Ultrasound biomicroscopy in glaucoma

Ultrasound biomicroscopy (UBM) is a high-resolution ultrasound technique that allows noninvasive in vivo imaging of structural details of the anterior ocular segment at near light microscopic resolution and provides detailed assessment of anterior segment structures, including those obscured by normal anatomic and pathologic relations. We summarize UBM applications in glaucoma. In some cases UBM elucidates the mechanism of elevated intraocular pressure by showing the relationship between the peripheral iris and the trabecular meshwork. It can be used to study the causes of secondary glaucoma, for example, the pigment dispersion syndrome, lens-induced glaucomas, ciliary block, cysts, and solid tumors of the anterior segment. It can also assess the effects of various interventions such as laser iridotomy, trabeculectomy, and non-penetrating drainage surgery. Precise quantitative evaluation of the anterior chamber angle structures can help in diagnosis and management of various pathologies related to glaucoma.