What you've heard: Blue-blocking glasses protect your sleep from screens
Do blue light glasses work for sleep?
Mostly unsupported; skip the glasses unless a clinician suggests them for a specific sleep problem. Evidence grade: Strong that the evidence for the glasses is weak.
Published Updated
The "What you've heard" box in Chapter 7
Mostly unsupported; skip the glasses unless a clinician suggests them for a specific sleep problem
The evidence
A Cochrane review found that blue-filtering lenses may do nothing for eye strain from computer use, and could not say whether they help sleep, because the evidence was of very low certainty. Amber lenses showed mixed results, with a possible benefit in specific sleep or mood disorders. A National Sleep Foundation panel could not agree that the light from screens before bed harms sleep, and found that filtering blue light gave "only minimal improvements." Brightness and timing matter more than color, and dimming the room does the same job for nothing.9 Screens do disturb sleep in other ways, especially for children and teenagers (Chapter 12).
Where the book tests it
What the book recommends instead
Get outdoor daylight early in your day, roughly 10 to 30 minutes
ProbableEvidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials.How: within an hour of waking, step outside, not behind glass: walk part of the commute, coffee on the step, the dog. Longer when gray or shaded; open sky beats a courtyard; a lunchtime walk outside counts too. Sunglasses are fine. Why: morning light pulls the clock earlier, and outdoors is many times brighter than indoors.
Related claims
- Is mouth taping safe, and does it work?Unsupported, with a safety catch.Evidence grade: Emerging. Early, small, animal-only, or actively contested.
- Is sunscreen bad for you?Against: the one trial runs the other way.Evidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials.
- Does ten minutes of morning sunlight set your body clock?Right direction, invented number.Evidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials.
- Should you wait 90 minutes after waking for coffee?Untested, and the reasoning looks backward.Evidence grade: Emerging. Early, small, animal-only, or actively contested.
- Do tart cherry juice and magnesium help you sleep?Unproven.Evidence grade: Emerging. Early, small, animal-only, or actively contested.
- Can NSDR or yoga nidra replace lost sleep?A pleasant way to rest, not a substitute for sleep.Evidence grade: Emerging. Early, small, animal-only, or actively contested.
- Does a digital detox reset your brain?A planned break brings a small lift and can reset a habit; "resets your brain" is overstated.Evidence grade: Probable. Good observational evidence with a plausible mechanism, or small or few trials.
- Is screen time destroying a generation?Unproven as stated, with a serious case on both sides; heavy use is a fair worry, and the causal claim is open.Evidence grade: Emerging. Early, small, animal-only, or actively contested.
Everything on sleep and light · Everything on phones and attention
Sources
The "What you've heard" box in Chapter 7
- 9.Singh, S., Keller, P.R., Busija, L., McMillan, P., et al. (2023). "Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults." Cochrane Database of Systematic Reviews, 8(8), CD013244. https://doi.org/10.1002/14651858.CD013244.pub2 (Seventeen trials.) ; Shechter, A., Quispe, K.A., Mizhquiri Barbecho, J.S., Slater, C., et al. (2020). "Interventions to reduce short-wavelength ('blue') light exposure at night and their effects on sleep: a systematic review and meta-analysis." Sleep Advances, 1(1), zpaa002. https://doi.org/10.1093/sleepadvances/zpaa002 ; Hartstein, L.E., Mathew, G.M., Reichenberger, D.A., Rodriguez, I., et al. (2024). "The impact of screen use on sleep health across the lifespan: A National Sleep Foundation consensus statement." Sleep Health, 10(4), 373-384. https://doi.org/10.1016/j.sleh.2024.05.001
Note numbers are those of Chapter 7, Light and Dark.
This verdict is one of the "What you've heard" boxes in Chapter 7, Light and Dark, where the book tests the claims people repeat against the studies behind them. The grade rates the evidence behind the verdict, by the book's stated method.
Educational content, not medical advice. Disclaimer.