Unrecordable pulsatile ocular blood flow may signify severe stenosis of the ipsilateral internal carotid artery

To examine the relation between stenosis of the internal carotid artery (ICA) and pulsatile ocular blood flow (POBF).In 57 eyes of 30 patients who were referred for Doppler ultrasound examination of the ICA we measured POBF and analysed the correlation with degree of ipsilateral ICA stenosis.There was a significant negative correlation between POBF and ipsilateral ICA stenosis (Pearson correlation coefficient, r=-0.516, p0.0001). In 14 eyes POBF could not be measured by the OBF tonometer, and in 11 of these cases (79%) severe stenosis (75%) of the ipsilateral ICA was present. When these eyes were excluded from analysis, there was no correlation between POBF and ICA stenosis (r=-0.02, p=0.91). Among these 43 eyes in which POBF could be measured it ranged 667-2095 microl/min with a mean of 970.72 microl/min.Low or unrecordable POBF may signify severe stenosis of the internal carotid artery. POBF is not a direct reflection of ipsilateral ICA blood flow.