The extracranial carotid arteries of 165 patients with retinal ischaemic symptoms were examined with duplex ultrasound. Both the degree of stenosis and the morphological appearance of the lesions were examined. Ipsilateral carotid artery disease was found in 88% of patients. Degrees of stenosis of between 50-99% were found in 33% of patients, the majority of these lesions being complex heterogeneous in nature. Stenosis of < 50% was found in 40% of arteries. The majority of lesions causing < 20% stenosis were homogeneous in nature. However, in stenosis of 20-49%, 63% of lesions were found to be complex heterogeneous. A similar distribution of lesions was found in the contralateral carotid arteries. It is important to examine both ipsilateral and contralateral arteries, and to evaluate the morphological characteristics of all lesions causing > 20% stenosis.