We have treated 23 patients with central retinal artery occlusion by intra-arterial fibrinolysis, a method already in use for treatment of thromboembolic occlusion of the cerebral arteries. Fibrinolysis was carried out through a microcatheter placed in the origin of the ophthalmic artery. When ophthalmic artery cannot be catheterised, treatment can be carried out indirectly via the maxillary-ophthalmic anastomoses. In 18 cases urokinase was used in doses of 200,000-1,200,000 units; in 5 patients recombinant tissue plasminogen activator was used. Six patients showed marked improvement or total recovery, and six partial recovery, with improvement of visual acuity or a field defect. The worst results were obtained in six patients where the mean delay between the appearance of symptoms and initiation of treatment was more than 20 h. Intra-arterial thrombolysis led to a better outcome in acute occlusion of the central retinal artery than might have been expected with conservative treatment. A good prognosis is to be expected when treatment starts within the first 6-8 h, when some vision remains and when there is less retinal oedema.