The aim of this study was to evaluate the effect of sildenafil on ocular hemodynamics in a group of men with erectile dysfunction in 3 months regular use. A total of 15 patients with erectile dysfunction were included in this prospective study. All patients received 50 mg doses of sildenafil (Viagra, Pfizer) two times per week regularly for 3 months. The following examinations were performed on both eyes before and after sildenafil treatment: best-corrected visual acuity (BCVA), intraocular pressure (IOP), color vision, anterior segment, and fundus examination. Using color Doppler imaging, we measured hemodynamic variables in the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary artery (SPCA). No significant changes in BCVA, color vision and IOP were found after sildenafil treatment. The anterior segment and fundus examinations showed no abnormalities. All Doppler parameters of OA, CRA, and SPCA remained nonsignificant for both eyes after sildenafil treatment. Oral sildenafil in 3 months regular use seems to have no effect on ocular hemodynamics.