Blue light filters have been popular for many years; they used to be limited to PC apps and web browser extensions, but have since become standard features on mobile devices. There are multiple purported benefits to using blue light filters, including reduced eye strain and getting better sleep at night. Past research has cast doubt on the latter claim, and a new study backs up those findings.
The new study comes from Brigham Young University, where researchers tested the Night Shift feature available on iOS to see whether it had any impact on sleep quality — though, mind, Apple lists this feature as a way to reduce eye strain, not improve sleep. Likewise, a number of Android phones and tablets also feature their version of a blue light filter setting.
The research involved three different categories of participants: those who used their iPhone at night with the Night Shift feature turned off, those who used it at night with the feature turned on, and people who didn’t use a smartphone at all before going to bed.
A total of 167 adults ages 18 to 24 were tracked using an accelerometer while they slept to monitor their activity. A phone-monitoring app was also used with the participants who were told to use their phones before going to sleep. After looking at the data on things like how often they woke up after falling asleep, their sleep quality, and how long it took to fall asleep, the study found no differences between the three groups.
After splitting up the participants into two groups — those who got less than six and those who got seven or more hours of sleep a night — the study found that phone usage was linked to a ‘slight difference’ in sleep quality. It was the non-phone group that enjoyed ‘superior sleep quality,’ however. Night Shift use or lack thereof didn’t influence the sleep results despite using a phone before bed, however.