OCT in Glaucoma Diagnosis, Detection and Screening

Abstract

Glaucoma is a chronic and progressive optic neuropathy in which increased intraocular pressure is the most important risk factor in the etiopathogenesis. The basic pathology is the progressive loss of retinal ganglion cells (RGCs) especially the death of the axons of ganglion cells initially (apoptosis), followed by peripapillary retinal nerve fiber layer (RNFL) defects. Since optical coherence tomography (OCT)’s first demonstration in 1991 by Huang et al. and introduction commercially in 1996, it began gaining popularity in 2000s for retinal evaluation and the detection, diagnosis, and follow-up of glaucoma. Previously available OCT instruments used a technique referred to as time-domain (TD-) OCT, followed by spectral-domain (SD-) OCT, which has an increased scan acquisition rate, allowing for a more detailed sampling of the area of interest. Recently, swept-source OCT (SS-OCT), a newer generation of OCT, has been introduced. Clinical assessment using multiple parameters, including peripapillary RNFL, ganglion cells, optic nerve head, and macular parameters, has proven useful for managing and diagnosing glaucoma as well as for evaluating risk in glaucoma suspects. In this chapter, we aim to evaluate the use of OCT and its modalities in diagnosis, screening, and progression of glaucoma.