Fixate the center dot. A purple letter flanked by other letters flashes in your peripheral vision โ identify it. Flankers get closer each round. 10 rounds.
Visual crowding is the phenomenon where an object becomes harder to identify when surrounded by similar nearby objects (flankers), even though it would be easy to recognize in isolation. Crowding is a major bottleneck for peripheral reading speed and is heavily studied in low-vision research.
Related tests: Peripheral Field Test or Peripheral RSVP Reading.