Clinical features of transient monocular blindness and the likelihood of atherosclerotic lesions of the internal carotid artery.

To assess which features of transient monocular blindness (TMB) are associated with atherosclerotic changes in the ipsilateral internal carotid artery (ICA), 337 patients with sudden, transient monocular loss of vision were prospectively studied. History characteristics of the attack were compared with the presence of atherosclerotic lesions of the ipsilateral ICA. All patients were directly interviewed by a single investigator. Of all patients, 159 had a normal ICA on the relevant side, 33 had a stenosis between 0%-69%, 100 had a stenosis of 70%-99%, and 45 had an ICA occlusion. An altitudinal onset or disappearance of symptoms was associated with atherosclerotic lesions of the ipsilateral ICA. A severe (70%-99%) stenosis was also associated with a duration between 1 and 10 minutes, and with a speed of onset in seconds. An ICA occlusion was associated with attacks being provoked by bright light, an altitudinal onset, and the occurrence of more than 10 attacks. Patients who could not remember details about the mode of onset, disappearance, or duration of the attack were likely to have a normal ICA. Our findings may facilitate the clinical decision whether or not to perform ancillary investigations in these patients.