Marius Hans Erik Tscherning (11 December 1854, in Østrup near Odense – 1 September 1939) was a Danish ophthalmologist.
Tscherning spent 25 years at the Sorbonne, where he worked closely with Louis Émile Javal (1839–1907).
He conducted research of entoptic phenomenon, Purkinje images, the etiology of myopia, and Listing's law of ocular movement.
[1] He also designed an ophthalmophacometer, a device used to measure changes that happen in the front and back curvatures of the lens during accommodation.
[3] Tscherning was the author of over 100 scientific articles, including a book titled Optique physiologique, published in 1898 in Paris by Garré and Naud, and was later translated into English (Physiologic optics), and Hermann von Helmholtz et la Théorie de l´Accommodation, Paris 1909 Octave Doin, ("Hermann von Helmholtz and the Theory of Accommodation") which was critical to Helmholtz's work on the same subject, published in the Graefe's Archiv (volume 1, 1854).