New research shows that when our vision is blocked, our eyes are constantly adjusting and re-examining what we're seeing, and this can lead to a brief period of 'blindness'.
The research looks at the foveola, a tiny part of the eye. It's the foveola that we rely on to report back to the brain when we're looking for someone in a crowd or trying to see a road sign.
Our eyes make small and rapid gaze shifts called microsaccades when we're looking closely at something, and the new study shows how these microsaccades also temporarily disabling our vision.
Janis Intoy is a vision scientist from the University of Rochester in New York and the study's co-lead author.
The results show that the center of our gaze undergoes drastic and rapid changes when we change our gaze.
Good vision is dependent on how and when we shift our gaze, like rotating a telescope to get a clear view of your surroundings. The name saccadic suppression was given to the way the eye temporarily goes blind when looking to a computer screen.
The researchers wanted to know if the smaller gaze shifts worked the same way.
Six volunteers tried to look for a 'patch of fur' on a computer screen. The volunteers were looking at dots on a noise field background that looked like an animal's fur. The volunteers would press a button on the joypad if they saw a jump.
The participants were unable to see the digital fleas immediately before and after their gaze shifts, even though they were using a specialized eye scanner to record their foveolas.
The study doesn't do a lot to understand why this might be happening, but it is likely to be a way of keeping our vision stable. Experiments should be able to reveal more.
"This brief loss of vision likely occurs so that we don't see the world changing when we look at it," says Intoy. Our visual system is able to create a stable percept by suppressing perception during saccades.
Vision in the eye was improved after the saccade or rapid movement of the eye after the brief burst of blindness, according to the eye scanning.
These tiny moments of vision suppression happen so quickly that we're not aware that they're happening, and we're not aware of all the tiny gaze shifts that go on while we look at what's around us.
Thanks to highly precise scanning tools, we're able to get a close look at the mechanisms in our eyes, which can help scientists work out treatments and fixes when something goes wrong.
The University of Rochester has high-resolution tools in their lab that can be used to study vision at a small scale.
The research has been published.