[Young patient with acute monolateral amaurosis].

A 39-year-old patient presented with acute visual loss of the left eye. Although the initial ophthalmological and neurological examinations were uneventful, magnetic resonance imaging (MRI) showed optic canal narrowing and compression of the optic nerve secondary to a prominent posteriorly misplaced ethmoidal cell (so-called Onodi cell). Endonasal ethmoidectomy with decompression of the infected Onodi cell was performed. Microbiological testing showed growth of Haemophilus influenzae. Despite early surgical intervention vision could not be restored.