Old and new in exploring the anterior chamber angle

Angle-closure glaucoma includes a number of entities with closed angle, elevated intraocular pressure, in association with optic nerve damage and visual field defects as common markers. These entities are characterized by irido-trabecular apposition, irido-trabecular synechiae or both. The angle configuration must be systematically checked at least one time in patients presenting with raised intraocular pressure or glaucoma. Gonioscopy represented for a long time the gold standard for clinically assessing anterior chamber angle structures and their configuration. However, the interpretation of gonio-scopic findings is subjective and only semiquantitative. With the development of new imaging techniques of the anterior segment, new analysis methods have also emerged. Ultrabiomicroscopy was the first method of analyzing the anterior segment and is still the only imaging technique for all anterior segment structures (especially the ciliary body). Another method is optical coherence tomography, a non-contact technique by which angle configuration can be assessed in a more rapid and less invasive manner. Recently developed Pentacam technology could represent in the near future a more quantitative, rapid and non-invasive screening tool which could allow early detection of angle closure glaucoma and narrow angle configurations by measuring a set of anterior chamber parameters. List of abbreviations: ACG -angle closure glaucoma, ASOCT-anterior segment optical coherence tomography UMB- ultrasound biomicroscopy (ultrabiomicroscopy), PAS-posterior angle synechiae ACD-anterior chamber depth, ACV-anterior chamber volume, PLI-periphery laser iridotomy.