Doppler ultrasound velocity mapping of extra-ocular muscles: a preliminary report.

Colour doppler imaging and conventional spectral doppler/B-mode techniques were used to detect and quantify rectus muscle movement during voluntary saccades. A velocity gradient was evident in all muscles studies-low velocities near the muscle origin at the back of the orbit increasing linearly to a maximum near the muscle insertion on the globe. A consistent reduction in velocity occurred along muscles injected with botulinum toxin