[Space perception: the history and its significance for art]

Some aspects of the opthalmologic history of Denmark are briefly mentioned. Lens extraction in 1667 in Copenhagen, Edmund Hansen Gruts stereoophtalmoscopy in 1857, Ludvig Panums area in 1858 (single vision) space perception and outside this area double vision), squint treatment, Marius Tschernings periscopic spectacle lenses, Henning Rønnes stereoortograph and keiroscope and Gerhard Rønnes stereoscope. Space perception depends mostly on binocular function (convergens), but in fact some space perception occurs in vision due to perspective, accommodation, parallaxe, blurring, colours and shadows. The Danisk Poet, Hans Christian Andersen, has in his novels mentioned latent squint. The German poet Rainer Maria Rilke was much interested in perspective in connection with the development of impressionism, especially Paul Cézanne. Rilke in his later period developed the view that concentration on perspective removed those essential aspects from the world, in which he found God or a fourth dimension, as exemplified in the presence of ghosts.