In a recent article from the BBC, Prof Paul Gringras from Evelina Children's Hospital in London said "Smartphones, tablets and e-readers should have an automatic "bedtime mode" that stops them from disrupting sleep".
The doctor said, every new model is "bluer and brighter" and manufacturers need to show more "responsibility". As it gets darker in the evening, the body starts to produce the sleep hormone melatonin - which helps people nod off. Certain wavelengths of light, those at the blue-green end of the spectrum, can disrupt the system.
Gringras was part of a study that was published in Frontiers in Public Health, analysing the light emitted by devices. In the study, it concluded there was a clear trend for new devices to be bigger, brighter and emit more blue light.
Prof Gringras said, "There is converging data to say if you are in front of one of those devices at night-time it could prevent you falling asleep by an extra hour". There are some sleep devices that have been designed to reduce blue-green light emissions. A bedtime mode could filter out the blue light.
For more information on how to get a great night's sleep, visit our Sleep Matters page.