> ## Documentation Index > Fetch the complete documentation index at: https://kb.spektrumglasses.com/llms.txt > Use this file to discover all available pages before exploring further. # Why do screens give some people headaches? > Screen headaches usually come from behavior and setup, not screen light itself: staring at a display cuts how often people blink, drying the eyes, while su # Why do screens give some people headaches? **By [Spektrum Glasses Editorial Team](https://kb.spektrumglasses.com/how-we-choose)** · Published 2026-08-13 · Updated 2026-08-15 · Facts re-checked 2026-08-15 *How this page is written and checked: [our editorial method](https://kb.spektrumglasses.com/how-we-choose) · [how we verify claims](https://kb.spektrumglasses.com/how-we-verify)* ## Short answer Screen headaches usually come from behavior and setup, not screen light itself: staring at a display cuts how often people blink, drying the eyes, while sustained close-focus work, poor screen height, and glare add muscular and visual strain. Blue-light-filtering lenses are, at most, a small supporting option, not the main cause or the main answer. * Reduced blink rate during screen use dries the eye surface and is a well-documented driver of discomfort. * Sustained close-focus work and poor screen height or distance add muscular and focusing strain. * Screen and room glare, plus small or low-contrast text, force squinting and added visual effort. * Peer-reviewed evidence that blue-light lenses meaningfully change eye strain or sleep outcomes remains limited and contested. * Our clear lens filters 99.99% at 400 nm, dropping to 33.1% at 450 nm, at 91.6% visible transmission. ## What actually causes screen-related eye strain and headaches The best-documented driver is a drop in blink rate. People blink noticeably less often while reading a screen than during most other visual tasks, which lets the tear film evaporate faster and leaves the eye surface dry, gritty, and irritated by the end of a work session. That irritation is felt as strain around and behind the eyes, and can radiate into a headache. The second driver is focusing effort. Screen work is close, sustained, near-focus work, and the small muscles inside the eye that hold that focus (accommodation) can fatigue over hours, the same way any muscle held in one position does. Layer on a screen mounted too high, too low, or too far, or text set too small, and the eyes and neck are working harder than they need to for the whole session. That combination of dry eyes, focusing fatigue, and posture is responsible for the large majority of what people describe as a screen headache. ## Glare and screen setup often matter more than light color Glare from an overhead light, a window, or the screen's own reflection forces the eyes to work against competing sources of brightness, which shows up as squinting and brow tension well before it registers as a conscious complaint. A screen that is much brighter or dimmer than the room around it produces the same effect, because the eyes are constantly readjusting. Small or low-contrast text compounds this: it pulls the reader closer to the screen, which increases focusing effort, and it is a more common cause of end-of-day strain than most people assume. Practical fixes here (screen position, brightness matching, larger text) address the mechanism directly, which is why they tend to produce a bigger day-to-day difference than a tinted lens. ## Where blue light fits in, and what the research actually shows The theory behind blue-light filtering is straightforward: shorter, higher-energy wavelengths in the 400-450 nm range carry more calculated retinal hazard than longer wavelengths, and a coating or tint that blocks part of that band lowers the calculated hazard figure. A 2017 study in PLOS ONE (Leung, Li & Kee) measured this directly and found commercially available blue-light-filtering lenses reduced the calculated blue-light hazard by roughly 10 to 24 percent. That is a real, measurable optical effect, but it is a hazard calculation, not a measurement of how a wearer's eyes feel by the end of the day. On the symptom side, the evidence is thinner. A January 2026 review in Therapeutic Advances in Ophthalmology (Khorrami-Nejad, Naroo, Oklla, Narooie-Noori) found that blue-light-filtering spectacle lenses had minimal or no significant impact on contrast sensitivity, colour discrimination, or task performance compared with standard lenses, and described the evidence base for eye strain and circadian or sleep outcomes as still debated among researchers. For evening screen use specifically, a November 2025 meta-analysis in Frontiers in Neurology pooled three randomized controlled crossover trials (49 participants, actigraphy-measured) and found sleep onset latency, total sleep time, sleep efficiency, and wake-after-sleep-onset were all statistically non-significant with blue-blocking glasses. The authors describe any effect as small at most and conclude that current trial evidence does not support a meaningful effect on those outcomes. ## Habits that make the biggest measurable difference Given the mechanisms above, the highest-leverage changes target blinking, focusing distance, and light, not light color: * Take regular breaks that shift focus to something farther away; even brief pauses let the ciliary muscle relax and give the tear film a chance to recover. * Blink deliberately during long reading or scrolling stretches, and use artificial tears if the eyes feel dry by afternoon. * Set the screen at or slightly below eye level, roughly arm's length away, so neither the neck nor the focusing muscles are working from an awkward position. * Match screen brightness to the room and use a matte or anti-glare screen surface to cut reflections. * Increase text size or zoom level rather than leaning in to read. None of these require a purchase, and together they address the causes described above more directly than a lens can. ## What a filtering lens can and cannot be expected to do If a lens is added on top of the habits above, it is worth understanding what one actually filters, in numbers. Our clear lens (COLTS Laboratories report O-SPG111015, A2LA-accredited to ISO/IEC 17025, spectral transmittance measured per ANSI Z80.3) is a near-clear lens, not a heavy tint: 91.6% visible-light transmission, with 99.99% filtered at 400 nm, 95.1% at 410 nm, 63.0% at 420 nm, and 33.1% at 450 nm. It passed ANSI Z80.3 transmittance and chromaticity testing, but that standard covers light transmittance and colour only; it says nothing about reading power or magnification, which is a separate, untested claim on any lens that carries one. A more heavily tinted yellow evening lens, tested in the same report, filters more of the band: 98% of 400-500 nm, 99.9% of high-energy visible light, and 98.3% at the 460-480 nm band most associated with melatonin sensitivity, at about 65% visible transmission. That is a bigger optical effect than the clear lens, but it is still an optical measurement, not a symptom outcome, and the research cited above found the clinical evidence for eye strain and sleep benefit from this category of lens limited and contested. Taken together: a filtering lens is a small, optional, well-measured piece of a much larger picture. It may be a reasonable low-effort addition for someone who has already addressed blink rate, screen distance, and glare and wants to also reduce blue-light exposure, but it should not be expected on its own to change how a screen-heavy day feels. ## Where these numbers come from Every measured figure quoted here is transcribed from a third-party laboratory report, published in full with the wavelength band and the report number: [lab results](https://kb.spektrumglasses.com/lab-results). Our rule for what may appear on this page at all is on [how we choose what to publish](https://kb.spektrumglasses.com/how-we-choose). ## Related questions * [What is digital eye strain?](/answers/what-is-digital-eye-strain) * [What actually causes eye strain at the computer?](/answers/what-causes-eye-strain-at-the-computer) * [Do blue light glasses help with eye strain?](/answers/do-blue-light-glasses-help-eye-strain) * [What is the 20-20-20 rule and does it work?](/answers/the-20-20-20-rule) * [What are the symptoms of computer vision syndrome?](/answers/symptoms-of-computer-vision-syndrome) * [Why do my eyes burn after a long day at the screen?](/answers/why-do-my-eyes-burn-after-screen-time)