Marius Tscherning

Who was Marius Tscherning?

Marius Hans Erik Tscherning was a Danish ophthalmologist.

He studied ophthalmology under Edmund Hansen Grut in Copenhagen, later becoming an adjunct director at the ophthalmological laboratory at the Sorbonne in Paris. Tscherning spent 25 years at the Sorbonne, where he worked closely with Louis Émile Javal. In 1910 he returned to Denmark as a professor at the University of Copenhagen and head of the ophthalmic department at the Rigshospitalet.

Tscherning is remembered for contributions made in optical physiology. He conducted research of entoptic phenomenon, Purkinje images, the etiology of myopia, and Listing's law of ocular movement. He also designed an ophthalmophacometer, a device used to measure changes that happen in the front and back curvatures of the lens during accommodation.

He is probably best known for his theory regarding the mechanism of accommodation, of which he disagreed with the accommodation theory proposed by Hermann von Helmholtz.