Acute Visual Loss Secondary to Arnold Chiari Type I Malformation Completely Resolving After Decompressive Posterior Fossa Surgery.

We describe the case of a 22-year-old woman of southeast-Asian origin, presenting with unilateral sudden visual loss after a self-healing hearing loss a week before. Ophthalmological examination showed visual acuity of light perception in the left eye, mild RAPD, normal ocular motility and an elevated optic disc with indistinct margins. Neurological examination showed no acute pathology and brain CT-MRI imaging revealed a small-almost subclinical-herniation of the cerebellar tonsils.