BACKGROUND Several general diseases cause blindness in patients with simultaneous combined retinal artery and vein occlusion. METHODS We examined 14 patients with acute unilateral visual loss due to combined retinal artery and venous occlusions. All 14 patients presented at the Polyclinic over a period of about 3 years. Fluorescein angiography was carried out in 12 patients to confirm the diagnosis. Ten patients underwent Doppler sonography and 11 echocardiography. RESULTS Concerning systemic diseases, 11 of our 14 patients presented several cardiovascular risk factors, i.e., immunocytoma and arterial hypertension and hypercholesterolemia in one patient; another patient had chronic bronchitis, tachycardia and hypercholesterolemia. Six patients presented coagulation anomalies, and eight patients had arterial hypertension.Doppler sonography revealed normal carotid arteries in nine of ten patients. In 8 of 11 patients, echocardiography displayed no cardiac abnormalities.Ophthalmoscopy revealed no emboli in any of these patients. CONCLUSIONS Unilateral simultaneous combined incomplete retinal artery and venous occlusions should be considered as one entity. Eleven of our patients presented comorbidities reflecting several cardiovascular risk factors. Immunological diseases, malignancies and coagulopathies can cause this ocular disorder, resulting in blindness. No emboli were found in any of these patients. Patients suffering from acute visual loss must be examined for the presence of systemic diseases to enable therapy at an early stage.