Ophthalmic artery flow direction on color flow duplex imaging is highly specific for severe carotid stenosis.
Reynolds PS, Greenberg JP, Lien LM, Meads DC, Myers LG, Tegeler CH. Ophthalmic artery flow direction on color flow duplex imaging is highly specific for severe carotid stenosis. J Neuroimaging. 2002 Jan; 12(1):5-8.