The effects of sildenafil on retrobulbar and retinal circulation were studied in 18 adult male, albino, homozygous rabbits, of the New Zealand White breed, randomly divided into 3 groups of 6 animals, for drug treatment at a dose of 3.5mg kg-1 every 24 hours, for 7, 15 and 30 days. Nine animals used for control were treated with saline solution at 0.9%. It was evaluated intraocular pressure (IOP), mean arterial pressure (MAP), ocular perfusion pressure (PPO), B-mode ultrasonography and fluorescein angiography before and at the end of treatments. A slight decrease in results of IOP, MAP and PPO after treatment with sildenafil was evident, however, there was no statistical significance. It was observed significant increased diameter of the ophthalmic artery after 7 and 30 days of treatment and decreased mean arterial pressure after 7, 15 and 30 days of treatment, with no statistical difference. On fluorescein angiography, it was observed that the arterial, arteriovenous and venous stages initiated more rapidly in animals after treatment, with significant difference on the arteriovenous stage at the 7th and 15th days. It was possible to admit that the sildenafil citrate improves blood circulation in the retina of rabbits, by increasing the speed of blood flow and decreasing the perfusion pressure.
rabbits; sildenafil citrate; retrobulbar circulation; retinal circulation; ultrasonography; fluorescein angiography
