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What percentage of blue light should glasses block?

By Spektrum Glasses Editorial Team · Published 2026-08-15 · Updated 2026-09-11 · Facts re-checked 2026-09-11 How this page is written and checked: our editorial method · how we verify claims

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Short answer

There is no regulatory or clinical target percentage for how much blue light glasses should block. Lenses are tested by wavelength band, not a single number: our clear lens filters 33.1% at 450 nm and 91.6% visible light passes through, while our yellow evening lens filters 98% of the 400-500 nm band. A higher percentage has not been shown to produce proportionally larger measured benefit in controlled research.

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No regulatory or clinical threshold exists

No standards body publishes a required blue-light-blocking percentage for eyewear, so any number on a package is a manufacturer’s own reporting choice, not a certification. Our clear lens passed ANSI Z80.3 transmittance and chromaticity testing (filter category 0, cosmetic lens) in COLTS Laboratories report O-SPG111015, an A2LA-accredited lab (accredited to ISO/IEC 17025). But ANSI Z80.3 governs visible-light transmittance and lens color, not a blue-light-specific filtering minimum, and it does not test or certify the accuracy of a reading-magnification power. A lens can legitimately be called ANSI-tested on those grounds while still filtering almost nothing at some wavelengths and nearly everything at others. Because there is no target to hit, two lenses with very different real-world filtering can both market themselves as “blue light blocking” without technically lying. That is exactly why the number by itself is not useful for comparison.

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A percentage means nothing without its wavelength band

Blue light spans roughly 400-500 nm, and filtering performance is not flat across that range: a lens can filter nearly all light at the short, high-energy end near 400 nm while passing most of the light just 50 nm further along. Reporting one number without the band lets a lens sound like it blocks “most” blue light when it may only block a narrow slice of it. Our own clear lens shows the effect directly, measured in the same COLTS Laboratories report: 99.99% filtered at 400 nm, 95.1% at 410 nm, 63.0% at 420 nm, and 33.1% at 450 nm. All four are true statements about the same lens, and all four describe very different amounts of light reaching the eye. Any blue-light percentage that omits the wavelength it was measured at should be treated as incomplete.

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What our measured lenses actually filter

Below is what our lenses filter by band, as measured. The clear-lens and yellow-evening-lens figures come from COLTS Laboratories report O-SPG111015; the orange and red figures come from 2026 testing by our lens manufacturer’s optical laboratory. The ZENOX clear lens is a useful contrast: at roughly 52% average across the blue band, it shows that a clear, comfortable, all-day lens cannot also filter the entire band the way a heavily tinted lens can. Orange and red lenses filter the most across 380-500 nm of anything we measure, but neither is suitable for driving, since both cut too much visible light and shift color perception to be used safely behind the wheel.

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Higher block percentages have not shown proportionally higher benefit

Independent research does not support the idea that more filtering means proportionally more measurable benefit. A 2017 study in PLOS ONE (Leung, Li & Kee) found that commercially available blue-light-filtering lenses reduced the calculated blue-light hazard by roughly 10-24%, a modest range next to marketing language implying near-total filtering. On sleep specifically, a November 2025 meta-analysis in Frontiers in Neurology combining three randomized controlled crossover trials (n=49, actigraphy-measured) found sleep onset latency, total sleep time, sleep efficiency, and wake-after-sleep-onset were all statistically non-significant; the authors’ conclusion was that blue-blocking glasses may provide small improvements, but current RCT evidence does not support significant effects. A separate January 2026 review in Therapeutic Advances in Ophthalmology (Khorrami-Nejad, Naroo, Oklla, Narooie-Noori) reported that blue-light-filtering spectacle lenses showed minimal or no significant impact on contrast sensitivity, color discrimination, or task performance compared with standard lenses, and described the evidence on eye strain and circadian and sleep outcomes as debated. None of this means filtering does nothing; it means the research has not established that a bigger blocking percentage translates into a bigger outcome.

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How to choose a lens without chasing a percentage

Since no percentage is officially required and higher numbers have not shown proportionally larger measured benefit, the more useful question is which band and transmission level fit the use case. For daytime and screen work, a near-clear lens with high visible transmission, like our clear lens at 91.6%, avoids darkening the world while still filtering strongly at the shorter end of the band (99.99% at 400 nm). For evening use where the goal is heavier coverage across the whole 400-500 nm band, including the 460-480 nm melatonin-sensitive range, a yellow-tinted lens filters more broadly at the cost of visible transmission (about 65%). Whichever lens is chosen, the current evidence for symptom-level outcomes such as sleep or eye strain is limited and contested rather than settled, so a blue-light lens should be treated as one variable among several (screen brightness, room lighting, break frequency), not a stand-alone fix. Anyone comparing lenses should ask for the wavelength band behind any quoted percentage before treating it as meaningful.

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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. Our rule for what may appear on this page at all is on how we choose what to publish.

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Related questions

• Clear vs yellow (amber) blue light lenses: what is the difference?
• What do orange lenses do?
• What do red lenses do?
• Do clear blue light lenses actually work?
• Why do some blue light glasses have a yellow tint?
• What does an anti-reflective coating do?

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