We probably do it every day but scientists have only now discovered a distinct new way in which we move our eyes.
The team from University of Tübingen in Germany assessed the eye movements of 11 participants using tiny wires attached to the cornea and with infrared video tracking.
They discovered a new type of eye movement that is synchronised with blinking and helps reset the eye after it twists when viewing a rotating object.
It is like avoiding tiny rotations of a camera to stabilise the image people perceive. People do not notice the eye resetting in this way because it happens automatically when they blink.
“We were really surprised to discover this new type of eye movement and it was not what we had anticipated from the experiment,” said lead author Mohammad Khazali.
“We had expected to find that another, already well-known type of eye movement is synchronised to blinking,” he added in a paper published in the journal eLife.
Although it is brief, blinking creates an interruption in our visual perception.
We spend up to a tenth of our waking hours blinking but hardly notice it.
It serves an essential role in lubricating the eye and may even provide the brain with small, frequent mental breaks.
The frequency and size of the movement is determined by how far the eyes have deviated from a neutral position.
It helps reduce strain in the eyes as they move to assess the world around us.
In further experiments, the scientists discovered that it even occurs when the eye is not tracking a rotating object.
“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,” Khazali added.