The role of colour flow Doppler ultrasonography in the investigation of disease in the eye and orbit.

Colour flow Doppler ultrasonography is a relatively new technique in which colour-encoded representations of flowing blood are imposed over a conventional grey-scale ultrasound image. This allows interrogation of a relatively large volume of tissue to determine the presence and direction of blood flow. The waveform tracings are then evaluated by means of conventional Doppler imaging. We demonstrate examples of normal vascular structures in the orbit and describe the application of this technique in the investigation of vascular disease, such as carotid-cavernous fistula and ischemic disease. The technique can also be used to evaluate ocular membranes and masses. Colour flow Doppler imaging promises to be an important advance in ophthalmic ultrasonography.