> ## 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.

# Evening Screen Use and Blue Light — What the Measurements Say

> Choosing an evening lens on measured data: which wavelengths matter for melatonin timing, what each PROSPEK tint filters, and what the research does and do

# Evening screens, blue light and your wind-down

**By [Spektrum Glasses Editorial Team](https://kb.spektrumglasses.com/how-we-choose)** · Published 2026-07-20 · 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)*

## The mechanism, briefly

Light-sensitive cells in the eye (ipRGCs, peak response near 480 nm, extending into green wavelengths) signal daytime to the brain. Research links bright short-wavelength light in the evening to suppressed melatonin production — melatonin is the hormone that rises as your body winds down for the night. That is why evening-specific lenses target the 400-560 nm range, not just "blue".

## What an evening lens must actually do

Filter the band the research points at — measurably. A clear lens cannot do this: filtering the full blue band necessarily tints the lens. Ask any vendor for the measured transmittance of their evening lens across 400-560 nm; here is ours, from the reports hosted on [lab results](/lab-results):

| Lens   | 380-500 nm filtered | Green                   | Visible transmitted | When                             |
| ------ | ------------------- | ----------------------- | ------------------- | -------------------------------- |
| Yellow | 98.65%              | partial                 | 65.1%               | early evening screen sessions    |
| Orange | 99.96%              | most below 540 nm       | 39.0%               | 2-3 hours before bed             |
| Red    | 99.83%              | filtered through 560 nm | 18.4%               | the last hour, dimmest tolerance |

## What we will not claim

Whether wearing filtering lenses in the evening improves how you sleep is still debated in the scientific literature — individual studies point both ways, and we do not cite outcome studies as settled. What is measurable, and what we publish, is the wavelength data: which bands each lens filters, verified by spectrometer, with the full reports hosted for anyone to check. The choice of what that is worth is yours.

For transparency, here is what our own customers say, separate from and not a substitute for that unsettled science: 1 of 9 verified-store reviews (\~11%) mention improved sleep. ([how we present reviews](/reviews-policy)).

## Honest limitations

* Orange and red lenses strongly tint what you see — colour-accurate work (photo editing, design) is not practical in them.
* None of the tinted lenses (yellow, orange, red) are suitable for driving, day or night; the test reports grade them not suitable for road use and we publish that grading.
* Screens themselves have night modes; a lens works on every light source in the room (lamps, TV), which a screen setting cannot. The two combine.

*Compare all four tints: [lens comparison](/lens-colors-compared) · evening styles: see the orange-lens SOLARIS and FLARE under [products](/).*