In a prospective evaluation of 39 patients who had arteriography for suspected carotid stenosis, suction ophthalmodynamometry correctly identified 86% of the patients who had radiographically demonstrable unilateral or asymmetric obstructions. This compares favorably with carotid compression tonography, oculoplethysmography, and Doppler flow studies. The false-positive rate was 27%, a figure higher than the latter two noninvasive tests.