Multiple sclerosis (MS) is a common neurologic disorder with protean manifestations. The disease is characterized by myriad multifocal neurologic signs and symptoms, which tend to relapse and remit over the course of the illness. Some patients have a progressive course from onset (primary progressive) or develop progressive signs and symptoms over time (secondary progressive). It is not uncommon for patients with MS to present initially to the ophthalmologist with symptoms, including acute monocular visual loss (ie, optic neuritis), diplopia (eg, internuclear ophthalmoplegia, sixth nerve palsy), or oscillopsia (ie, nystagmus). No single test can be done to aid in either establishing a diagnosis of MS or ruling out MS. The diagnosis of MS is a clinical diagnosis supported by laboratory studies and neuroimaging findings. Early recognition of the disease is important because new immunomodulatory therapy is available that might slow progression of the disorder.