The purpose of this study was to evaluate the hemodynamic changes occurring in the ophthalmic vasculature of eyes with Behçet's disease in a controlled clinical trial. Both eyes of patients with retinal involvement due to Behçet's disease were consecutively evaluated and were established as having mild or severe retinal vasculitis according to the ophthalmoscopic and fundus fluorescein angiographic findings. One eye from each patient was randomly selected and 25 eyes with mild to moderate and 25 eyes with severe vasculitis were identified. Color Doppler imaging (CDI) was used to quantitate blood flow velocities and vascular resistance in the ophthalmic artery (OA), central retinal artery (CRA) and central retinal vein (CRV) of these patients and those of 25 healthy volunteers. All three groups were age- and sex-matched. In the OA, peak systolic, end diastolic and average flow velocities were significantly higher in patients with Behçet's disease than in the control group (p < 0.05). CRA blood flow velocities of patients with severe retinal involvement were significantly lower than those with mild to moderate vasculitis and control groups and the average vascular resistance was significantly higher than in the control group (p < 0.05). Additionally, the average blood flow velocities in the CRV of patients with severe vasculitis were significantly lower than in mild to moderate vasculitis and control patients. Marked circulatory changes were seen in the ophthalmic vasculature of eyes with Behçet's disease. Although larger studies are required to define the true sensitivity and specificity of this technique, these initial results suggest that CDI could play a major part in the assessment of patients with ocular Behçet's disease.