From Imaging the Brain to Imaging the Retina: Optical Coherence Tomography (OCT) in Schizophrenia

Abstract

Optical Coherence Tomography (OCT) is a noninvasive imaging method, which provides an in vivo image of the retina. It allows for quantitative measurements of retinal and macular thickness, including single-layer analysis. Because the retinal nerve fibre layer comprises the first axons of the visual pathway and is unmyelinated, it can be considered a unique anatomical model, which may provide insight into the pathophysiological processes of diseases with a neurodegenerative character. In fact, past OCT studies have emphasized the role of the visual pathway as an ideal structure for exploring neurodegeneration and have demonstrated the potential of the method as an instrument for longitudinally monitoring structural changes in neurological disorders such as multiple sclerosis. Progress in signal processing and advancements to the OCT technique enables the illustration of structural changes in the retinal layers in a quick, reproducible, and objective manner with a spatial resolution comparable to those of histological slices. Findings from computer-based magnetic resonance imaging analyses and neuropathological studies support the hypothesis of a degenerative component of certain psychiatric disorders such as schizophrenia. Studies in schizophrenia incorporating OCT are currently rare and have yielded further heterogeneous results. This article elucidates the method of OCT and the retina's role as a "window to the brain". Furthermore, in delineating the degenerative components of schizophrenia, we discuss the possible applications of OCT in the schizophrenia population.