The human eye 'refreshes' constantly like an Internet web page, Italian researchers have discovered.
An all-Italian team at the University of Boston say they can now explain why the eye-ball never stops flickering - a phenomenon first noted in the 1950s.
The researchers believe the discovery can be used to help find a cure for congenital eye problems which impair vision.
The almost imperceptible movements are necessary for the eye to keep track of moving images, according to team leader Michele Rucci.
Speaking to ANSA after the publication of the team's work in the scientific journal Nature, Rucci said: "We aren't aware of it but our eyes are continually in motion, in such a way that the images on the retina keep moving too".
In an experiment, Rucci's team managed to block these eye movements in a group of volunteers.
They found that they could no longer make out the fine detail of images.
"The fact is that the eye needs moving images which are constantly refreshed in order to be able to see properly".
