Orbital ultrasonography.

Ultrasonography is a harmless, painless procedure that can qualitatively and quantitatively evaluate various orbital abnormalities. The characteristic acoustic changes that typify orbital lesions and the techniques used to best display them are described. The internal reflectivity of an orbital lesion can be correlated with its histologic features. The demonstration of subtle enlargements of the ocular muscles and optic nerve by ultrasound techniques is emphasized.