To assess the diagnostic value of an extensive cardiac screening and of carotid artery duplex scanning in patients suspected of suffering from retinal embolism, we examined 41 consecutive patients (mean age 59.6 years, range 36-74) who presented either with amaurosis fugax or with a retinal artery occlusion. In spite of extensive investigations, we found no cause in 27 patients (66%). In 11 patients (27%), symptoms were likely to be due to a stenosis or an occlusion of the ipsilateral carotid artery. In only 1 patient (2%), the heart was likely to be a source of embolism. We conclude that in patients in this age group suffering from either amaurosis fugax or a retinal artery occlusion, a carotid artery duplex scanning should be performed first as this investigation is more likely to provide useful information than an extensive cardiac screening (ECG, Holter 24-hour monitoring and precordial echocardiography).