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

Aim: To examine the relation between stenosis of the internal carotid artery (ICA) and pulsatile ocular blood flow (POBF). Methods: 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. Results: There was a significant negative correlation between POBF and ipsilateral ICA stenosis (Pearson correlation coefficient, r = -0.516, p <0.0001). 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 μl/min with a mean of 970.72 μl/min. Conclusion: Low or unrecordable POBF may signify severe stenosis of the internal carotid artery. POBF is not a direct reflection of ipsilateral ICA blood flow.