This study evaluates ocular blood flow changes in both ocular Behcets disease (BD) and non-ocular BD (with or without thrombotic disease) and compares these findings with a healthy control group. A total of 90 eyes with BD were evaluated with a range of ocular involvement from no involvement to active uveitis. These affected eyes were compared with 120 matched control eyes. All eyes were measured using colour Doppler ultrasonography (CDU) assessing ophthalmic, central retinal and ciliary artery flow parameters. Results from this significant sample size showed major haemodynamic changes in the ophthalmic vessels of ocular Behcet patients. In addition, in non-ocular BD patients with thrombolysis, blood flow parameters were affected more than those without thrombolysis and healthy controls. This suggests that CDU may detect ocular blood flow alterations before ocular clinical manifestations appear in BD patients, creating opportunity for earlier interventions.