My phone is making me sick and I'm not alone
PWM sensitivity caused by display flickering is a real problem.
It all began one day when I was playing Fortnite with my wife and my son. I was using a Samsung Galaxy Z Fold 4 with my favorite mobile controller — the GameSir X2 — and I noticed my eyes ached after playing for an hour or so. I had just turned 37 two months prior and knew that as I got closer to that magical age of 40, things like this would just start happening.
I told myself that it must just finally be time to get glasses. Can't have perfect vision forever but, as it turns out, my issues had nothing to do with focusing on something close or far away from my face. It all had to do with the type of display I was staring at.
Over the past four months, the problem started getting worse. My eyes would start to ache sooner and sooner and, as of a few weeks ago, I started getting nauseous just *looking* at my phone. It got to the point where I couldn't use my phone for more than 30 seconds without feeling sick and I knew I had to figure this out as fast as possible.
The problem is, there's no easy fix for everyone suffering from this issue, even if I found a bandaid for the time being. If you've been suffering from random headaches, bouts of nausea, or general eye strain after looking at your phone, you might be a lot like me.
What is PWM and why are some people sensitive?
As a huge proponent of OLED displays on smartphones, I was dismayed to find out that my preferred display type was quickly becoming my worst enemy. The issue in question is something called PWM sensitivity — PWM stands for Pulse-Width Modulation — and it has to do with how digital displays dim themselves when operating at below 100% brightness.
In a very simplified fashion, here's what happens. At 100% brightness, all pixels on an OLED display that aren't displaying true black are illuminated. As the display dims itself — usually done automatically on most people's phones as they walk into dark or lighter areas — you might be surprised to find that the pixels don't actually reduce brightness. Any illuminated pixels are always at 100% brightness.
This is a display made up of light-emitting diodes, after all. They're generally on or off. There is no in-between state.
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Instead, any pixels that aren't displaying black will actually turn on and off several times per second to fool your eyes into thinking it is dimmer than it actually is. The lower the brightness slider is on your phone, the more often it'll keep the display off during this cycle. In other words, your phone is acting like a strobe light of sorts.
How does someone like me fix a problem like this? Unfortunately, it's not quite as "easy" as going to the optometrist and getting a pair of glasses. My vision is still 20/20 and there's quite literally nothing wrong with my eyes, despite what some customer service reps from companies might suggest.
As I delved deeper and deeper into the rabbit hole, I quickly found out I wasn't alone. This problem is something that's been brewing over the years but has only gotten worse as display manufacturers like Samsung continually reduce the dimming frequency rate of the display.
Most modern smartphones that use PWM dimming have dropped the PWM dimming rate to 240 Hz which — based on my own research over the past few weeks — is detrimental to anyone with PWM sensitivity. In fact, it seems that most PWM-sensitive folks need to use a display with a PWM dimming rate of at least 500 Hz.
The higher that number is, the less often you'll find someone complaining about being uncomfortable or sick.
The quick bandaid is to leave your phone's brightness at 100% at all times. Obviously, this isn't ideal as it means your phone will almost certainly feel like it's blinding you in a dark room but, until phone OEMs start changing things, this is the fastest solution as it keeps the phone's display from going through the on/off cycle.
It's why I've been using the ThinkPhone by Motorola for the past few weeks which has an OLED display with a 720 Hz PWM dimming rate. That way I can leave adaptive brightness on and still go about my day mostly headache-free.
It's not just OLED
Surfing around forums and subreddits dedicated to PWM sensitivity, I've found that many people tend to blame OLED for their PWM sensitivity issues and yearn for the days of LCD phones.
While it's true that some LCD phones use DC dimming instead of PWM dimming — DC dimming actually lowers the brightness of an LCD backlight instead of flickering it on and off — there are several things phone manufacturers can do to eliminate PWM sensitivity while still using OLED displays.
In the TV market, companies like Sony and LG make their OLED TVs without PWM dimming. This results in a perfectly flicker-free display but, unfortunately for OLED owners, increases the chances that permanent burn-in could occur.
Turns out, one of the reasons companies like Samsung have become so aggressive with lowering PWM frequency is that it helps cycle out OLED pixels which, in turn, reduces burn-in. Ironically, Samsung uses PWM on its QLED TVs even though those types of TVs aren't supposed to suffer from potential burn-in.
Even TCL LCD TVs (like the one I use as a monitor) use a ridiculously low PWM rate of 120 Hz to dim their backlight and some users have reported developing PWM sensitivity because of this.
Even if using a phone with an LCD was an actual solution, no high-end phones in 2023 use LCD. Many of the best cheap phones use LCD but, as you might guess, those phones don't feature the super high-quality cameras or performance of their more expensive OLED counterparts.
Creating a solution
So that leads me to my next question. Why in the world aren't companies like Samsung Display aware of this issue, and what's it going to take to change things? Some solutions like Eazeye solve this in extreme ways by using natural lighting as a backlight, but I have a better — albeit, longer-term — solution.
Noise. Lots and lots of noise.
If you're suffering from headaches, bouts of nausea, or eye strain after looking at your phone, try jacking the brightness up to 100% for a few days and see if that helps. If it does, let us know and let your phone and carrier's customer service team know, too.
Displays don't have to use PWM at such a low frequency. Several Motorola phones, including the Edge 30 series and Razr 2022 all use PWM above 700 Hz. Motorola even sports a flicker reduction option in the display settings, making them one of the most PWM-sensitive-friendly smartphone companies on the market.
Meanwhile, phones like the Samsung Galaxy S23 Ultra and iPhone 14 Pro Max are among the worst offenders on the market with a PWM frequency of just 240 Hz. These phones quite literally make me want to throw up within 30 seconds of looking at one, but it doesn't have to be this way.
As one Reddit user put it, "I got the S23 Ultra and after a week can't use it anymore." That's a huge, huge problem.
And while the iPhone 14 Pro Max is a horrendous offender here, the smaller iPhone 14 isn't thanks to a much lower flicker rate.
In my correspondence with several different companies, most spokespeople had never been asked questions about PWM dimming frequency before and, to be fair, I had never heard of the issue before I began my research about a month ago.
If I'm learning anything here, it's that most smartphone OEMs have no idea this problem exists and the results are phones with inconsistent results.
We reached out to Samsung, but did not hear back in time for publication.
Oddly enough, now that my wife switched from a Galaxy Z Flip 4 — which uses a paltry 120 Hz PWM dimming frequency — to the S23 Ultra, she's started having random headaches and bouts of nausea, too. And no, in case you were wondering, she isn't pregnant.
Samsung, Apple, I know you're listening. You can do better and you absolutely must for the sake of your customers. Even if it's just adding an accessibility option to adjust PWM frequency for users who are susceptible to PWM sickness, there's a real subset of customers who cannot properly use your products because of the displays.
For this reason, I'll be including PWM dimming comments in every phone review I conduct from here on out.
There's even a change.org petition asking Apple to get rid of image dithering and PWM on its phones. This needs to happen and it needs to happen now, before more people end up feeling like garbage on a daily basis and not understanding why.
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LinuxDan2015 Yes! Yes! Yes! Finally some attention on this matter. I really liked my Samsung S20 but in 2021 or 2022 (?) I had to sell it and buy a Motorola G100 with LCD display. No more nausea, dizzy spells and full on vertigo!! PWM must DIE now!!!! I cannot use any OLED phone because of this. I have not tried the newer Motorola's with higher refresh rates, but I'm glad to hear they exist. Prior to my Samsung, I owned an LG phone - it was the one with two displays. I love it, but that only lasted 24 hours. I got really sick with that one and returned it the next day. That's when I started learning about PWM. The Samsung phone took longer to make me sick, but it still eventually did after less than 12 months of use. That's when I went back to LCD. I don't mind LCD at all, but like you noted, you can't get a "high-end" phone with LCD. :-( Moto G100 was the closest I could get and I like it, but still. I want to be able to use any phone I want.Reply
We need to get these companies to hear that people out there are suffering and I wonder how many don't even know why they are suffering. Took me a while to figure it out, that nothing was wrong with me or my eyes but my screens! :-( -
fuzzylumpkin Interesting. Thankfully not something that I seem to be affected by... But the accessibility setting to adjust the modulation rate should already be there, no reason to cause people to suffer when there's an easy fix.Reply -
joeldf
Where do you see that in the accessibility settings. I can't find that on my S20 FE, which I assume is also affected.fuzzylumpkin said:Interesting. Thankfully not something that I seem to be affected by... But the accessibility setting to adjust the modulation rate should already be there, no reason to cause people to suffer when there's an easy fix.
Although, I don't seem to be sensitive to it.
One point made in the article that confuses me. It describes how these OLED screens dim by alternating scan lines. And saying that when a sub-pixel is lit, it's fully lit.
So how does it handle really dark grays while, say, displaying a photo, or while browsing this forum in dark mode, while at overall full brightness?
There seems to be a disconnect in how different shades and brightness is handled at the same time. -
fuzzylumpkin
When I said it should be there, I meant it should be there and not it is there. As in, if it's something that can be done then they should do itjoeldf said:Where do you see that in the accessibility settings. I can't find that on my S20 FE, which I assume is also affected.
Although, I don't seem to be sensitive to it.
One point made in the article that confuses me. It describes how these OLED screens dim by alternating scan lines. And saying that when a sub-pixel is lit, it's fully lit.
So how does it handle really dark grays while, say, displaying a photo, or while browsing this forum in dark mode, while at overall full brightness?
There seems to be a disconnect in how different shades and brightness is handled at the same time. -
joeldf
Sorry. Misunderstood.fuzzylumpkin said:When I said it should be there, I meant it should be there and not it is there. As in, if it's something that can be done then they should do it -
jimmy_uk Thank you for a mainstream report on PWM. Temporal dithering is also a huge issue to be aware of. For too many years I and many others have been met with comments like "get your eyes tested" or "you need glasses".Reply
I've realised I'm sensitive to PWM and temporal dithering since the release of the iPhone X. I've been an avid iPhone and iPad user since they were released and the X was a big change to the iPhone I had been looking forward to for years. Within an hour of use, my eyeballs felt like someone was stepping on them and I got a nasty migraine. Since then I've been unable to upgrade to any flagship iPhone that uses OLED as I always end up with the same result. This is soul-crushing as I love technology and mobile phones play a big part in our daily lives. I've had to settle on an iPhone 11 as this is LCD with no PWM. It's fine but it's not a flagship and maybe the last iPhone I will ever own with the way things are.
This is also an issue for me on the iPad Pro's. Since Apple started using "liquid Retina" displays they have introduced PWM to some iPads and the ones without it still have temporal dithering which means the pixels are moving to get the 10bit colour through fakery. This also causes eye strain for me despite them using LCD. MiniLED also has PWM. Sigh.
Samsung, LG and BOE as manufacturers of these displays are most definitely aware there is an issue for certain users, how could they not as people like myself have been taking about it in forums for at least 13 years. They must just figure the number of people affected is too low (but imagine the number of people who don't even realise their devices are making them feel ill). Apple will never publicly acknowledge these issues as it could open up lawsuits. -
Morty2264 I've never heard about this happening before -- it sounds terrible! Thanks for the information!Reply -
Stanley Kubrick I have read about this several times over the last few years. I appear to not have the issue. Sorry for those that do.Reply -
asus389 I'm glad to see this article. I have been using screens since the 1980s and never had any issues until a few years ago. It seems all OLED phones cause me to have headaches, eye strain, and nausea. This effect is worse at lower brightness levels (and higher levels of flicker) consistent with irritation from PWM. I am holding onto my older LCD smart phone because I can use it with no issue, but I am worried I will be locked out of newer devices unless this issue is somehow addressed.Reply
I have also noticed that some LED/LCD panels can cause a weird eye strain/spaced out feeling for me as well. I think that's down to temporal dithering, which is more common now as electronics companies seem to be using more screens that are 8bit+FRC to show HDR or wide color content. I suspect it could be resolved by using actual 10bit displays. I'm not sure why they don't.