In the middle of the 20th century, an Austrian professor turned a man’s eyesight exactly upside-down. After a short time, the man took this completely in his stride.
Professor Theodor Erismann, of the University of Innsbruck, devised the experiment, performing it upon his assistant and student, Ivo Kohler. Kohler later wrote about it. The two of them made a documentary film.
The professor made Kohler wear a pair of hand-engineered goggles. Inside those goggles, specially arranged mirrors flipped the light that would reach Kohler’s eyes, top becoming bottom, and bottom top.
At first, Kohler stumbled wildly when trying to grasp an object held out to him, navigate around a chair, or walk down stairs….
So begins this week’s Improbable Research column in The Guardian.