3 ms·

I wonder if the type of illumination used for traditional book reading is relevant. I.e. would a bedside lamp with cold light provoke the same effects?

zachruss92 5y ago
From my understanding from what experts say any light will affect your sleep to some extent. The big issue with backlit screens are that the blue lights are projected directly into your eyes which compounds the effects as more photons hit your eyes.
- mekkkkkk 5y ago
  Is that true though? I was under the impression that two surfaces with the same perceived brightness would bombard your eyeballs with the same amount of photons. Regardless of whether or not the surface is emitting or reflecting light. On the other hand, maybe there is some filtering taking place when light is bounced off materials. I.e. blue wavelengths being absorbed by the paper.
- bXVsbGVy 5y ago
  This is both correct and wrong. Some lights affected more than others. A paper[1] funded by NIH published this year showed that ~12 log photons cm⁻² s⁻¹ on λ=460nm is enough to suppress melantonin production. I've discussed more on sibling thread. [1] https://journals.sagepub.com/doi/pdf/10.1177/0748730415585413 https://journals.sagepub.com/doi/pdf/10.1177/074873041558541...
nicoburns 5y ago
> would a bedside lamp with cold light provoke the same effects Almost certainly from my own anecdotal experience. There's a reason why bedroom lights tend to be warm (even though they're often now leds)
bXVsbGVy 5y ago
I spent the past weekend reading papers of blue light effects on melatonin suppression to decided if blue light blocking glass was supperted by science, and to know and to know the parameters I should consider. As today, the academic consensus is that Melatonin suppression, on the lower part of the spectrum, is regulated by melanopsin produced by the Intrinsically photosensitive retinal ganglion cells (ipRGCs) -- not blue rods. The photosensitivity of ipRGCs has λ_peek = ~460 (nm). They've done experiments with rats without cones and rods (but with ipRCS), and they displayed circadian cycles. Melatonin is also suppressed by lights on higher part of the spectrum, but haven't papers on it. I've decided in getting this safety glass: https://www.thorlabs.com/thorproduct.cfm?partnumber=LG3A https://www.thorlabs.com/thorproduct.cfm?partnumber=LG3A The dark amber glass from swanwick have similar optical density curve: https://www.swanwicksleep.com/ https://www.swanwicksleep.com/ I choose the safety glass instead of the swanwick glass because I have more confidence that a safety glass in conforming with the provided specification. Since I intend to use it home, I don't care about how it looks. It you want to customize your own glass, this company sells lens blank of filter that block a somewhat similar wavelength to the other products: https://laserprotection.com/product/laser-pointer-protective-lens-nite/ https://laserprotection.com/product/laser-pointer-protective... Zeiss also sells special lens for colorblind that blocks similar spectrum. But it is very hard to find information on how to get them online.

zachruss92 5y ago

From my understanding from what experts say any light will affect your sleep to some extent. The big issue with backlit screens are that the blue lights are projected directly into your eyes which compounds the effects as more photons hit your eyes.

mekkkkkk 5y ago
Is that true though? I was under the impression that two surfaces with the same perceived brightness would bombard your eyeballs with the same amount of photons. Regardless of whether or not the surface is emitting or reflecting light. On the other hand, maybe there is some filtering taking place when light is bounced off materials. I.e. blue wavelengths being absorbed by the paper.
bXVsbGVy 5y ago
This is both correct and wrong. Some lights affected more than others. A paper[1] funded by NIH published this year showed that ~12 log photons cm⁻² s⁻¹ on λ=460nm is enough to suppress melantonin production. I've discussed more on sibling thread. [1] https://journals.sagepub.com/doi/pdf/10.1177/0748730415585413 https://journals.sagepub.com/doi/pdf/10.1177/074873041558541...

nicoburns 5y ago

> would a bedside lamp with cold light provoke the same effects Almost certainly from my own anecdotal experience. There's a reason why bedroom lights tend to be warm (even though they're often now leds)

bXVsbGVy 5y ago

I spent the past weekend reading papers of blue light effects on melatonin suppression to decided if blue light blocking glass was supperted by science, and to know and to know the parameters I should consider. As today, the academic consensus is that Melatonin suppression, on the lower part of the spectrum, is regulated by melanopsin produced by the Intrinsically photosensitive retinal ganglion cells (ipRGCs) -- not blue rods. The photosensitivity of ipRGCs has λ_peek = ~460 (nm). They've done experiments with rats without cones and rods (but with ipRCS), and they displayed circadian cycles. Melatonin is also suppressed by lights on higher part of the spectrum, but haven't papers on it. I've decided in getting this safety glass: https://www.thorlabs.com/thorproduct.cfm?partnumber=LG3A https://www.thorlabs.com/thorproduct.cfm?partnumber=LG3A The dark amber glass from swanwick have similar optical density curve: https://www.swanwicksleep.com/ https://www.swanwicksleep.com/ I choose the safety glass instead of the swanwick glass because I have more confidence that a safety glass in conforming with the provided specification. Since I intend to use it home, I don't care about how it looks. It you want to customize your own glass, this company sells lens blank of filter that block a somewhat similar wavelength to the other products: https://laserprotection.com/product/laser-pointer-protective-lens-nite/ https://laserprotection.com/product/laser-pointer-protective... Zeiss also sells special lens for colorblind that blocks similar spectrum. But it is very hard to find information on how to get them online.