Joseph Hasner, Ritter von Artha (13 August 1819 – 2 February 1892) was an Austrian ophthalmologist born in Prague.
His brother, Leopold Hasner von Artha (1818–1891), was an influential Austrian politician.
He studied medicine at the University of Prague, and subsequently worked at the local general hospital (1842).
Hasner is remembered for the discovery of plica lacrimalis, which is a fold of mucous membrane that guards the lower opening of the nasolacrimal duct.
Also, he put forth the theory that myopia was caused by stretching of the eyeball — this being due to pulling on the posterior pole by the optic nerve.