To describe a cerebellar peduncle ischemic stroke associated with reversal of vision metamorphopsia and visual hallucinations.

Reversal of vision metamorphopsia (RVM) is a rare visual phenomenon described as an upside-down, 180-degree rotation of the visual field in the coronal plane. RVM has been reported in brainstem and cerebellar strokes, multiple sclerosis, migraines, seizures, and conditions that interrupt the peripheral vestibular system such as Meniere’s disease. Another rare form of visual perception dysfunction from a posterior circulation stroke is peduncular hallucinosis, which has been described as vivid, colorful visions of people and animals. RVM and visual hallucinosis are both thought to be transient conditions. The pathophysiology of RVM and peduncular hallucinosis remains unclear.

Case report

An 80-year-old man presented to the emergency department with acute onset dizziness, imbalance, reversal of vision metamorphopsia, and well-formed visual hallucinations of people, animals, and fire. MRI brain demonstrated an acute ischemic stroke in the inferior edge of the right cerebellar peduncle. EEG did not show any epileptiform activity. Visual hallucinations resolved by the time of discharge without any interventions, further supporting peduncular hallucinosis as the etiology. At follow-up, he denied further episodes of visual hallucinations, and RVM had improved significantly.