Evening use of light-emitting eReaders negatively affects sleep (2014)(pnas.org)
pnas.org
Evening use of light-emitting eReaders negatively affects sleep (2014)
https://www.pnas.org/doi/10.1073/pnas.1418490112
56 comments
We should change the title to reflect this. I came in here expecting to read about the dangers of e-ink displays at night and that is not what the study is about
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Shade throwing would be justified in my opinion. "E-reader" isn't normally used to describe tablets. The light profile of a dynamic LED screen is probably very different from the ambient steady backlight on a Kindle.
Or even a Kobo (at least my old one) where the light is under the frame at the top, and projects down onto the screen so you're getting reflected light similar to an external source.
Kindles have a backlight? Then I expect it to be LED as well. I'm not sure then you can be so dismissive of a back-lit Kindle and its effect on evening reading.
They have a frontlight rather than a backlight. And there's quite a bit of evidence that colour temperature and brightness both have a big effect. But I broadly agree that it will still have an effect. I use my kindle without the backlight and with a warm coloured lamp.
Technically it’s a front-light, shining on the front of the screen from the side. But the nature of the eInk is such that you don’t have to use the built in light, you could just turn in your normal lamp.
Also,
"Third, in the present study, the LE-eBook was set to maximum brightness throughout the 4-h reading session"
"Third, in the present study, the LE-eBook was set to maximum brightness throughout the 4-h reading session"
Christ. Can you imagine reading on a max brightness iPad in a dark room? I put my ereader (an actual ereader with an e-ink screen, not “ereader as in electronic thing you read on with a laptop screen” as in the article) on the lowest brightness setting with natural orange-tinted light. And I still feel like it’s pretty bright!
Same, and I can say at least for me, it unquestionably helps sleep, because I start to feel tired and go to sleep about 10 minutes after I start reading, whereas if I were to stay engaged with my desktop, I could easily stay up hours longer. I go to sleep earlier, and fall asleep faster, since adding my Kobo Forma to my evening routine.
Same, I often find my iphone in a dark room on lowest brightness to be too bright if the page doesn't support dark mode.
There's an accessibility setting which you can use to further darken the screen. I have it set to toggle on a triple click of the home button.
Reduce Whitepoint? Seems to have that effect but not sure if that's the one you are thinking.
I think they're talking about the accesibility filters: https://9to5mac.com/2016/03/18/how-to-reduce-iphone-screen-b...
I used to use it daily just before going to sleep, but then found the app I read with has a white text on black background that I prefer. Using both at the same time makes it too dark for my eyes, which is a good problem to have.
I used to use it daily just before going to sleep, but then found the app I read with has a white text on black background that I prefer. Using both at the same time makes it too dark for my eyes, which is a good problem to have.
Also, the control group is not someone reading a book with a lamp, but someone reading a book in a dark room without a lamp. So really it boils down to 'light' or 'no light'.
So sleeping? Not sure how you read in complete dark…
The control group was allowed to use reading lamps and adjust lights and seating position to their liking.
Can you point me where that is described? All I find is "(ii) reading a printed book in the same very dim room light for ∼4 h before bedtime for five consecutive evenings", highlight mine.
"very dim room"...
I think at the time, no Kindles had back-lights. That's since changed so I'd be curious which side they'd be on in the study then.
I hate to nitpick, but Kindles still don't really have "backlights"; they're called "frontlights". Basically it's a "light-conducting" layer on top of the screen that's illuminated by LEDs at the top, bottom, or both. It's hard to describe, but the effect is very different from backlit tablets, and much more gentle. It's like this for all e-Readers AFAIK.
It would be interesting to see a study especially since the tech is so different.
It would be interesting to see a study especially since the tech is so different.
That is some weird miscommunication. Did someone in Texas get afraid of calling out Apple? Why else would people choose to call an iPad (or tablet computer for that matter) an LE-eReader?
I'm too lazy to find it now but I read research that showed it did not have the same impact (lacking the high amount of blue light) which is why I read on a kindle paperwhite.
I love my note-taking and drawing on my iPad, but have found significant benefits from switching over to an old 3rd gen kindle for any kind of extended reading.
Came here to add another voice to the discourse that an iPad is most definitely not a "light-emitting eReader" in popular vernacular. That term calls to mind recent e-ink devices with frontlights, which are often used in place of LCD-devices to allow for some time away from harsher backlit screens before bed.
Burying that lede several sections deep feels almost purposely misleading, either that or just incompetent in my opinion.
Burying that lede several sections deep feels almost purposely misleading, either that or just incompetent in my opinion.
From TFA:
> The LE-eBook was set to the maximum brightness setting.
Others on this thread have pointed out that it's an iPad.
For years now, this has seemed like common sense to me. Of course you don't want to blast a tablet or laptop screen at 100% brightness when you're trying to get your brain to fall asleep.
I use a Kobo e-reader with its brightness set to 1%. I can't imagine that exposes my eyes to light amplitudes that would exceed that of a lamp. In a dark room I don't have any problem reading the words, and I don't think I've had any sleep problems.
> The LE-eBook was set to the maximum brightness setting.
Others on this thread have pointed out that it's an iPad.
For years now, this has seemed like common sense to me. Of course you don't want to blast a tablet or laptop screen at 100% brightness when you're trying to get your brain to fall asleep.
I use a Kobo e-reader with its brightness set to 1%. I can't imagine that exposes my eyes to light amplitudes that would exceed that of a lamp. In a dark room I don't have any problem reading the words, and I don't think I've had any sleep problems.
My anecdotal two-cents:
I will stay up nearly indefinitely in bed if I read my phone or iPad. Read the same material on my Kindle Paperwhite and it can be difficult to stay awake more than a few minutes.
I don’t know if it has anything to do with the difference in screen types, as my Kindle does have a backlight but it is so night and day for me, I am predisposed to believe anything that states there is a mechanism for my experience.
I will stay up nearly indefinitely in bed if I read my phone or iPad. Read the same material on my Kindle Paperwhite and it can be difficult to stay awake more than a few minutes.
I don’t know if it has anything to do with the difference in screen types, as my Kindle does have a backlight but it is so night and day for me, I am predisposed to believe anything that states there is a mechanism for my experience.
Leds in a phone or tablet screen are directing the light to your eyes, where with a backlit screen, that light is diffused over the area of the screen. So the intensity of direct light from "LE-eReaders" is probably way higher than that of a backlit screen.
Also, it might have to see with the level of blue light that is emitted by those devices. Light in backlit screens is somewhat filtered and might not contain as much blue.
Also, it might have to see with the level of blue light that is emitted by those devices. Light in backlit screens is somewhat filtered and might not contain as much blue.
> Also, it might have to see with the level of blue light that is emitted by those devices
In my experience backlit screens contain a lot of blue. I have been able remove the waking effect of my screen entirely using a heavy red filter provided by f.lux. But with the default settings, and even Apple's night shift implementation it's very blue. It is slightly less bad on newer devices that support "TrueTone".
In my experience backlit screens contain a lot of blue. I have been able remove the waking effect of my screen entirely using a heavy red filter provided by f.lux. But with the default settings, and even Apple's night shift implementation it's very blue. It is slightly less bad on newer devices that support "TrueTone".
Elsewhere I would agree with you but this study was using:
"The randomized, crossover protocol design consisted of two conditions: (i) reading an LE-eBook (iPad; Apple Inc., Cupertino, CA) in otherwise very dim room light for ∼4 h before bedtime for five consecutive evenings, and (ii) reading printed books in the same very dim room light for ∼4 h before bedtime for five consecutive evenings"
In other words, they compared using a tablet to reading a book. Unsurprisingly, they found that using the tablet negatively affects sleep.
"The randomized, crossover protocol design consisted of two conditions: (i) reading an LE-eBook (iPad; Apple Inc., Cupertino, CA) in otherwise very dim room light for ∼4 h before bedtime for five consecutive evenings, and (ii) reading printed books in the same very dim room light for ∼4 h before bedtime for five consecutive evenings"
In other words, they compared using a tablet to reading a book. Unsurprisingly, they found that using the tablet negatively affects sleep.
During LE-eBook reading sessions, the light-emitting device was set to maximum brightness and placed in a stand that held it at a fixed angle. This stand was placed on a table directly in front of the individual at a 30- to 45-cm distance from their eyes. Participants were allowed to turn pages on the LE-eBook, but were asked not to hold it while reading or make any adjustments to the settings. During the printed book reading sessions, participants were allowed to hold the book at any desired distance from their eyes.
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Note that maximum brightness on an iPad is intended for reading in direct sunlight.
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Note that maximum brightness on an iPad is intended for reading in direct sunlight.
Try setting the screen to greyscale. For me personally switching to greyscale immediateky makes the device less rewarding to simply look at. When it is colour I am mesmerised by the beautiful colours and end up reading the text without actually taking anything in.
> I will stay up nearly indefinitely in bed if I read my phone or iPad. Read the same material on my Kindle Paperwhite and it can be difficult to stay awake more than a few minutes.
I've noticed the same thing! Glad to see I'm not nuts...
I've noticed the same thing! Glad to see I'm not nuts...
I can add an anectode at the other end of the sleep cycle:
I used to have a hard time waking up, even with alarms.
Now I just reach for my phone while I'm still half asleep.
The bright screen wakes me up every time.
I used to have a hard time waking up, even with alarms.
Now I just reach for my phone while I'm still half asleep.
The bright screen wakes me up every time.
Classifying an iPad as an eReader is a bit misleading IMHO. I would have never made the connection if it wasn't mentioned in the article.
The intensity of light needed on an iPad to read comfortably is much higher then a backlit eInk reader e.g. a Kindle Paperwhite. Personally it doesn't affect me very much on such devices, but it would be interesting to see if there is a noticeable difference.
The intensity of light needed on an iPad to read comfortably is much higher then a backlit eInk reader e.g. a Kindle Paperwhite. Personally it doesn't affect me very much on such devices, but it would be interesting to see if there is a noticeable difference.
Because this article is about ipad vs book, here is my personal experience with eInk readers (no Light Sony PRS-350, light layer Kobo Aura HD) and personal setup of red on black on amoled on minimal lightness Samsung Note 10:
Personally I define something to not affect my sleep, when I got trouble staying awake after one or two chapters on a workday.
PRS-350 (no light eink): Like a real book, it mostly depends on the light setup of the room. With a warm, indirect and just enough to not have trouble reading dim light, I easily get sleepy and in trouble to stay awake long enough to poweroff device and lamp. I did fall asleep with device in hand often enough, even on a plane once.
Aura HD (light layer eink, one of the first gens): Had to stop myself reading often after looking at the clock or how many chapters I read. Just one more chapter, was a real problem with it. But I didn't had any trouble falling asleep after putting it away.
Note10 kobo reader (amoled, red text on black, "background light off mode"): Need more time than PRS-350 or real book, but I definitely got trouble keeping my eyes open after a while. Sometimes I switch it off and already fall asleep before I get the chance to put the phone out of my hand.
Note10 anime reader app/websites/etc: Even without videos or other animated/interactive media, I stay awake indefinitely. If I fall into that trap, it is common for me to stay awake to at least 2am, sometimes up to 5am.
Personally I define something to not affect my sleep, when I got trouble staying awake after one or two chapters on a workday.
PRS-350 (no light eink): Like a real book, it mostly depends on the light setup of the room. With a warm, indirect and just enough to not have trouble reading dim light, I easily get sleepy and in trouble to stay awake long enough to poweroff device and lamp. I did fall asleep with device in hand often enough, even on a plane once.
Aura HD (light layer eink, one of the first gens): Had to stop myself reading often after looking at the clock or how many chapters I read. Just one more chapter, was a real problem with it. But I didn't had any trouble falling asleep after putting it away.
Note10 kobo reader (amoled, red text on black, "background light off mode"): Need more time than PRS-350 or real book, but I definitely got trouble keeping my eyes open after a while. Sometimes I switch it off and already fall asleep before I get the chance to put the phone out of my hand.
Note10 anime reader app/websites/etc: Even without videos or other animated/interactive media, I stay awake indefinitely. If I fall into that trap, it is common for me to stay awake to at least 2am, sometimes up to 5am.
They speculate that the harmful component of e-readers is the blue-shifted illumination. I’d be curious if newer e-readers with temperature controllable backlights set to “warm” mitigates some of this sleep harm
Also the kindles use significantly less light that aren’t emitted directly into your eyes (rather up/down on the screen). That’s what I thought this study was at first. I have a non illuminated kindle for years and I’m wondering the same thing for when I inevitably have to replace it. A built in warm & dim light is convenient especially if it doesn’t adversely affect things. If not back to candles for me!
iPad on maximum brightness is what they were using. They sure buried it!
That would be close to painful and certainly very unpleasant in a dim room at night.. WTH were the study authors thinking?
The iPad won't even do that without the user manually setting it up to do that, and almost no one is going to find it comfortable.
It seems more like they were trying to set the conditions to get the result they desired. They could have shined an LED flashlight into the user's eyes and gotten the same result.
That would be close to painful and certainly very unpleasant in a dim room at night.. WTH were the study authors thinking?
The iPad won't even do that without the user manually setting it up to do that, and almost no one is going to find it comfortable.
It seems more like they were trying to set the conditions to get the result they desired. They could have shined an LED flashlight into the user's eyes and gotten the same result.
> WTH were the study authors thinking?
They were thinking that they wanted a publishable result.
Unfortunately, little to no difference on sleep between dim e-reader at night vs book and dim light wouldn't get published even though would be really useful to know.
They were thinking that they wanted a publishable result.
Unfortunately, little to no difference on sleep between dim e-reader at night vs book and dim light wouldn't get published even though would be really useful to know.
It would seem to me that "there is no difference with appropriate light intensity settings" would be a much more publishable result? That max. brightness affects sleep is an unsurprising "common sense" result (although still worth doing research over just to verify), but I – and I think many people – genuinely don't know if there's an effect with low light settings (and/or colour temperature settings), and if there's an effect, how large that effect might be. In short: that seems a much more interesting study.
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?
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
The dark amber glass from swanwick have similar optical density curve: 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...
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.
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
The dark amber glass from swanwick have similar optical density curve: 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...
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.
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.
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.
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.
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/10.1177/074873041558541...
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/10.1177/074873041558541...
> 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)
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)
iPad on full brightness is not the same thing as an ereader. This study has some serious problems. I'm surprised there hasn't been a recent study with the current generation of ereaders (Kindle Oasis in particular) that measures melatonin level. Ideally, I'd like to see light levels calibrated to the same level between an eink device vs LED tablet vs an actual book vs a no bedtime reading condition.
In my experience the iPad & iPhone cannot approach the dim levels side-lit eInk readers can. The minimum brightness on iPad/iPhone is about 50% of max on my Kindle Oasis, so it might be hard to do a realistic study comparing the two, one or both of the devices would end up far out of the normal range users would select in order to match brightness.
If I'm reading in a darkened room on my kindle I have the brightness on the kindle set lower than it's possible to do so on an iPhone or iPad.
I think this is common, which shows how crazy it is the study had an iPad on maximum brightness and had the user read for hours in that configuration. I'd have red eyes and a splitting headache by the end of that which would of course have negatively effected my sleep.
If I'm reading in a darkened room on my kindle I have the brightness on the kindle set lower than it's possible to do so on an iPhone or iPad.
I think this is common, which shows how crazy it is the study had an iPad on maximum brightness and had the user read for hours in that configuration. I'd have red eyes and a splitting headache by the end of that which would of course have negatively effected my sleep.
Pro-tip: use the kindle paperwhite on 3-6 brithgness and fall asleep easily!
It works wonders for me, honestly, I find I fall asleep easier with reading on a not-bright e-ink reader. I also have a kobo reader which is more yellow in its hue, but also a tad brighter. That one also works well for me, I usually put the reader down in 10 minutes to sleep.
It works wonders for me, honestly, I find I fall asleep easier with reading on a not-bright e-ink reader. I also have a kobo reader which is more yellow in its hue, but also a tad brighter. That one also works well for me, I usually put the reader down in 10 minutes to sleep.
i don't use an ipad, i use a kindle pw2, but i feel like i can get to sleep quicker when reading than if i just plop down into bed and close my eyes.
Also, it was shockingly hard to find [for me], but the "light emitting ereader" referred to in the title was an Apple iPad. It's not specified what kind of iPad they used, and the study focussed solely on reading from the iPad vs reading from a printed book.
The authors do note (in Table S1, in the Supporting Information) that they don't consider a Kindle e-reader to be light-emitting.
(I'm not throwing shade (heh) at the study, just adding some pertinent information that I thought would be useful to know.)