
Ask HN: Is FaceID harmfull for your eyes? - sfilargi
No, this is not a flamebait, hear me out.<p>Since I got the iPhone X I have noticed that when I would watch movies in bed at night, I would wake up with sore eyes that would eventually turn into headaches.<p>Searching the web I found a lot of people complaining about the PWM on the iPhone X, and I got convinced that it was the screen that was causing my eye strain, so stopped using the X.<p>Until I got the XR a few days ago. As usual I watched some Netflix while in bed before falling asleep and woke up with the all so familiar sore eyes. This meant that all this time it was not the OLED the one responsible for my headaches, but something else. The only other think that was new both in X and XR was the FaceID.<p>I started thinking how can it cause problems and came with the theory below. When I am at bed the room is really dark and so I set the brightness level on my iPhone to the lowest setting. My eye-pupils are fully dilated to adjust to the lack of light. My theory is that the FaceID illuminator doesn&#x27;t take into consideration the amount of light in the environment and uses the same intensity as if it was daylight.<p>To prove this I took a recording of my iPhone X in similar environment with an IR camera: https:&#x2F;&#x2F;youtu.be&#x2F;7ewR9wUjnsc<p>If this wasn&#x27;t IR but visible light it would be like the iPhone&#x27;s camera flash going on every 5 seconds right in front of my eyes. There is no question that this would justify the morning soreness and headaches.<p>My question is: Does the IR light emitted by the iPhone &quot;flood illuminator&quot; have the same effect to my retina even thought I don&#x27;t perceive it?
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StrictDabbler
"If this wasn't IR but visible light it would be like the iPhone's camera
flash going on every 5 seconds right in front of my eyes. There is no question
that this would justify the morning soreness and headaches."

Yeah, but that's because your eyelids would be twitching and your temporal
muscles contracting in response to to flash. When it's IR you can't see it so
your body doesn't do anything in response.

IR light is, in general, very low-energy. Individual photons don't carry
enough energy to disturb chemical bonds. The "flash" you're seeing there is
less bright than a candle. The flickering not bright at all it's just that
CCDs are very good at picking IR light up.

No part of your body can sense or respond to this and even if they did it
wouldn't cause soreness.

The IR "flash" you filmed with your phone is about as bright as a television
remote control. It's literally impossible that this is causing headaches.

Your headaches come from looking at an illuminated object in a darkish room
that's only a few feet from your eyes. Screens in the dark cause eyestrain.

The darker an environment is the more open your pupil is. This reduces the
pin-hole focusing effect of the pupil and requires that the lens of the eye be
more carefully focused to see. Focusing that tightly is difficult because the
lens muscles have to stay in one level of contraction for a long time.

Your body instinctively tries to squint so that the eyelids being close
together and the eyelashes will cause a pinhole effect that will help you see.
The fight between squinting for focus and opening your eyelids to make things
less dark makes your head sore and causes tension headaches. This effect
becomes more pronounced with age.

The first thing you said about PWM? That's a thing people say when they're not
doing so well with cause and effect and cognitive bias. This new thing you're
inventing about the IR is a much worse version of that.

It doesn't have a damn thing to do with the manufacture or components of your
phone. Stop trying to read a phone screen (or look at anything on a phone
close up) in a dark room. That's _it_. Don't do that. It's a thing that makes
your eyes and head sore. It's really well documented. No new explanation is
needed.

~~~
sfilargi
Your post makes sense.

What doesn't make sense to me, and drove me down this rabbit hole, is that I
do the same things with the X that I used to do with the 3GS, 4, 6, 7+ and 8+.
Never had a single problem.

> Stop trying to read a phone screen (or look at anything on a phone close up)
> in a dark room. That's it. Don't do that. It's a thing that makes your eyes
> and head sore. It's really well documented.

True, true. But it doesn't mean that if you sore eyes it's always because of
that.

Do you ever have the feeling of wanting to know what causes something. Not to
prove something, not for any other reason other than figure out why and how. I
am in that rabbit hole. I am very happy with the 8+ and have no eye problems
at all. But I _have_ _to_ _known_ _what_ _is_ _it_ _in_ _X_ _that_ _causes_
_my_ _eyes_ _to_ _go_ _sore_.

~~~
StrictDabbler
The simplest answer is that you're starting to have the very slightest amount
of age-related focus degradation, that it's only manifesting when the room is
very dark, and that it aligned with the new phones by coincidence.

That said, older phones had a higher minimum brightness and more mixed-in blue
light. Your pupils will contract more when looking at a brighter, bluer screen
and smaller pupils focus more easily. Also, being able to see the black part
of the screen can make it easier to focus because you can see how far away it
is.

Normal ergonomic issues like this are probably the cause. Can you get hold of
an older model phone and relax with it for a few weeks to check whether the
problems are really with the new devices?

~~~
sfilargi
Hmm, it may be what you say. Makes sense.

What I have done now is covered the notch with a tape and the strain is gone.
Maybe it is that I got used to it as you suggest.

At some point I will remove the tape and see if the strain comes back or not.

------
snazz
You could try for a week with a little piece of electrical tape covering the
IR light part of the notch and see if it improves. It shouldn’t leave any
residue.

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Rjevski
I believe there is a setting to toggle attention-tracking features, which tell
the phone not to dim the display or lock itself when you’re looking at it. If
you disable it I think this should stop, and along with disabling Face ID it
should turn off the IR light altogether.

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ranuamar
I used my 6s plus at night in bed for extended periods of time without eye
soreness. Switched to the XS Max last month and my eyes have been sore every
morning. Could you try taping the IR emitter and see if that helps?

~~~
willio58
Put some electrical/duct tape over it and give it a try. I'm interested in
what you'll find.

~~~
sfilargi
+1

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cwkoss
Here's an epileptic claiming iPhone X triggered a seizure
[https://discussions.apple.com/thread/8291119](https://discussions.apple.com/thread/8291119)

Many people on reddit claim to have had headaches from their phones, though
some are convinced it is related to the display
[https://www.reddit.com/r/iPhoneX/comments/91krbq/headache/](https://www.reddit.com/r/iPhoneX/comments/91krbq/headache/)

------
waspentalive
Some have suggested covering the notch, as another test you could try watching
your movie with the notch un-covered but with your room lights up a bit - so
you reduce contrast from bright screen to dark background and let your pupils
close somewhat.

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ltmi600
My eyes have been feeling weird lately too. You really have me concerned about
FaceID now.

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avoidwork
I'd turn it off. Our eyes are not meant for IR flashes.

[https://sciencing.com/infrared-light-effect-
eyes-6142267.htm...](https://sciencing.com/infrared-light-effect-
eyes-6142267.html)

~~~
sfilargi
This is with FaceID turned off!

~~~
nik736
Is it the same when turned on?

~~~
sfilargi
Yes. Just discovered, turning the “attention aware features” turns it off.

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jrowley
Interesting question. The same technology (IR laser projector) is used inside
Microsoft's kinect (except they use a stronger projector), and people play
that for extended periods of time, so definitely not the first consumer
electronic to use this type of technology.

There are so many different things that can give you headaches (diet,
hydration, sleep, stress, neurological issues, etc), it can be challenging to
pin this down. I'd say it's more likely something else. Additionally, I find I
get headaches from staring at tiny screens too long in general. I hope you
feel better soon!

~~~
llampx
You're not looking directly into the Kinect though, you're usually looking at
the screen which is a few inches/feet away from the Kinect.

------
uh_what
I was initially skeptical, but your video made me change my mind. Why the hell
is the flood illuminator going off when you're just looking at the Control
Center?

~~~
ksec
I was thinking that too, shouldn't it only be used to unlock Face ID

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aprdm
I don't think it's a good idea to watch movies in an iphone in the dark. Your
eyes weren't build to focus in a small screen full of light in a dark room.
There's nothing good coming out of it.

~~~
sfilargi
True, but it makes me wonder why I never had problems with 3GS, 4, 6, 7+ and
8+. Only when I got the X last year I started having the symptoms.

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King-Aaron
Hey mate, your video is coming up as 'unavailable' for me, interested to see
it however.

~~~
sfilargi
Try this:
[https://www.youtube.com/watch?v=C0Ylyi4wW1s](https://www.youtube.com/watch?v=C0Ylyi4wW1s)

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cwkoss
sfilargi - did you remove the video or was it taken down? Says "Video
Unavailable" now

~~~
sfilargi
Try this:
[https://www.youtube.com/watch?v=C0Ylyi4wW1s](https://www.youtube.com/watch?v=C0Ylyi4wW1s)

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rhinoceraptor
Everyone is exposed to an extremely powerful nuclear fusion IR flood
illuminator every day, it's called the Sun. I doubt the tiny IR LED in your
iPhone would cause any issues.

~~~
NullPrefix
And you have been trained not to look at it. Haven't you?

~~~
rhinoceraptor
Infrared is light, and light is reflected. You don’t need to look directly at
the sun to get get it in your eyes.

