Orbital ultrasound in the ocular ischaemic syndrome.

The ocular ischaemic syndrome illustrates well the effects of hypoperfusion of the globe and is a useful model for studying disorders of the orbital circulation. Recent advances in orbital ultrasound techniques have provided a non-invasive method of examining flow velocities in the orbital vessels, particularly the ophthalmic artery. Orbital ultrasound studies were performed on 3 cases of the ocular ischaemic syndrome. Continuous or intermittent reversal of blood flow in the ophthalmic artery was seen in all cases. How this phenomenon relates to the symptoms and signs in affected patients, and the role of orbital ultrasound in the investigation of the ocular ischaemic syndrome, are discussed.