Body Handbook კატალოგი პროფილი რეიტინგი
სინათლე BODY HANDBOOK
სინათლე · §475
Blue Light Filtering
The clear-lens "blue light glasses" sold by optical chains block about five to fifteen percent of the wavelengths that matter, and the largest pooled review found they do nothing for tired eyes Singh et al. 2023. One narrow version does work: true amber lenses, worn for a couple of hours before bed, help you fall asleep faster. Everything the marketing sells splits into that one real use and four that aren't. Buy the right thing and you drop off ten to thirty minutes sooner.
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Two separate stories get sold as one. A handful of cells at the back of your eye don't help you see; they tell your brain whether it's day or night, and they're tuned to short-wavelength blue around 480 nm 1. Blue reaching them in the evening suppresses the melatonin that should be rising for sleep, and it scales with brightness, not just color 2. Eye strain is a different problem entirely: blinking less and holding one focal distance for hours 3. Filtering the screen does nothing for it.

Real amber lenses shift sleep; software and clear lenses don't. Wear amber tint for the two to three hours before bed and you fall asleep a little faster and feel less wired at bedtime 4 5. People whose schedules had drifted late gained about 78 minutes 6. Night Shift, tested head-to-head, made no measurable difference — only putting the phone down helped 7. The trials are small and modest, so treat the size with humility.

The dimming does most of the work; the lenses add a little.

The bedtime ramp lifts first. Dim the house and wear real amber lenses before bed, and the wired-tired stretch where lying still feels worse than scrolling starts to give way to sleep actually landing — roughly ten to thirty minutes sooner 4 5. If your schedule runs late, more than that 6. Over a few weeks, mornings get easier. Your eyes feel no different, because that was never the same problem.

The fine print — when to skip it, and what people get wrong

Screen light doesn't damage the retina; sunlight is far more intense 8. Clear and amber lenses aren't the same product: clear ones block 5–15%, amber 90–99%. Night Shift doesn't make late phone use safe 7.

Don't wear amber lenses while driving — red and yellow signals blend and brake lights look weaker than they are. Same for color-critical work like design, photo editing, or radiology, where the screen has to stay accurate.

Clear lenses do nothing the trials measured. A bright bathroom LED undoes the dose in seconds. Warming the screen color doesn't lower its brightness, so drop that too. And the glasses cue the behavior; they don't replace it.

References
  1. 1Brainard GC, Hanifin JP, Greeson JM, Byrne B, Glickman G, Gerner E, Rollag MD (2001). Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor. Journal of Neuroscience. link
  2. 2West KE, Jablonski MR, Warfield B et al. (2011). Blue light from light-emitting diodes elicits a dose-dependent suppression of melatonin in humans. Journal of Applied Physiology. link
  3. 3Rosenfield M (2011). Computer vision syndrome: a review of ocular causes and potential treatments. Ophthalmic and Physiological Optics. link
  4. 4Heo JY, Kim K, Fava M et al. (2017). Effects of smartphone use with and without blue light at night in healthy adults: a randomized, double-blind, cross-over, placebo-controlled comparison. Journal of Psychiatric Research. link
  5. 5Shechter A, Kim EW, St-Onge MP, Westwood AJ (2018). Blocking nocturnal blue light for insomnia: a randomized controlled trial. Journal of Psychiatric Research. link
  6. 6Esaki Y, Kitajima T, Ito Y et al. (2017). Wearing blue light-blocking glasses in the evening advances circadian rhythms in the patients with delayed sleep phase disorder: an open-label trial. Chronobiology International. link
  7. 7Duraccio KM, Zaugg KK, Blackburn RC, Jensen CD (2021). Does iPhone night shift mitigate negative effects of smartphone use on sleep outcomes in emerging adults? Sleep Health. link
  8. 8American Academy of Ophthalmology (2021). Should you be worried about blue light? link
დაკავშირებული სახელმძღვანელოში (9)
ალტერნატივები
  • — Instead of filtering emitted blue light, an e-ink panel emits none in the first place.
დაკავშირებული
  • — Screen light near bedtime is the real sleep thief people blame on 'EMF.' Dim it or filter it; the radio waves aren't the problem.
  • — Blue light isn't the culprit here — filters do little for screen eye strain, despite the marketing.
  • — Warming and dimming the room beats blue-blocking glasses — it's brightness and timing, not just colour, that matter.
  • — Filtering screen light helps a little; making the room genuinely dark does far more for sleep.
  • — Amber lenses cut the evening light that suppresses your own melatonin — same goal as a tiny dose, dimming the day-signal to your clock.
  • — These pigments are your retina's built-in blue-light filter, blocking ~40% before it reaches the cells. The glasses try to do the same job.
  • — A lit screen at night is exactly what pushes your body clock later; a filter dulls the worst of it, but paper or e-ink sidesteps it entirely.
  • — Computer glasses help some screen users — but the blue-light-filtering part has surprisingly weak evidence behind it.
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