The Nyctalope is a lesser-known fictional superhero who appears in a series of novels written by French writer Jean de La Hire, a prolific author of popular adventure series, many of which include science fiction elements. Léo Saint-Clair is The Nyctalope, a crime fighter who can see in the dark with his eerie eyes whose irises shift colors. It is revealed later that The Nyctalope sports an artificial heart.
First appearing in 1911 (or 1908, if one consider Leo Saint-Clair’s father, Jean Saint-Clair), he’s the first superhero of the genre, followed by the Japanese Ogon Bat, Superman and Doc Savage in the 1930s and, later again, Batman in 1939.
(adapted from English and French Wikipedia entries)