Primer on Optical Coherence Tomography for the Neurologist

Abstract Purpose of Review This review describes applications of optical coherence tomography (OCT) in the diagnosis, follow-up, and surveillance of common neurologic conditions. Recent Findings OCT obtains reproducible scans of the ocular fundus with near-cellular level resolution. Most importantly, OCT can measure the macular ganglion cell complex (GCC) and retinal nerve fiber layer (RNFL) around the optic nerve. Measured changes to these layers correlates with visual field defects and with visual pathway lesions. Analyzing these layers provides insight into the impact, extent, and evolution of brain lesions including strokes and intracranial masses. Additionally, OCT can help distinguish and can monitor demyelinating diseases presenting with optic neuritis. When evaluating optic disc edema, OCT can monitor progression, detect clinically-inapparent changes, and can distinguish true edema from psuedopapilledema. OCT also may be applied to monitoring ischemic optic neuropathies and in early detection of neurodegenerative disease. OCT changes should be considered in context with neuroimaging, funduscopic findings, and clinical history, and the possibility of artifacts must be considered in interpreting OCT data. Summary Continued improvements in OCT have made it increasingly useful for diagnosing and monitoring CNS disease. Neurologists, working with ophthalmologists, should use this powerful tool in practice to improve diagnosis and surveillance and to help guide treatment of neurologic disease.