Abstract
Abstract: :
Purpose:The objective of this study is to determine the effect of topical dorzolamide 2% and brimonidine 0.2% on capillary blood flow in patients with primary open angle glaucoma (POAG) Methods:Twelve previously untreated patients with primary open angle glaucoma (POAG) were included in this prospective randomized crossover study. Baseline Heidelberg Retinal Flowmeter (HRF) studies were taken at the neuroretinal rim and at the superotemporal (ST), inferotemporal (IT) and nasal juxtapapillary regions to measure the capillary flow in these areas. Patients were randomly assigned to topical dorzolamide 2% tid or brimonidine 0.2% tid and HRF studies taken at 2 and 4 weeks. After a 4 week washout period, repeat baseline, 2 and 4 week HRF studies were taken on the other drug. Images were processed using the SLDF-AFFPIA software. The mean, 5th, 10th, 25th and 50th percentiles of flow were analysed and changes within and between study groups compared using a two-sided t-test. Results:Twenty four treatment periods were analyzed. Baseline intraocular pressures were similiar(p≷0.5) and decreased significantly for both medications by a mean of 3 mmHg (p<0.05). Dorzolamide resulted in increased mean blood flow in the ST and IT views becoming statistically significant in the ST region (+18% p=0.06) at 4 weeks. Analysis at the 5th, 10th, 25th, and 50th percentiles showed similiar results with statistically significant increase in the ST region of the dorzolomide arm at 4 weeks (25th percentile, +30% p=0.05 ; 50th percentile, +21% p=0.05). No statistically significant changes were noted in the rim or nasal regions. Brimonidine showed no significant change flow in any of the analyzed regions at any time point. Conclusion: In POAG, topical dorzolamide significantly increases capillary blood flow in the ST region, independent of its hypotensive effect, while brimonidine has no significant effect on capillary blood flow as measured by the Heidelberg Retinal Flowmeter.
Keywords: 331 blood supply • 390 drug toxicity/drug effects • 489 neuroprotection