OBJECTIVE The hemodynamics of the retrobulbar arterial circulation of patients with central retinal vein occlusion were evaluated in order to better understand the pathophysiology of this disease. METHODS Color Doppler imaging was used to measure the peak systolic velocity and vascular resistance (pulsatility index) in the retrobulbar arteries of involved eyes and clinically healthy fellow eyes of patients with central retinal vein occlusion and in the control eyes of age- and sex-matched healthy volunteers. RESULTS Average peak systolic velocity was significantly lower and average vascular resistance was significantly higher in the central retinal artery of involved eyes of patients with central retinal vein occlusion compared with clinically healthy fellow eyes and compared with control eyes. There also was a trend toward higher vascular resistance in the central retinal artery of clinically healthy fellow eyes of patients with central retinal vein occlusion compared with control eyes. In the ophthalmic arteries and short posterior ciliary arteries, vascular resistance was significantly higher in both the involved eyes and clinically healthy fellow eyes of patients with central retinal vein occlusion compared with control eyes. CONCLUSIONS Color Doppler imaging parameters of the central retinal artery circulation were abnormal in eyes with central retinal vein occlusion, suggesting impaired arterial blood flow associated with this disease. The high vascular resistance in the central retinal arteries, ophthalmic arteries, and short posterior ciliary arteries of both involved and clinically healthy fellow eyes of patients with central retinal vein occlusion suggests that diffuse small vessel disease may predate and contribute to the development of central retinal vein occlusion.