Retinal artery occlusions are acute vascular diseases. Very often they are caused by an embolisation. Rarely a thrombosis is caused by an arteriitis. In the acute phase diagnosis in most of the cases can be made by ophthalmoscopy due to the whitish retinal edema and in central retinal artery occlusion the cherry red spot. Difficulties in making the diagnosis can occur in the chronic stage, especially after reperfusion of the retinal vessels, when the fundus colour returned to normal again. Several diagnostic procedures help to make the diagnosis. Unfortunately there is no generally accepted therapeutic approach for retinal artery occlusions. The visual prognosis often is poor. It is very important to rule out underlying diseases because the patients have an increased risk for stroke or cardiovascular events.