Johann Friedrich Horner (27 March 1831 – 20 December 1886) was an ophthalmologist based at the University of Zurich, Switzerland.
After receiving his medical degree from the University of Zurich in 1854, Horner continued his studies in Vienna and Berlin. While in Berlin, he was an assistant to the renowned ophthalmologist Albrecht von Graefe (1828-1870). It was during this time that Horner decided to become an ophthalmologist himself. He returned to Zurich in 1856, and later opened his own eye clinic named Hottinghof.
Horner became a full professor of ophthalmology in 1873. After his death in 1886, his position at the University of Zurich was filled by Otto Haab (1850-1931).
Horner's syndrome, a disorder of the sympathetic nervous system, is named after him, following his description of the condition in 1869. His name is also associated with "Horner's muscle", which is the lacrimal portion of the orbicularis oculi muscle, and sometimes known as the "tensor tarsi muscle".[1] In his career, Horner published approximately 40 papers on eye disorders.