iPhone 17 Models Include Toggle to Disable Screen Flickering (PWM)

[Brapple]

60/75Hz iirc was what most CRT could handle and was in settings, and oh to stand aloft, in an open plan office looking out over a sea of flickering screens.

No one ever noticed. Except me.

Same. 85hz was the mainstream top-end CRT. I managed to surround myself with those as they were the best I could find. I could work on 85hz all day and still stay sane. 60 and 75 were headache / nausea inducing within a short time.

And yes, I could spot when someone had their 85hz screen misconfigured from across the dept. Windows would often revert back to 60hz for stupid reasons.

Do you remember the era of high-end rear-projection TVs? Big time blurry flicker-fest those were - even the $6,000 Mitsubishi Diamond ones. Then DLP sets came out with their own issues. Mirrors!

 

[Jensend]

Agreed, though I almost consider it a case of PWM-sensitive people having more capability (not a disability) to detect the flickering which is why they're affected. For me it wasn't Covid - I've had this sensitivity for decades. For example, when I first started in IT in the mid-1990s people of course used CRT monitors and I could immediately tell visually when someone's monitor was set to 60Hz as opposed to 72Hz. I'd tell them to check their settings and "fix" it since 72Hz is better for them and every time I was right.

Disability or superpower is irrelevant. I just hope they fixed it.

I can't use 60Hz pulsing displays, and 72/75Hz has noticable flickering for me, especially in my peripheral vision.

Discomfort with PWM on modern displays is categorically different. At ~75 Hz and below, flickering is directly visible. At ~90Hz and above there is no visible flickering (this is part of the reason many VR headsets choose 90Hz as the default—they use pulsed displays).

At the much higher pulsing rate of modern screens, I believe that most of the discomfort is due to eye movement: saccades. Usually when you vision jumps from one point to another, there is a blur that averages out the brightness of the scene you are viewing and your brain can hide that transition period. With a pulsing display, you instead see a bunch of sharp intermediary images that your brain has a harder time ignoring.

Discomfort with 60Hz flicker may not be linked to discomfort from 240Hz flickering.

 

[pdoherty]

At the much higher pulsing rate of modern screens, I believe that most of the discomfort is due to eye movement: saccades. Usually when you vision jumps from one point to another, there is a blur that averages out the brightness of the scene you are viewing and your brain can hide that transition period. With a pulsing display, you instead see a bunch of sharp intermediary images that your brain has a harder time ignoring.

You might be onto something there. I guess a way to test that would be to leave a static image onscreen and simply stare at one thing on the screen for however long it usually takes for PWM symptoms to happen and see if they still do.

 

[Populus]

Just a FYI: the new M5 OLED iPad Pro doesn’t have this toggle. It uses PWM at its fullest.

 

[dakicka]

I had NO eye issues until updating my 16 Pro to iOS 26. Now I have severe eye strain, recurrent headaches, and nausea. This is absolutely ridiculous. I’m convinced Apple added this so people will upgrade to the newest phones. Class action lawsuit incoming.

 

[JM]

Got a 17PM about a month ago, and while I don’t get headaches or nausea, I do get the burning eye sensation (which I think is more do to temporal dithering, as I get burning eyes for all P3 wide color 10bit displays whether LCD or OLED)

I thought the TDithering only occurred on LCD but it seems OLED does to?

Anyways, wanted say that after using the PWM off, I’ve noticed that I don’t get these flashing dots anymore in my peripheral vision or when my eyes are closed. It was like I’d get a laser dot flash every once in a while: just a single bright flash point.

My night vision is a LOT better too. Before I was just dim vision in low light all the time.

I haven’t had any laser dot flashes since the 17PM. (I had a 14pro before… no idea what screen it was, but tolerable OLED flickering) and my night vision is better too.

Right now I’m trying to figure out if True Tone on or off is more comfortable. The yellow of True Tone seems to be more comfortable than the bluish tint of it off.

 

[uacd]

Got a 17PM about a month ago, and while I don’t get headaches or nausea, I do get the burning eye sensation (which I think is more do to temporal dithering, as I get burning eyes for all P3 wide color 10bit displays whether LCD or OLED)

I thought the TDithering only occurred on LCD but it seems OLED does to?

Anyways, wanted say that after using the PWM off, I’ve noticed that I don’t get these flashing dots anymore in my peripheral vision or when my eyes are closed. It was like I’d get a laser dot flash every once in a while: just a single bright flash point.

My night vision is a LOT better too. Before I was just dim vision in low light all the time.

I haven’t had any laser dot flashes since the 17PM. (I had a 14pro before… no idea what screen it was, but tolerable OLED flickering) and my night vision is better too.

Right now I’m trying to figure out if True Tone on or off is more comfortable. The yellow of True Tone seems to be more comfortable than the bluish tint of it off.

I use TrueTone on mine, no issues.

Disabling temporal dithering is fairly simple. You need to turn off all HDR content in your phone. In Photos app you need to deselect “full HDR”, disable HDR video recording, force all apps to use SDR by enabling battery saving mode (some apps do not support disabling HDR in settings).

Additional brightness used for HDR also uses dithering to emulate 2 additional bits of color.

Beware that all photos that iPhone camera takes by default have HDR version, so you either shoot RAW and edit without HDR or just watch the SDR version (which sometimes looks dull and plastic because of Apple’s overprocessing)

 

[JM]

I use TrueTone on mine, no issues.

Disabling temporal dithering is fairly simple. You need to turn off all HDR content in your phone. In Photos app you need to deselect “full HDR”, disable HDR video recording, force all apps to use SDR by enabling battery saving mode (some apps do not support disabling HDR in settings).

Additional brightness used for HDR also uses dithering to emulate 2 additional bits of color.

Beware that all photos that iPhone camera takes by default have HDR version, so you either shoot RAW and edit without HDR or just watch the SDR version (which sometimes looks dull and plastic because of Apple’s overprocessing)

Thank you

And your description of HDR photos is perfect 🤣

I reeeaaaallly don’t like the non-HDR photos.

 

[MICHAELSD]

Unfortunately, the long-awaited PWM toggle didn’t do enough to create a more stable waveform or reduce modulations to flicker-free levels. Accordingly, I remain unable to use a modern iPhone without severe persistent headaches.

I’ll hold out optimism for iPhone 18 Pro as that’s all I can do. At least the introduction of an Accessibility setting was a step in the right direction. A sufficient PWM toggle would have to be more efficacious and comprehensive.