Researchers have discovered a switching mechanism in the eye that helps regulate sleep/wake cycles, while also revealing that the mechanism can be reversed. This allows normal sleep/wake patterns to be fully reversed, meaning nocturnal animals could become diunrnal (day active), and vice versa.

The findings show that light receptor cells in the eye are essential to setting rhythms of the brain’s primary timekeeper, the suprachiasmatic nuclei, changing previous understanding of how light input from the eye affects activity and sleep patterns.

“The significance of this research for humans is that it could ultimately lead to new treatments for sleep disorders, perhaps even eye drops that would target neural pathways to the brain’s central timekeeper,” says Susan Doyle, lead investigator from the University of Virginia.

The Proceedings of the National Academy of Sciences published the finding.