Teens between the ages of 13 and 18 who use their phones an hour before they go to sleep have trouble getting to sleep, sleep less, wake up in the night and nod off during the day, research by public health institute RIVM has found.

The research, the first of its kind in the Netherlands, looked at the effects of looking at a computer or phone screen at night on the sleeping patterns of children and teens between eight and 18.

Some 22% of children (8-13) look at a screen daily at night. This shoots up to 83% for older teenagers. The average time spent watching a screen is two hours.

The group that looks at a screen most often or for long periods of time loses half an hour of sleep. After wearing glasses fitted with orange lenses to block blue light for a week teens’ sleeping patterns improved. The same happened when they stopped using their devices for a week.

The RIVM said the research proves that blue light, which is increasing because of new led technology, influences people’s biological clocks and affects normal sleeping patterns. Other factors include using screens late into the night which cuts in on sleeping time.

More research is needed to show if inbuilt blue light filters in devices could alleviate the effects on sleep, the institute said.