A previously unknown type of eye movement was discovered by researchers at the University of Tübingen, in Germany, during an experiment where volunteers’ eye movements were followed using an infrared video eye tracking system.
The researchers were attempting to determine if a known reflexive movement known as torsional optokinetic nystagmus (tOKN) occurs at the same time as blinking. tOKN occasionally resets the torsional movement of the eyes, to avoid moving beyond the mechanical limits of the eye muscles. To this end, the eye tracking system monitored the subjects’ eye position as they followed a rotating pattern of dots.
What they found, though, was that this tOKN movement was imperfect, and did not completely reset the muscles as they continued to twist. At their mechanical limit, the eyes “untwisted” all at once, resetting the torsion. Since this happened at the same time as a blink, this discorvery was named BARM, or blink-associated resetting movement.
“To discover such a ubiquitous phenomenon in such a well-studied part of the human body was astonishing to us and we’re very grateful to the volunteers who took part in the study,” said lead author Mohammad Khazali.
Paper available online at: https://elifesciences.org/content/5/e16290
