Why do we blink so often? (and perhaps too little?)

We don’t just blink to keep our eyes moist, according to research by the University of Rochester. We also close our eyes to see better.

We blink an awful lot. So much that our eyes are closed 3 to 8 percent of the time. And that’s quite strange. Every time we close our eyes, we cannot see anything for a short time. You would expect that we would prefer to do that as little as possible. Yet we blink more than necessary just to keep our eyes moist. The researchers of the University of Rochester decided to find out why.

They did this by using equipment used to measure eye movements, combined with computer modeling and spectral analysis. It turned out that closing your eyes gives a kind of signal that helps us to map out the bigger picture. Blinking is therefore much more than a moment when we see nothing or a break for the brain: it helps us to get a good picture of the world around us, even when we see nothing for a while.

Brightness and contrast
This is because the rapid closing and opening of the eyes changes the way light reaches our eyes. This temporarily improves the brightness and contrast of the visual information. This makes it easier for our brains to perceive details, especially in large, slowly changing images. Contrary to popular belief, the rapid movement of our eyelids actually improves vision rather than hindering it. “These findings challenge our traditional view of visual perception,” concludes Professor Michele Rucci, who led the study. “They show that blinking plays an active role in how we see the world around us.”

Quick update
The research also suggests that blinking also helps our brains to process visual information better. When we blink, we give our brain a kind of quick update with ‘fresh’ visual information. At the same time, the brain gets a short break to process that information. This allows us to focus better on which things are important in what we see. This works best for things that aren’t too detailed.

Yet sometimes we actually blink too little. We naturally blink a lot, but in the modern world with our screens and digital devices, we do that a lot less often than we should. This can cause tired or dry eyes and blurred vision. So maybe it’s not a bad idea to consciously blink more often every now and then, especially when you look at screens for a long time. Apart from that, it is always good to take regular breaks to rest your eyes.

Your eyes change location after you blink
When you blink, your eyeballs rotate to a slightly different position, and that is a conscious error. The misalignment forces the brain to activate and refocus the eye muscles. “Our eye muscles are quite slow and imprecise,” said lead author Gerrit Maus previously to Scientias.nl. “The brain continuously sends signals to ensure that the eyes look in the right direction. Our research shows that the brain measures the difference before and after blinking and then transmits the correct corrections to the eye muscles.”