A 62-year-old man with diabetes of 24 years' duration was referred by his physician to an ophthalmologist. The man presented with temporal headache and reduced vision in the right eye of 2 weeks' duration. His most recent HbA was 86 mmol/l (10%). The best corrected vision in the right eye was 1/60. The right eye showed episcleral congestion with mid-dilated pupil and neovascularization of the iris with nuclear sclerosis of the lens (Fig. 1a). Intraocular pressure was 34 mmHg and the fundus showed few mid-peripheral blot haemorrhages (Fig. 1b). Left eye vision was 6/9 with few blot haemorrhages in the posterior segment. Carotid Doppler revealed complete occlusion of the right internal carotid artery.