Miller-Fisher syndrome (MFS) is considered a variant of Guillain-Barré syndrome (GBS). The syndrome
is characterized by acute onset of gait ataxia, ophthalmoplegia, and areflexia. Conventionally, MFS
has been considered exclusively a disease of the peripheral nervous system. However, there are occasional
reports of central nervous system involvement. Here, a 62 year-old woman who presented with classical
features of MFS and progressive bilateral dyschromatopsia and reported visual impairment. Normal MRI of
the brain and CSF albumino-cytologic dissociation were observed. CSF oligoclonal IgG pattern indicated a
passive transfer of oligoclonal IgG from a systemic inflammatory response. Nerve conduction studies showed
slow motor conduction velocity in her extremities. The optic fundi were normal. Visual evoked potentials
(VEPs) revealed bilateral optic neuropathy. Marked spontaneous improvement of her syndrome was documented
within six weeks. Optic neuritis may be a central nervous system feature that should be recognized as
part of the MFS.

Keywords: Miller-Fisher syndrome, Optic neuritis