Color Doppler flow imaging was performed in 10 healthy controls and in 32 patients with orbital and retinal vascular diseases in order to investigate ocular arterial supply. Abnormal changes of the orbital blood flow observed in case of dural fistula, orbital varicosis and choroidal melanoma is described. In patients with central retinal vein occlusion, substantial arterial flow disturbances were found, such as the reduction of the retinal artery systolic peak flow (p < 0.55) and absence of diastolic flow (p < 0.001). Abnormal changes of the retinal arterial blood flow (reduction of the systolic peak flow or even extinction of the Doppler signal) were also detected in patients with occlusion of the central retinal artery and in some cases of severe stenosis or occlusion of the internal carotid artery. The color Doppler flow imaging appears as a promising technique for the investigation of the vascular diseases of the eye. It may provide useful clues for the differential diagnosis of optic neuropathies and allows haemodynamic characterization of different vascular diseases of the eye such as diabetic retinopathy and glaucoma.