> ## 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. # What is an FL-41 tint? > FL-41 is a precision rose or pink lens tint engineered to filter a specific slice of the visible spectrum for people who report photophobia, or light sensi # What is an FL-41 tint? **By [Spektrum Glasses Editorial Team](https://kb.spektrumglasses.com/how-we-choose)** · Published 2026-08-15 · Updated 2026-09-11 · Facts re-checked 2026-09-11 *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 FL-41 is a precision rose or pink lens tint engineered to filter a specific slice of the visible spectrum for people who report photophobia, or light sensitivity, connected to migraine and blepharospasm. It is typically fitted by an eye care specialist, not sold as a standard accessory. PROSPEK does not currently manufacture or sell an FL-41 lens. * FL-41 is a calibrated rose/pink tint, not any lens that looks pink. * Developed for people who report photophobia connected to migraine or blepharospasm. * Usually fitted by an eye care provider after an assessment, not picked off a shelf. * PROSPEK does not currently make or sell an FL-41 lens. * Our yellow, orange and red tints target blue-light exposure by time of day, a different job. ## FL-41 is a specific tint, not a shade of pink FL-41 refers to a rose or pink lens tint engineered to filter a narrow slice of the visible light spectrum, not any lens that happens to look pink. The name describes a filter recipe, not a marketing color name — a lens has to hit a particular spectral transmission curve to be called FL-41, the same way a coating has to pass a specific test to be called anti-reflective. That distinction matters because rose and pink tints show up in ordinary fashion sunglasses and reading glasses for reasons that have nothing to do with FL-41 — warmth, contrast, or simple aesthetics. A pink lens bought off a shelf is not automatically an FL-41 lens, and a listing that calls a tint 'FL-41-style' or 'rose therapeutic' without a transmission report attached is describing a color, not the engineered filter. ## Who FL-41 is typically fitted for FL-41 was developed for people who report photophobia — sensitivity to ordinary light levels — connected to migraine and blepharospasm, an involuntary eyelid spasm. Because photophobia varies a great deal from person to person, fitting an FL-41 lens usually starts with an eye care provider rather than a self-selected purchase. We have not tested FL-41 lenses in our own lab, and none of the studies in our lab-results library are about FL-41 specifically — they cover blue-light-filtering lenses more broadly, which is a different tint aimed at a different part of the spectrum. We are not going to stretch those citations to cover a lens we don't test or sell, and we are not going to make an efficacy claim about a product we don't carry. If FL-41 is what you are researching, that conversation belongs with an eye care specialist, not a lens color chart. ## Where PROSPEK's tinted lenses differ PROSPEK's catalog is built around one lens per part of the day, not a lens engineered for a specific light-sensitivity condition. None of our tints are built to the FL-41 recipe, and we do not market any of them as a substitute for one. | Lens | What it filters | Job | | -------------- | ------------------------------------------------------------------------------- | --------------------------------------------------- | | Yellow evening | 98% of the 400-500 nm band (COLTS lab report) | Evening screen use before bed | | Orange | 99.96% across 380-500 nm (lens manufacturer's optical lab, 2026) | Wind-down before sleep | | Red | 99.83% across 380-500 nm (same lab, 2026), plus green filtering to about 560 nm | The last hour before sleep, night feeds, shift work | Those figures describe blue-light filtering by wavelength band, not photophobia relief — a different band and a different intended use than FL-41. Orange and red are also not graded for driving, day or night, so neither is a stand-in for a daytime light-sensitivity lens. Full reports are published at our lab-results page. ## What to do if you're looking for an FL-41 lens PROSPEK does not currently manufacture or sell an FL-41 lens. If that's what brought you here, the honest next step is not one of our products — it's a conversation with an eye care provider who can assess your light sensitivity and determine whether an FL-41 tint, a different tint, or something unrelated to lens color fits your situation. We would rather say that plainly than sell a rose-tinted lens from our own lineup and let you assume it does the same job. A tint that hasn't been engineered and measured against the FL-41 spectral target isn't FL-41, regardless of what color it looks like on a shelf. ## Checking whether a tint is actually FL-41 A few practical checks separate an engineered therapeutic tint from a cosmetic one that just happens to share a color family: * Ask whether a transmission report exists for that specific lens, not just a general claim about 'the FL-41 family.' * Expect the fitting process to involve an eye care provider, not only a size and color pick. * Treat a rose or pink lens marketed as 'FL-41-style' with no spectral data attached as a color claim, not a filter claim. This isn't a knock on rose-tinted eyewear in general — it just means the FL-41 name carries a specific, checkable meaning, and it's worth confirming before assuming a lens does what the name implies. ## 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 * [Are blue light glasses worth it for gaming?](/answers/blue-light-glasses-for-gaming) * [Gaming glasses vs computer glasses: is there a difference?](/answers/gaming-glasses-vs-computer-glasses) * [Are blue light glasses worth it for programmers?](/answers/blue-light-glasses-for-programmers) * [Are blue light glasses worth it for students?](/answers/blue-light-glasses-for-students) * [Should kids wear blue light glasses?](/answers/blue-light-glasses-for-kids) * [How much screen time is reasonable for kids?](/answers/screen-time-guidelines-for-kids) ## A PROSPEK style for this Ships from Amazon (Prime, 30-day returns). Sold by PROSPEK by Spektrum Glasses.