Pathophysiology of optic neuritis

Acute optic neuritis is a common inflammatory optic neuropathy that is closely associated with multiple sclerosis (MS). As a clinical syndrome, optic neuritis typically presents with subacute visual loss and periocular pain that often resolve spontaneously. Optic neuritis is frequently the initial manifestation of MS, and also occurs commonly during the course of the disease. Not only does optic neuritis explain some of the visual disability experienced by MS patients, but it also provides unique insight into the pathophysiologic mechanisms underlying the MS disease process. Advancements in ocular and magnetic resonance imaging techniques have provided an exciting opportunity to interrogate optic neuritis as an in vivo model of inflammation, demyelination, and neurodegeneration in the central nervous system. In this chapter, we introduce the relationship between optic neuritis and MS, describe the clinical course of optic neuritis, and review its underlying pathophysiologic concepts.