Depending on the direction of flow with respect to the transducer, the flow is displayed in either red or blue. The colours can be arbitrarily assigned, but by convention, and in this study, flow towards the transducer is depicted as red and away from the transducer as blue. When the eye and orbit are examined through the eyelids, the ultrasound beam is almost parallel to the orbital and ocular vessels; thus most arterial flow is depicted in red. Arteries can usually be distinguished from veins by noting the pulsatility of the former. Pulsed Doppler spectral analysis also helps to distinguish between pulsatile arterial and non-pulsatile venous flow and allows quantification of data. When the ultrasound beam is at an angle of 90°t o a vascular structure, or ifa vessel contains only stagnant blood, no Doppler flow information is obtained and the structure is shown in grey scale display only.Our patient was a 38-year-old woman who had positional proptosis of the left eye and classic findings of an orbital varix on computed tomography.5 26 A contact gel (Aquasonics) was