The multifaceted career of Louis Borsch.

John Louis Borsch Jr, MD (1873-1929), was an ophthalmologist from Philadelphia who spent most of his career in France. During his lifetime he was probably best known as the inventor of the first fused bifocal lens, which was marketed very successfully as the Kryptok lens. He may be better known today for performing cataract surgery on Mary Cassatt (1844-1926), the American Impressionist artist, and on James Joyce (1882-1941), the Irish author. Little known, but remarkable, is his thesis for his second medical degree, Le Traitement Chirurgical de l'Astigmie (The Surgical Treatment of Astigmatism).