Hacking the Optic Nerve: The Persistent Glitch of the McCollough Effect: Colors, Grids, and the Bizarre Neurological Illusion That Can Last for Months

Most optical illusions vanish the second you look away. If you stare at a red dot and look at a white wall, you see a green afterimage that fades in seconds. The McCollough Effect, however, is a terrifying exception. It is a visual glitch that physically rewires your brain, and it can last for over three months.

If you spend a few minutes staring alternately at horizontal red lines and vertical green lines, your visual cortex forms a maladaptive association. Afterward, when you look at a com...