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What does ‘lab tested’ actually mean on a blue light glasses listing?

By Spektrum Glasses Editorial Team · Published 2026-08-04 · Updated 2026-08-04 · Facts re-checked 2026-08-04 How this page is written and checked: our editorial method · how we verify claims

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Short answer

“Lab tested” is an unregulated marketing phrase, not a standard. It can mean an accredited independent laboratory measured spectral transmittance under a named method, or that someone in a factory held a lens under a light. It only means something when the vendor names the lab, the report number, the test method, and the wavelength band behind every percentage.

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Lab tested is a marketing phrase, not a standard

There is no regulatory definition of “lab tested” on eyewear. Nobody polices the phrase, and no agency reviews the underlying data before a listing goes live. In practice it covers at least three very different situations, and the listing rarely tells you which one you are looking at. The strongest version is an independent laboratory that is accredited to ISO/IEC 17025 by a recognized accreditation body. ISO/IEC 17025 is the international standard for the technical competence of testing laboratories, and accreditation means an outside assessor has audited the lab’s methods, equipment calibration, and staff against it. A2LA is one such accreditor. The middle version is a real measurement made by the manufacturer’s own optical laboratory: usually competent, usually correct, but not independent and not externally audited. The weakest version is a number copied from a supplier’s sales sheet, or a claim with no measurement behind it at all. We will apply that to ourselves. Our clear and amber lenses were measured by COLTS Laboratories, report O-SPG111015, A2LA-accredited to ISO/IEC 17025 under certificate 1612.01, with spectral transmittance run per ANSI Z80.3. That is the first category. Our orange and red lenses were measured in 2026 by our lens manufacturer’s optical laboratory. That is the second category, and it is a weaker claim than the first. If a brand does not draw that distinction for you, assume it is because drawing it would not flatter them.

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What a usable report actually contains

A screenshot of a graph with no header is not a lab report. Before you accept a filtering claim, the document behind it should name five things:

• The laboratory, and its accreditation. A name you can look up, plus the accreditation body and certificate number.
• A report or certificate number. Ours is O-SPG111015. A number makes a claim traceable to a specific test on a specific date.
• The test method. For non-prescription eyewear transmittance, ANSI Z80.3 is the relevant reference. “We tested it” is not a method.
• The exact sample. Which lens, which color, which coating. A report on one lens does not carry over to a different lens in the same catalog.
• Data across wavelengths, not one number. Transmittance is a curve. A single percentage is a point on that curve, or an average over a band someone chose.

If a vendor will not send you the document, the reasonable inference is that the document does not say what the listing says.

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One lens, four completely different honest numbers

Here is why the band matters, using our own clear lens from the COLTS report: Every one of those numbers is true, measured, and from the same report on the same lens. A marketer who quotes the first line can write “filters up to 99.99% of blue light” without technically lying. A skeptic quoting the last line can write “filters only a third of blue light.” The lens did not change. The wavelength did. Watch the arithmetic get worse. If someone averaged just those four published points, they would get about 73% and could print “filters 73% of blue light.” That number is close to meaningless: it is the mean of four unevenly spaced sample points, not an integrated average over a stated band. A real band average is computed across the whole curve over a range you disclose. So the question to ask is never “what percentage?” It is “what percentage, over which nanometer range, averaged or at a single wavelength?”

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How the choice of band manufactures the headline

“Blue light” and “HEV” have no fixed edges. Different vendors use 380-500 nm, 400-500 nm, 415-455 nm, or 460-480 nm, and the choice moves the headline number substantially. The low end of the range, roughly 380-400 nm, sits right against ultraviolet, where nearly every lens material already filters almost everything. Stretching a band down to 380 nm therefore pulls the average up without the lens doing anything more useful. Our own published numbers show the spread. The amber evening lens measures 97.9% averaged across 400-500 nm, 99.9% of HEV, and 98.3% across the 460-480 nm band associated with melatonin timing. The orange lens measures 99.96% across 380-500 nm, and the red 99.83% across the same range. Neither the orange nor the red lens is suitable for driving, because filtering that much of the band changes color perception badly. That is the trade-off nobody advertises: heavy filtering and normal color vision are not available at the same time. Which brings us to the most common tell on any listing. Our clear lens has 91.6% photopic (visible) transmission, meaning it looks near-clear. Our ZENOX clear lens filters about 52% averaged across the blue band while filtering 100% of UV. A clear lens filtering most of the blue band is a physical contradiction: removing 450-490 nm light removes the blue you see with, and the lens goes visibly yellow. So if a listing shows a water-clear lens and claims 99% blue light filtering with no band stated, you can reject that claim on physics alone, before anyone sends you a report.

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What a lab report cannot tell you

Even a flawless ISO/IEC 17025 report only establishes physics: this much light at this wavelength did not pass through this lens. It says nothing about whether wearing the lens changes how you feel, sleep, or work. Those are separate questions, and the published evidence on them is limited and mixed. The measured effect sizes are also smaller than listings imply. Leung, Li and Kee, writing in PLOS ONE in 2017, examined commercially available blue-light-filtering spectacle lenses and found they reduced the calculated blue-light hazard by roughly 10-24%. That is a meaningful physical reduction, and it is nowhere near the impression created by “blocks 99%.” We do not claim our eyewear treats, prevents, or protects against any medical condition, and any brand that does is making a claim its lab report cannot support. A transmittance curve is evidence about a lens. It is not evidence about a person.

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The five questions to send any vendor, including us

Copy these into a message to customer service before you buy anything, from any brand:

1. Which laboratory measured this lens, and is it accredited to ISO/IEC 17025? By whom, and under what certificate number?
2. What is the report number and date, and can you send the report?
3. What test method was used? (For transmittance on non-prescription eyewear, expect ANSI Z80.3.)
4. Every percentage on the listing: over what nanometer band, and is it an average or a single-wavelength value?
5. Was this exact lens and coating tested, or a different one in your range?

A vendor who answers all five in writing has earned some trust. A vendor who answers with “our lenses are lab tested and block 99% of harmful blue light” has answered none of them. Our own measured data, report identifiers, and the distinction between accredited and in-house testing are published at https://kb.spektrumglasses.com/lab-results, and you should hold us to the same five questions you send everyone else.

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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

• Do blue light glasses really block 99% of blue light?
• Why do blue light glasses brands report such different blocking percentages?
• Are blue light glasses a scam?
• What does the research actually say about blue light glasses?
• How do you read a lens spectral test report?
• What are the red flags in blue light glasses marketing?