Abstract
Abstract: :
Purpose: Previous studies have suggested a decreased choroidal circulation in AMD. The purpose of this study was to investigate the effects of sildenafil citrate (Viagra) on the foveolar choroidal circulation in patients with age related macular degeneration (AMD). Methods: This investigation was a double–blinded, randomized, placebo–controlled, crossover study. Fifteen male AMD patients received a dose of 100 mg of sildenafil or matching placebo on two separate days. Laser Doppler flowmetry (Oculix instrument) was used to assess relative choroidal blood velocity (ChBVel), volume (ChBVol) and flow (ChBFlow) in the study eye at baseline, prior to administration of the drug, and then at 30, 90, 180, 300 min after dosing. Best corrected visual acuity (BCVA), contrast sensitivity (CS), mean arterial blood pressure (BPm), heart rate (HR), intraocular pressure (IOP) and ocular perfusion pressure (PP) were determined. Analysis of variance (ANOVA) for repeated measures was used in the analysis of the data. Results: In comparison to placebo, sildenafil did not cause any statistically significant change in mean ChBVel (P = 0.12), ChBVol (P = 0.24) or ChBFlow (P= 0.46). We estimated that we have 95% power to detect a 12% difference in the change ChBFlow between the two groups. There were no statistically significant changes in CS (P = 0.59), BCVA (P = 0.58), IOP (P = 0.81), or HR (P = 0.07) throughout the study. Significant decreases of 15% in BPm (P = 0.006) and of 22% in PP (P = 0.006) were observed 30 min after sildenafil. A significant inverse correlation was detected at 180 and 300 minutes between ChBVel and BPm (R = –0.56, P = 0.03; and R = –0.53, P = 0.04, respectively) and between ChBVel and PP (R = –0.59, P = 0.02; and R= –0.55, P = 0.03, respectively). No similar correlation was found after the administration of placebo. Conclusions: Administration of sildenafil citrate was not associated with any statistically significant change in the foveolar choroidal circulation in AMD patients.
Keywords: age-related macular degeneration • blood supply • drug toxicity/drug effects