Eye-twitching might be necessary for seeing

July 30, 2007

By Flinn Foundation

[Source: Robin Moroney, WSJ] — Researchers might finally have explained an oddity about eyesight that has flummoxed scientists for decades: why eyes seem to twitch involuntarily, Scientific American reports (subscription required). Those frequent flickers were once thought to be random, but now scientists say that the process could be essential for observing stationary objects. Since the 1800s, scientists have observed that when people deliberately focus on a stationary image, other parts of the image seem to fade away.

In recent decades, scientists have begun to suspect that human eyes make imperceptible movements as a way of adapting to the challenge of seeing stationary objects. Susana Martinez-Conde and Stephen Macknik, both of the Barrow Neurological Institute in Phoenix, write how recent experiments suggest that the largest of the eye