Fisher Syndrome is a rare neurological disorder characterized by abnormalities in eye movements and muscle weakness that can affect the limbs and face. It is also known as ophthalmoplegia, ataxia, and areflexia (OPCA) syndrome, which describes the three core features of the condition. Other synonyms for Fisher Syndrome include Miller Fisher Syndrome, Bickerstaff Brainstem Encephalitis, and Guillain-Barre Syndrome. Miller Fisher Syndrome is considered a subtype of Fisher Syndrome and is often used interchangeably. Bickerstaff Brainstem Encephalitis is a more severe form of the disorder that affects the brainstem and causes additional symptoms such as altered consciousness and respiratory failure. Guillain-Barre Syndrome is another related disorder that can sometimes overlap with Fisher Syndrome.