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Speaking of eye health, I wonder what effects programs like f.lux and their newer built-in alternatives have. Despite a bit of trepidation when first giving it

Speaking of eye health, I wonder what effects programs like f.lux and their newer built-in alternatives have. Despite a bit of trepidation when first giving it a try, after a while it feels very natural. Since ebook readers have become more commonplace in the last 20 years, I also have to wonder what effects that might have on us. Even on days when I avoid using my computer, I still spend a good couple of hours reading ebooks on a tablet. There have also been tons of advancements in technology. I don't think high-DPI displays were commonly available, but the technology is increasingly commonplace, especially on mobile devices.

gsich 9y ago
Don't know it is has any effect health-wise, but it is still very comfortable.
tzs 9y ago
Note that many tablets support things equivalent to f.lux. Apple tablets do, I believe. So does Surface Pro and probably many other Windows based tablets [1]. A lot of people claim that the Kindle Paperwhite does not need it because the display is not back lit. (The lights are on the edge, and there is a transparent light guide in front of the eInk display that directs this light so that it shines on the eInk from the front and reflects off it to you). This seems like complete bullshit to me, because I can not see any way that the intrinsically photosensitive retinal ganglion cells in your eye could possibly tell if photons come from a front lit display or a back lit display. All they should care about is the wavelength and the intensity. That's not to say that the claims that the Paperwhite doesn't need a reduced blue light mode aren't true--I'm just saying that if they are true it isn't because it is not back lit. It would be because they are using a light source with less blue, or the eInk display absorbs blue so that it does not reflect much blue from the light source. Speaking of reducing blue light at night...I've wondered if what is important is the absolute amount of blue light or the relative amount compared to daytime levels. The intrinsically photosensitive retinal ganglion cells signal the suprachiasmatic nucleus (SCN) in the brain with the amount of blue light they are receiving. The SCN responds to changes in that to control circadian rhythms. If the SCN is just watching the levels and looking for them to cross certain fixed thresholds, then at night we'd need to make sure we drop blue light below certain absolute levels. If, on the other hand, the SCN is looking for relative changes, such as blue light dropping to below some percentage of the peak over the last 12 hours, or over some kind of average over the last several hours, then instead of working to eliminate blue light at night it should be possible to achieve the same effects by increasing blue light during the day. So instead of trying to find software to reduce the blue light on every screen in my house (an increasingly hard thing to do as more and more things have screens), I should be able to install lights that have very high blue levels and have them on during the day, to push the blue light threshold high enough that when I turn those lights off I am below it even though my TV and other screens do not have low blue light modes. [1] Windows in general supports it, but I believe it requires some support from the GPU, so whether or not it works on a particular tablet depends on the hardware.
- walterbell 9y ago
  This page links to research on blue light effects, https://glarminy.com/2016/04/11/are-your-eyes-sensitive-to-light-or-blue-light/ https://glarminy.com/2016/04/11/are-your-eyes-sensitive-to-l...

gsich 9y ago

Don't know it is has any effect health-wise, but it is still very comfortable.

tzs 9y ago

Note that many tablets support things equivalent to f.lux. Apple tablets do, I believe. So does Surface Pro and probably many other Windows based tablets [1]. A lot of people claim that the Kindle Paperwhite does not need it because the display is not back lit. (The lights are on the edge, and there is a transparent light guide in front of the eInk display that directs this light so that it shines on the eInk from the front and reflects off it to you). This seems like complete bullshit to me, because I can not see any way that the intrinsically photosensitive retinal ganglion cells in your eye could possibly tell if photons come from a front lit display or a back lit display. All they should care about is the wavelength and the intensity. That's not to say that the claims that the Paperwhite doesn't need a reduced blue light mode aren't true--I'm just saying that if they are true it isn't because it is not back lit. It would be because they are using a light source with less blue, or the eInk display absorbs blue so that it does not reflect much blue from the light source. Speaking of reducing blue light at night...I've wondered if what is important is the absolute amount of blue light or the relative amount compared to daytime levels. The intrinsically photosensitive retinal ganglion cells signal the suprachiasmatic nucleus (SCN) in the brain with the amount of blue light they are receiving. The SCN responds to changes in that to control circadian rhythms. If the SCN is just watching the levels and looking for them to cross certain fixed thresholds, then at night we'd need to make sure we drop blue light below certain absolute levels. If, on the other hand, the SCN is looking for relative changes, such as blue light dropping to below some percentage of the peak over the last 12 hours, or over some kind of average over the last several hours, then instead of working to eliminate blue light at night it should be possible to achieve the same effects by increasing blue light during the day. So instead of trying to find software to reduce the blue light on every screen in my house (an increasingly hard thing to do as more and more things have screens), I should be able to install lights that have very high blue levels and have them on during the day, to push the blue light threshold high enough that when I turn those lights off I am below it even though my TV and other screens do not have low blue light modes. [1] Windows in general supports it, but I believe it requires some support from the GPU, so whether or not it works on a particular tablet depends on the hardware.

walterbell 9y ago
This page links to research on blue light effects, https://glarminy.com/2016/04/11/are-your-eyes-sensitive-to-light-or-blue-light/ https://glarminy.com/2016/04/11/are-your-eyes-sensitive-to-l...