This essay connects Villiers de l'Isle-Adam's fantastic tale Claire Lenoir (1867/1887) and Gaston Leroux's detective story Le Mystère de la Chambre Jaune (1907) to contemporary debates in optical science. It argues that modern visual subjectivity is shaped less by photographic technologies than by new epistemological questions rooted in the anatomy of the eye. Both texts figure the retina as a troubled site of human knowledge through a link between domestic chambre and optical chamber: in Claire Lenoir, the purple-bordered wallpaper of Claire's hotel room exteriorizes the "retinal violet" of the eye's photochemistry, while in Leroux's tale, the central, mysterious "chambre jaune" reflects the retinal "tache jaune" debated in contemporary physiologies (AG)