We are not aware of it, but we blink about 11,000 times a day . Optometry experts at the University of Waterloo in Canada estimate that, on average, we do it 12 to 17 times every minute. If every few seconds our vision is interrupted, even momentarily, why is it not limited to a succession of moments of darkness and light?
Now, an international team of researchers from different institutions coordinated by Gerrit Maus, from the Department of Psychology at the University of California, Berkeley, and Nanyang Technological University, in Singapore, has found that when we blink, our brain is in charge of stabilizing our vision . To do this, adjust our eyes, so that we continue to focus on what we are observing.
In a study published in the journal Current Biology , Maus and his collaborators point out that, while the blink lasts, our eyeballs move and do not always return to the same position they occupied when we open our eyes again. If this happens, our brain is responsible for activating the muscles of the eye and, thus, rearranging our vision.
To determine this, a dozen people participated in what Maus has called “the most boring experiment ever.” The volunteers had to sit in a dark room for long periods of time. All they could see was a point on a screen as they were recorded by infrared cameras that followed the movements of their eyes. Each time they blinked, the dot moved one centimeter to the right. The study participants were unaware of this, but their oculomotor system sensed the subtle displacement and adjusted their vision. After about thirty blinks, it was happening automatically.
Scientists emphasize that our brain does not stop making predictions in order to compensate for our movements . “We are equipped with rather slow and imprecise eye muscles, so the brain must constantly adapt its motor signals to ensure that our eyes always point where they should,” says Maus. “In essence, it compensates for the difference in what we see before and after the blink by ordering the eye muscles to make the necessary corrections.”
