Although some patients may be asymptomatic, a branch retinal vein occlusion (BRVO) usually presents with central or paracentral impaired vision (+/- distortion). The main risk factors, other than age (arterosclerosis), are hypertension and diabetes. Less common aetiologies include hyerviscosity conditions which interfere with retinal blood flow eg polycythaemia, chronic leukaemia, sickle cell disease, or diseases which result in inflammation of the retinal veins (periphlebitis) such as sarcoidosis.
