[Vascular diseases of the retina].

Retinal venous occlusion are usually associated with hypertension and arteriosclerosis; visual loss can be mild or severe. Two complications are related with a poor visual outcome: macular oedema and severe retinal ischaemia. Retinal artery occlusion is responsible for a sudden visual loss, usually caused by embolism. In cases without early reperfusion, visual loss is irretrievable. Retinal vasculitides, characterized by inflammation of blood vessels, are isolated or associated with systemic diseases. Visual prognosis is usually poor, particularly in cases of vascular occlusions or retinal necrosis.