Effect of Topical Bunazosin Hydrochloride on Optic Nerve Head and Juxtapapillary Retinal Circulation in Normal Subjects

Abstract

Abstract: : Purpose:To evaluate the effect of topical bunazosin hydrochloride, selective alpha-1 antagonist, on the tissue circulation in optic nerve head and juxtapapillary retina in nomal subjects. Methods:Fifteen normal subjects were enrolled in a randomized, double masked, pracebo-controlled crossover study. In each subject either bunazosin hydrochloride (0.01%) or placebo was instilled into right eye. Blood flow measurements were performed before the instillation, one and two hours after the instillation using the Heidelberg Retina Flowmeter (HRF) which is intended to assess ocular blood flow by scanning laser Doppler flowmetry. Values of HRF parameter (flow) at superior neuroretinal rim area of optic nerve head, and supero-nasal and supero-temporal juxtapapillary retinal area were measured. The crossover study was performed after four-weeks interval. Results:After one hour of instillation of bunazosin hydrochloride or placebo, the mean flow of bunazosin hydrochloride treated eyes was 13.0% higher than the baseline(P<0.01,Wilcoxon signed rank test) and significantly higher than placebo treated eyes(P<0.05,Wilcoxon signed rank test) at neuroretinal rim area, whereas the mean flow of placebo treated eyes showed no significant difference under all testing conditions at neuroretinal rim area and juxtapapillary retinal area both. Conclusions:These results suggest that topical bunazosin hydrochloride significantly increases the tissue circulation of neuroretinal rim after one hour of instillation.

Keywords: optic disc • imaging/image analysis: clinical • blood supply