Anterior Segment Optical Coherence Tomography

Abstract

Anterior segment optical coherence tomography (AS-OCT) is a noncontact in vivo imaging method that provides qualitative and quantitative assessments of the anterior segment and its anatomical structures, including the iridocorneal angle and aqueous outflow pathways. Advances in optical coherence tomography (OCT) technology revolutionized ophthalmology, and AS-OCT imaging has rapidly matured into a versatile tool for clinical examinations and scientific research. AS-OCT imaging provides a complement to gonioscopy and ultrasound biomicroscopy in assessments of the iridocorneal angle, an important anatomical site for evaluation in patients with elevated intraocular pressure. Modern AS-OCT devices can also characterize aqueous outflow structures within the scleral wall, such as the trabecular meshwork, Schlemm’s canal, and collector channels. AS-OCT imaging is of particular interest to glaucoma specialists for its use to assess biometric risk factors for gonioscopic angle closure and primary angle closure disease. It has also been used to evaluate and quantify patient response to laser or surgical treatment. Despite these technological advances and clinical applications, widespread adoption of AS-OCT imaging among eye care providers has been slowed by a variety of factors that limit its method and implementation. However, ongoing research is focused on resolving these limitations, which would greatly enhance the clinical utility of AS-OCT imaging in the future. This chapter discusses these topics and provides an introduction to qualitative and quantitative interpretation of AS-OCT images.