To report a case of atypical Miller Fisher syndrome with pupil involvement.

An 18-year-old woman visited our clinic with a headache and blurred vision. Ophthalmic examination revealed a corrected visual acuity of 20/20 in both eyes, with both pupils dilated to 7.5 mm. There was a loss of light reflex and near reflex in both eyes. Ocular motor examination revealed bilateral abduction, and supraduction limitation, and mild adduction limitation. Neurological examination demonstrated hyporeflexia without ataxia. Brain CT, brain MRI, nerve conduction test, CSF study, and thyroid function tests were normal. The serologic anti-GQ1b IgG test was positive.

We confirmed a case of atypical Miller Fisher syndrome with an anti-GQ1 antibody test that had pupil involvement, areflexia, and acute ophthlamoparesis.