Besides the relapse rate and neurological examination, magnetic resonance imaging (MRI) plays a key role in multiple sclerosis (MS) monitoring. However, MRI is costly and even in Germany not always readily available. Additionally, routine MRI scans are not sensitive enough regarding differentiation between demyelination and neurodegeneration and show a discrepancy between lesion load and the degree of disability. In contrast, optical coherence tomography (OCT) is a validated non-invasive method for the quantification of neurodegenerative processes in the retina, as they appear in MS and other neurological diseases. The OCT is inexpensive, easy to handle and highly reproducible. Additionally, it is well tolerated and thus represents a promising tool for monitoring of neurodegenerative disorders. This article describes in detail the OCT technique and its usefulness for both diagnosis and monitoring of MS.