"Emma Bovary's eyes"

 Madame Bovary is the first published novel of French writer Gustave Flaubert. The protagonist is Emma Bovary, a disillusioned wife who indulges in extramarital affairs.

Flaubert famously changes Emma Bovary's eye colour several times throughout the text, variously suggesting her eyes are black, brown, and blue.

In Written on the Body, this reference is the first hint of many that the narrator may be unreliable, misremembering, or getting details confused.