Visual displays that inadvertently suppress the release of melatonin, such as in smartphones, televisions, and computer screens, can be redesigned to give us all a well-earned rest, say scientists from the Universities of Manchester and Basel.

The team led by Rob Lucas, BSc, PhD, and Annette Allen, BSc, MRes, PhD, from The University of Manchester recently unveil technology that could impact displays in televisions, smartphones, projectors, computer screens, and tablets.

The researchers, who published their European Research Council-funded study in the journal Sleep, say the technology could also mean that night workers are less likely to fall asleep at a computer.

The device—which the researchers call a “melanopic display”—allows users to control the alerting effects of screen use and can also enhance the visual appearance of screens, say the team.

The technology allows the amount of cyan light in images to be altered while keeping colors true.

Conventional display is made up of red green and blue primary colurs, which match up with three types of photoreceptors in our eyes. The team added a fourth “primary color” (cyan), which controls melanopsin cells in the eye that detect light, normally in the daytime. When the cyan light was turned up, the 11 participants in the trial felt more alert; when turned down, they felt more sleepy.

They watched a movie produced with or without the cyan primary, rating how sleepy they felt afterwards and producing saliva samples for the team to measure levels of melatonin.

Participants felt more alert when exposed to cyan light and sleepier when the cyan was dimmed even though colours looked the same. Melatonin levels in their saliva were also higher when cyan was turned down.

“This outcome is exciting because it that tells us that regulating exposure to cyan light alone, without changing color, can influence how sleepy we feel,” Lucas says in a release. “Our study also shows how we can use that knowledge to provide a next generation of visual displays. We built our melanopic display by adapting a data projector, but we would expect that this design could be applied to any type of display. Such displays could, for example, help phone obsessed teenagers to fall asleep or support alertness in people who need to use a computer at night.

Allen says, “The new display design could actually have a wider benefit, as it seems that this technology also improves image appearance. Like adding salt to food, we aren’t necessarily aware that it’s been done though we appreciate the effect.”