Figure 1

PSV and EDV values in ophthalmic artery after sildenafil (100 mg), tadalafil (20 mg) and placebo uptake. After sildenafil uptake, a significant increase (P<0.01) in OA PSV and EDV was observed only at 60 min after drug uptake. After tadalafil uptake a significant increase in OA PSV was observed at 1, 4, 8, 12, 24 (P<0.001), and 36 h (P<0.01). A significant increase in OA EDV values was observed at 1, 4, 8 (P<0.001), and 12 h, 24 h (P<0.01) after drug uptake. EDV, end-diastolic velocity; OA, PSV; peak systolic velocity.