velocity (p = 0.044) and reduced the resistive index in 0.04 units, 95% confidence interval 0.03-0.05, (p < 0.001) in the temporal short posterior ciliary arteries. This study reports that the retrobulbar hemodynamics might be affected less than expected by dorzolamide/timolol fixed combination in patients with PXG although the reduction of IOP was statistically significant.