We spend up to a tenth of our waking hours blinking but hardly notice it and blinking creates an interruption in our visual perception.
We probably do it every day, but scientists have just discovered a distinct new way in which we move our eyes. The team assessed the eye movements of 11 subjects using tiny wires attached to the cornea and with infrared video tracking. In results published in eLife, they discovered a new type of eye movement that is synchronised with blinking.
‘Blink-associated resetting movement helps to reset the eye after it twists when viewing a rotating object and it happens automatically when we blink.’
The movement they discovered helps to reset the eye after it twists when viewing a rotating object. It is like avoiding tiny rotations of a camera to stabilise the image we perceive. We don't notice the eye resetting in this way because it happens automatically when we blink. "We were really surprised to discover this new type of eye movement and it was not what we had anticipated from the experiment," says lead author Mohammad Khazali.
"We had expected to find that another, already well-known type of eye movement is synchronized to blinking."
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 scientists sought to investigate whether a reflexive, involuntary eye movement called torsional optokinetic nystagmus (tOKN) occurs at the same time as blinking. The theory was that this reflex also creates a break in the visual system so synchronising them minimises downtime.
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Once they reached their maximum, the eyes reset so they were no longer twisted at all. This happened at the same time as blinking. The scientists have called this newly-discovered movement blink-associated resetting movement (BARM).
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The frequency and size of the movement is determined by how far the eyes have deviated from a neutral position. It helps to 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," says Khazali.
Source-Eurekalert