A total of 263 patients underwent either periorbital ophthalmosonometry (Doppler ultrasound) or a combination of ophthalmosonometry and supraorbital photoplethysmography (SOPPG) to determine the presence or absence of a hemodynamically significant lesion (occlusion or greater than 50% reduction in lumen diameter), There were 522 vessels studied with Doppler ultrasound and 272 vessels with a combination of the two modalities. The tests were correlated with carotid arteriography to determine their accuracy. Overall accuracy of the Doppler ultrasound examination was 95%. A normal Doppler ultrasound examination was obtained in 367 vessels and arteriography confirmed the absence of a hemodynamically significant lesion in 93%. Of 155 vessels with an abnormal Doppler examination, 149 (96%) were proven on arteriography to have hemodynamically significant lesions. The Doppler ultrasound examination had a high incidence of falsenegative examinations (26%) in those vessels that were between 50% and 99% stenotic, however. The SOPPG alone had a high incidence of false-positive examinations (19%); however, in 155 vessels with a normal SOPPG, 98% were proved to have no hemodynamically significant lesion. The combination of Doppler ultrasound and SOPPG was highly accurate in identifying patients with hemodynamically significant lesions. Of 97 vessels with such lesions, 96 (99%) had either an abnormal Doppler ultrasound examination or an abnormal SOPPG. In 240 vessels with concordant results of the Doppler ultrasound and SOPPG, the presence or absence of a hemodynamically significant lesion was accurately predicted in 235 (98%).