The effect of sildenafil on retinal blood velocity in healthy subjects

Purpose: It has been suggested that Sildenafil may have beneficial therapeutic effects in the treatment of neurodegenerative disorders. The retinal circulation is of significant interest as a marker of cerebral vascular disease since the retinal and cerebral vasculatures share many morphological and physiological properties, yet only the retinal circulation can be directly visualized. Therefore, our aim was to assess the change induced by Sildenafil on retinal blood velocity. Methods: Retinal flow velocity was measured 0.5, 3 and 6 h following administration of 100 mg of Sildenafil using the Retinal Function Imager. Results: No clinical change in either systemic blood pressure or retinal flow velocities were observed. However, when controlling for heart rate and blood pressure, a significant drop in venous flow velocity 6 h following treatment (mean drop 0.3 +/- 0.07; 95% CI: 0.44-0.56, P= 0.023) was revealed. Conclusions: In healthy volunteers, retinal venous flow velocity was significantly reduced at the 6-h time point following Sildenafil treatment. No effect was observed on arterial retinal flow velocity.