When we stare at something a computer or TV screen, for example we have the sensation that our eyes aren't moving. But it turns out that nothing could be further from the truth.
New research by Boston University professor of psychological and brain sciences Dr. Michele Rucci, published in the journal Current Biology, demonstrates that our eyes are moving pretty constantly and that's a good thing.
This research focused on eye movements that occur when the head is allowed to move naturally, which distinguishes it from other such studies in which the head is artificially restrained. Dr. Rucci and colleagues found that both the eyes and the head are constantly moving, but the movements small enough such that the movements are not apparent: they are "micro movements." They also found that the eye movements, which are called fixational eye drifts, seem to compensate for the head movements: that is, they are not just random movements.
Not only are these movements compensatory, they also function to enhance the acuity, or sharpness, with which we see. Dr. Rucci says that if the eyes and head are prevented from moving, the image we see will actually fade away. That is, we need these micro movements to help the sensitive nerve cells of the retina reconstruct a scene, to gather information about an image from more than one viewpoint. He notes that it seems that these tiny eye movements help to reformat the image on the retina, which then transmits it to the brain.
This new "take" on the importance of micro movements certainly will help inform our understanding of the process of vision. Perhaps it will also, at some future point, give us the ability to better treat some visual disturbances and diseases.