Constant small movements of the eye may have a more serious purpose than has been previously thought, according to new research.
In a study published in the journal Science, by Drs Richard Krauzlis and Ziad Hafed of the Salk Institute of California, it was found that the flickering movements made even when a person is trying to watch something steadily may be a means of preventing blindness.
Rather than simply being caused by nerve signals, as has been previously believed, the study found that these involuntary movements cause images on the retina to be repeated, thus preventing them from fading.
The movements are called "microsaccades".
Dr Hafed explained: "Because images on the retina fade from view if they are perfectly stabilised, the active generation of fixational eye movements by the central nervous system allows these movements to constantly shift the scene ever so slightly, thus refreshing the images on our retina and preventing us from going "blind"."
The Salk Institute, which has more than 850 scientific staff, was set up by Dr Jona Salk, inventor of the vaccine for polio.
He intended that biologists should be able to develop research and discovery.
by Adrian Galbreth