A Double-masked Randomized Cross-over Study Comparing Of The Effect Of Latanoprost/timolol And Brimonidine/timolol Fixed Combination On Intraocular Pressure And Ocular Blood Flow

Abstract

Purpose: : : Ocular blood flow dysregulation has been implicated in the pathogenesis of glaucoma. In vitro and in vivo experiments indicate that brimonidine may be a potent vasoconstrictor in ocular vessels. In the present study we therefore compared the effects of latanoprost/timolol (L/T) and brimonidine/timolol (B/T) fixed combination on intraocular pressure (IOP) and ocular blood flow.

Methods: : In the present study, which followed a randomized, double-masked two-way cross-over design, 16 patients with primary open angle glaucoma and 2 patients with ocular hypertension were included. The patients underwent a 6 weeks treatment with Xalacom® (L/T) and a 6 week treatment with Combigan® (B/T). The washout period for previous study medication was 4 weeks. All measurements were scheduled at 8:00 am. Optic nerve head blood flow (ONHBF) was measured using laser Doppler flowmetry, retrobulbar flow velocities were measured using color Doppler imaging.

Results: : The mean baseline IOP was 22.3±5.4 mmHg. Both drugs were equally effective in reducing intraocular pressure (L/T: 32.3±11.3%; B/T: -27.6±10.5%; p = 0.35). Neither L/T nor B/T altered ONHBF (L/T: -2.6±13.1%; B/T: -4.4±12.4%; p = 0.58) and no effect on mean flow velocities in the retrobulbar vessels was seen with either of the two treatments (CRA: p = 0.26, PCAs: p = 0.14, OA: p = 0.81).

Conclusions: : In the present study a 6 weeks treatment with L/T or B/T was equally effective in reducing IOP. In addition, none of the administered drugs induced any significant effect on ocular blood flow parameters.

Clinical Trial: : http://www.clinicaltrials.gov NCT00706927

Keywords: blood supply • optic nerve