Ophthalmic ultrasound imaging is based on the emission of an acoustic pulse and reception of the pulse after it has been reflected off ocular tissues. It has been used in the form of A and B-scans for many decades. Ultrasound biomicroscopy is a new imaging technique that uses high frequency ultrasound to produce images of the eye at near microscopic resolution. The use of a higher frequency transducer allows for a more detailed assessment of the anterior ocular structures than was available using traditional B-scan ultrasound. It also decreases penetration, but increases the resolution of the imaged structures. Lateral and axial resolutions are estimated to be 40 and 20 microns, respectively. High-frequency ultrasound biomicroscopy provides high-resolution in vivo imaging of the anterior segment in a noninvasive fashion and can scan through opaque media. In addition to the tissues easily seen using conventional methods, such as the cornea, iris, and sclera, structures including the ciliary body and zonule, previously hidden from clinical observation, can be imaged and their morphology assessed. Additionally, pathophysiological changes involving anterior segment architecture can also be evaluated qualitatively and quantitatively. This chapter will review the various applications of the UBM for glaucoma and illustrate how it can be a useful tool in the management of various conditions.