Orbital colour Doppler imaging.

Colour Doppler imaging (CDI) is an ultrasonic method for qualitatively and quantitatively assessing blood flow. Recently this technique has been adapted for investigation of the orbital, optic nerve and ocular vasculature. We discuss the history, principles and methodology of this examination technique for ophthalmology. Also described are normal haemodynamic characteristics as well as the findings in common pathological states involving derangements of orbital blood flow. Although CDI is relatively new to ophthalmology it has already proved to be of benefit in conditions with altered orbital, ocular and optic nerve blood flow. In the future it is expected that the indications for the applications of CDI will become more clearly defined and that orbital CDI will be more widely available and utilised, especially in the investigation of vascular diseases of the orbit, optic nerve and retina.