Sir, A 49-year-old Chinese woman presented with blurred vision in both eyes 2 months before admission. She was unable to cut vegetables and cook food due to above clinical symptoms. She had no remarkable past medical history and family history. She visited Department of Ophthalmology in a local hospital, suggesting reduced visual acuity and no abnormalities in the fundus and intraocular pressure. She could only see objects in front of her eyes as the clinical symptom of blurred vision rapidly worsened. The patient experienced dizziness 1 month before admission, relieved by closing eyes and accompanied by unsteady walking. Vestibular function examination was performed, and bilateral upbeat nystagmus was observed by position tests (Dix-Hallpike and roll test). She received repositioning treatment, but it was ineffective.