The Study
Effect of evening blue light blocking glasses on subjective and objective sleep in healthy adults: A randomized control trial.
This study is like a small experiment that tried to see if special glasses that block blue light help people sleep better. It found that people *felt* like they fell asleep faster when wearing them, but their actual sleep, measured by a device, didn’t really change.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Adults wore yellow glasses that block blue light in the evening for one week and clear glasses another week. They wrote down how they felt about their sleep and wore a sleep watch to track it.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 546 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The small improvements in how people felt about their sleep may not matter much in real life, especially since actual sleep time didn’t improve and may have gotten slightly worse.
- 2People said they fell asleep a little faster (21 vs 24 minutes) and woke up less (1.6 vs 2.2 times).
- 3But the sleep watch showed no real improvement.
- 4Surprisingly, people slept slightly less when wearing blue light glasses—about 12 minutes less by diary, 16 minutes less by watch.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Sleep health
Year
2021
Authors
Jeremy A. Bigalke, Ian M. Greenlund, Jennifer R Nicevski, J. Carter
Related Content
Claims (4)
Wearing blue light blocking glasses after 6 PM for a week doesn’t actually help healthy adults sleep longer or more soundly, according to wrist-worn sleep trackers.
Wearing blue light blocking glasses might actually make some people sleep a little less, even though they’re supposed to help. Both how people felt and sleep tracker data showed slightly shorter sleep, but the difference wasn’t strong enough to be sure it wasn’t just chance.
Wearing blue light blocking glasses every evening for a week might help healthy adults fall asleep a little faster and wake up less during the night.
Being around blue light at night, like from phones or screens, might keep your body from making the sleep hormone melatonin because it keeps stress hormone levels high, making it harder to fall and stay asleep.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.