Related Experiment Video
Updated: Aug 17, 2026

Full-Circle Cauterization of Limbal Vascular Plexus for Surgically Induced Glaucoma in Rodents
Published on: February 15, 2022
The effects of sildenafil on ocular blood flow
Murat Koksal1, Huseyin Ozdemir, Sebnem Kargi
1Ophthalmology Department, Faculty of Medicine, Zonguldak Karaelmas University, Zonguldak, Turkey. mrtkksl@hotmail.com
Purpose:
To investigate the effects of sildenafil, a popular new drug in the treatment of erectile dysfunction, on ocular blood flow.
Methods:
This study was designed as a prospective, double-blind, placebo-controlled study. Twenty participants with erectile dysfunction were given a single oral dose of 100 mg sildenafil, while 10 participants with erectile dysfunction were given placebo. All the participants underwent routine systemic and ophthalmological examinations. Intraocular pressure, systolic and diastolic blood pressure and ocular blood flow (ophthalmic, central retinal, short posterior ciliary arteries) were measured in both eyes before and 1 hour after the dose of sildenafil or placebo. Ocular blood flow measurements were performed using colour Doppler ultrasonography.
Results:
None of the parameters were significantly different between the groups before study drug intake. Although central retinal artery velocities were not changed, ophthalmic artery and short posterior ciliary artery peak systolic velocity, end-diastolic velocity, and mean velocity values were significantly increased 1 hour after drug intake in the sildenafil group compared to the placebo group (p < 0.05).
Conclusion:
Sildenafil causes a significant increase in blood flow in these arteries. A possible role of inhibition of phosphodiesterase-5 in vascular smooth muscles by sildenafil is implicated. Further studies are needed to investigate the effects of sildenafil on ocular blood flow in patients with senile macular degeneration, diabetic retinopathy and glaucoma.
Related Concept Videos
Treatment for Pulmonary Arterial Hypertension: Phosphodiesterase Inhibitors
Among the PDE5 inhibitors, sildenafil (Revatio) stands out as a competitive and selective inhibitor. It operates by elevating cellular levels of cGMP and augmenting signaling through the cGMP-PKG pathway, promoting vasodilation. Upon oral...
Open Angle Glaucoma: Treatment
Drugs such as carbonic anhydrase inhibitors, α2- and...
Ophthalmic Drug Delivery Systems
Nitric Oxide Signaling Pathway
Glaucoma: Overview
Angle Closure Glaucoma: Treatment