A
AshX

AAshX · 2025-04-11T16:08:00+00:00

RecentlyDeceased666 Covid still doesn't explain why my two old tvs are so easy on my eyes.

When I got COVID in 2022 my Plasma TV from 2012 was fine. It has PWM. My 2019 iMac was not fine until I used SwitchResX to force it into 8-bit mode. Then it was tolerable again until I got reinfected in 2024.

The issue is COVID, because COVID crosses the blood-brain barrier. Take a look on the long COVID subreddits. Lots of folks with the exact same experience.

So why is your old tech fine? The same reason my TV was fine: there’s something about newer screens that we have become sensitized to post-infection. For some it’s PWM, dithering, polarization, blue light - probably a combination of all of the above. It doesn’t mean we didn’t have issues pre-COVID, it just means as I saw someone describe it, we probably had a higher tolerance and wrote it off as “using the computer too much” or “blue light.”

I think for many it can also be a matter of software and hardware increasing whatever elements we find irritating, so it doesn’t necessarily mean COVID or another infection is always the trigger. All I can tell you is that in my case, I could tolerate MiniLED, strobing lights, and Apple tech prior to getting sick. I do remember finding the iMac Pro in 2017 uncomfortable, and I now know that computer had PWM, but I could use it.

I’m just throwing this out there because of how suddenly your issues appeared. It was the same for me. That being said, at this point the only thing we can do is find specific pieces of tech that work for us, and use software tools like Stillcolor and BetterDisplay to hopefully deal with the software triggers on computers. I, too, can’t tolerate modern TV’s.

AAshX · 2025-04-11T03:40:07+00:00

I believe I commented on your Reddit post. As OP indicated on Reddit, his issues began after a COVID infection. I’m 32 and when I got COVID in 2022 at age 29, I started to be sensitive to flicker. I got re-infected this past summer and it made things worse.

I know some folks don’t went to talk about it, but a lot of us with long COVID have issues with screens and lights. If what you commented on Reddit was accurate, OP, then that’s why suddenly you’re having issues.

As to how to resolve it, well, it depends on if what’s wrong is something like binocular vision dysfunction which some long haulers developed. I believe there are exercises you can do to improve that.

Otherwise, as with myself, I’m trying to narrow down what exactly is triggering things for me, and to find a computer screen that is usable.

AAshX · 2025-04-04T15:32:42+00:00

What computer are you using (model, specs, OS)? Are you using an external monitor that perfectly scales with MacOS? There are very few external displays that scale perfectly with Macs - specifically 27” 5K displays like the Apple Studio Display. Anything else will cause blurry text, icons, shimmer, etc.

AAshX · 2025-04-04T04:25:44+00:00

I’ve been looking at the newer M4 computers, reading different experiences across the interwebs, downloading the app and trying this and that in settings, color profiles, etc. I’m curious what everyone’s experience has been on the M4 models and MacOS Sequoia, because Stillcolor seems to have no or minimal effect. In some cases it seems to make things worse.

Has Apple changed the way they’re processing dithering with software with the new OS and chips? Have they resorted to hardware dithering on the screens themselves? To my understanding there was a lot of success, particularly with the M2 generation, with Stillcolor. Is there any way to test this?

AAshX · 2025-03-26T20:22:39+00:00

Donux

I also noticed this discrepancy in store. Interestingly I found the more washed out screen to be more comfortable. The brighter screens clearly had a calibration problem, too.

If you look at various topics on MacRumors or even Reddit, there are complaints going back to M1/M2 about screen quality. The custom builds particularly had a backlight problem where the piece holding the screen in place created an indentation on the screen.

Clearly you’re going to deal with the screen lottery. As to PWM no one is able to confirm or deny it.

I haven’t had a chance to pick one up myself yet, but I think it’s going to be difficult to hone in on what - if any - of the MBA models are worth it.

I think we are also discounting the role MacOS versions play. Each generation is limited to the OS that it ships with. In other words, you can’t run Monterey on an M4. And it seems like the trend is that each subsequent interation introduces more visual problems in an attempt to make the screens appear more competitive.

It’s very easy to feel like we are chasing windmills because other than the guy who made Stillcolor, everyone is just guessing. I still have yet to see enough evidence that Stillcolor is as effective on the M4 chips as it was on the M1-M3 generations.

Unfortunately I’m not a programmer, otherwise I’d be diving into what could be causing all this. So we are relying on the benevolence of those with that skill set devoting hours to dissecting the inner workings of MacOS.

AAshX · 2025-03-26T20:10:15+00:00

I would also like to know this. As a new user it’s overwhelming browsing these forums. It feels like with the exception of the Stillcolor thread, there’s not been much progress. I’ve combed through hundreds of posts and often the useful things are sprinkled here and there in replies to threads with hundreds of other replies, often years old.

It would be helpful if the mods or veteran users could start creating master posts with helpful tips and protocols that they’ve used over the years for different machines. Otherwise it starts feeling like a game of telephone.

AAshX · 2025-03-22T07:34:15+00:00

simplex Best way to check is display true 8-bit, to run it in 6-bit keeping disabed GPU dithering. If you feel better, the monitor is 6-bit with agressive FRC. All monitors/screens 2k75 / 2k165 / 2k120 / FHD 60 / FHD 100 I tested were 6-bit, I am not sure 8-bit exists

This is very interesting.

It seems like the effect is cumulative, then. Perhaps there is a threshold unique to each individual which they can tolerate. Why were many of us able to tolerate less-than-perfect monitors in the 2000s/early 2010s I wonder.

In theory, then, software updates to the OS or GPU could alter the dithering frequency and/or intensity? I wonder why many update the OS on both phones and computers and suddenly the device causes discomfort.

There is too much obfuscation for the sake of marketing and sales. It’s clear Apple is the worst offender the past decade.

AAshX · 2025-03-22T05:55:08+00:00

simplex

Is there a standard equation used to determine FRC freq based on refresh rate? Or is it dependent upon the software?

Anecdotally this makes sense. I tried the Lenovo Yoga Slim OLED. It was most comfortable at the 90Hz selection - both 120 and 60 were uncomfortable. Settings page claimed it was an 8 bit display. It does have PWM, though.

I did a side by side test of the Apple Studio Display with a Mac Mini and a Mac Studio M3 Ultra. The Mac Studio was infinitely more comfortable than the Mini. The Studio Display is locked at 60Hz so I have no idea what is going on with that other than a difference in dithering algorithm or that the Macs are genuinely not able to consistently run 60Hz and are throttling.

AAshX · 2025-03-22T04:03:38+00:00

amusesmile

I tried Stillcolor on 3 MBA 13” M4 laptops at Best Buy and it actually made the screen worse. It was more uncomfortable, with both dithering and uniformity 2D disabled.

I would love for more people on M4 to see if Stillcolor is actually working. I’m still yet unable to pick up one myself to try, but the results were not encouraging. I wonder if Apple somehow changed the protocol with the M4 series chips.

AAshX · 2025-03-22T03:52:36+00:00

JTL

I read up on that before I posted this. I also read the posts trying to disable dithering on AMD GPUs on intel Macs and no one seemed to have had any luck. Since the Apple Silicon M-series was released any interest in the intel Macs seems to have evaporated.

I have not updated this computer since I updated into that version of Mojave when it was released. So there’s no way any firmware was updated. I had a family member look at the screen and they said it’s fine, so clearly this is a “me problem.”

My question then becomes: what is this flicker? Is this the 60Hz refresh rate? Or is it dithering at half that rate? Or is this some sort of LED backlight PWM from the mid-2010s screens? I’ve read conflicting reports that the MBP 15” 2015 has PWM. It wouldn’t surprise me if the iMac did as well since the 2017 iMac Pro 5K 27” had PWM at a very low frequency.

My guess is this is PWM or a dithering flicker. I don’t know why PWM would be present with auto brightness turned off, but I don’t presume to be an expert. Dithering makes more sense since SwitchResX doesn’t seem capable of fully disabling it, but switching from billions to millions of colors does allow me to look at the screen longer than without. I could decipher what this is I think I’d at least know what to avoid in the future.

I suppose I could try buying an external monitor and seeing if the issues persist?

AAshX · 2025-03-22T03:44:48+00:00

The issue I’ve noticed that I have with panels that are over 60Hz is that they rarely stay at 120Hz, for example. The MBP line is notorious for this with ProMotion. There’s a lot of downshifting/throttling going on, especially in laptops. In that case it’s worse.

I bumped into a regional manager at Best Buy who knew all about PWM. We talked for a while and he said that I needed something “faster than my nervous system” so that I wouldn’t be symptomatic. He recommended 240 if possible.

I’m not sure if I buy that because I also find 60Hz more comfortable. I also think a lot of factors like dithering, blue light, text rendering, and a general sensitivity to lights complicates this. I looked at one of the recommended high refresh rate monitors and it was just overkill at 32” and way too bright.

It also depends what tasks you’re going to be performing. Gaming, video editing, music production, and coding are vastly different. So maybe certain use cases are better at certain refresh rates.

AAshX · 2025-03-22T03:38:24+00:00

parawizard

Was it a Sky Blue model? I noticed the other colors had screens that did just that. It almost seemed like they were out of focus. My best guess is dithering or something hardware based.

AAshX · 2025-03-21T00:03:05+00:00

Checked another panel. Same ending suffix G2A. Can confirm despite this there is a difference in quality screen to screen, even on the Sky Blue, though it is better than the other colors. Not sure how to feel about it. Stillcolor also seems to make things worse if you can believe it.

"raw-panel-serial-number"=

<"FP1HD6003X30000G2A+A+5A2F4Z0330B5BA+PR

OD+Y452550125015+Y12541117Y01941119+449T2437GJ29309A4BD438H0004AJ49W06610J8A5146

460+B25025108502710150271K50272150272D50273015027295">

demouser@DM026NYGXQ-MacBook-Air ~ %

AAshX · 2025-03-20T19:01:55+00:00

DisplaysShouldNotBeTVs

No, I didn’t update the OS which is what makes this even stranger. It has been on Mojave since release and I haven’t installed a single update. It remains unchanged from when I last used it in June 2024.

I was reinfected with COVID in July 2024, and already had long COVID and other health issues previous. My best guess if the machine is normal is that my tolerance has evaporated completely. I’m wondering if certain long COVID symptoms were actually neurological symptoms from working on this screen.

My iPhone 13 is tolerable despite having PWM. I’ve been using it every day throughout all these illnesses so I wonder if it allowed me to neurologically handle this particular phone, and the difference between the two is too great. Or maybe I just got lucky with this phone screen and the iMac is deteriorating with age. Your post gives a lot of food for thought.

AAshX · 2025-03-20T14:31:20+00:00

Rikl see if you can find a sky blue 13” in person. My situation is identical to yours. It’s really hard for me to even judge because of the horrible flickering LED lighting in Apple and Best Buy, but I think this one might be a possibility.

AAshX · 2025-03-20T06:00:24+00:00

Clokwork

Is there a way to measure this without buying an Opple Light Master? I’ve searched and searched and can’t find any data on these models having PWM, other than a few forum posts claiming both iMacs and MBP’s from the 2015-2019 era having obvious flicker and PWM.

I wondered if this was just the normal 60Hz refresh rate…but then why do the MacBook Airs from the last few years not seem to have this flicker yet are also IPS LCD screens? It seems to be constant regardless of brightness. Am I mistaking something normal for these displays as being an issue…or is this some sort of constant LCD PWM flicker?

Dithering was traditionally what caused me issues with the iMac after a COVID infection, but SwitchResX seemed to largely resolve that. I haven’t used the computer in nearly 9 months, so I wonder if this is a new sensitivity. I start getting dizzy just even looking at the iMac for a few seconds. Quite concerning.

AAshX · 2025-03-20T00:17:25+00:00

MAS-76

I believe I was correct. I just went back today. The Sky Blue panels end in G2A and the Silver ones end in G29 in the first string of code.

From the most recent store:

Sky Blue 2:

"raw-panel-serial-number"=

‹"FP1HD20049Y0000G2A+A+5A2F4Z0337A9DF+PR

OD+Y452550115015+PA18R1201Y21941114+44924G509414380004A4906610J8B4BX5

012+B25022208502310250231M50231150232D50232015023295">

demouser@CXCDG3G4FK-MacBook-Air~%

Silver:

"raw-panel-serial-number"

<"FP1HD100BYD0000G29+A+5A2F4Z0247B8GD+PR

OD+B451645245011+PA18R1201Y51141104+446T2432GH54000A4AK433Y0004AJ492065401184BEK

184+25021308502220150222M50222150222D502220150222B5">

demouser@M7F6K203YN-MacBook-Air~%

I could be wrong and this could just be a signifier for each color but I feel like I’m not. When I tell you the difference is night and day, it is. This only applies to the 13” Sky Blue. The 15” Sky Blue is still bad though not as bad as the other 13”s.

I am going to bite the bullet and buy a 13” Sky Blue from Apple. I’m going to get the 16GB/512 GB option because it has more GPU cores in the hope that it will be less prone to dithering. But I am starting to feel like this is a screen manufacturing problem.

I will report back later this week, both once I have the 13” to test in a better lighting environment and also on the upgraded 13” to see if the better GPU helps or hurts things.

I know I’m mostly relying on my intuitive hunch here guys, but I’m desperate because I’m striking out with every other computer and I need something for work. Of course 13” is tiny and finding an external monitor will be a whole other problem, but it would be nice if we could have access to an M4 machine that is tolerable.

AAshX · 2025-03-19T22:49:54+00:00

I’ve been having issues with a 2019 21.5” 4K Retina iMac. Really bad headaches, dizziness, and eye pain. I was given a 2015 MacBook Pro to try and while it’s a little better, I do get similar symptoms after a while.

I recorded videos of both at 240 fps and there seems to be a flicker at all brightness levels. I booted the iMac into Safe Mode and the flicker was still there, reset the NVRAM, etc. No help. I also recorded videos at 120 fps and the flicker is also visible.

Is this a normal sort of thing? I don’t think this is PWM since I thought the 2017 iMac Pro was the only one with PWM? I’ve used SwitchResX to change to “millions of colors” on the iMac, and while it helps a little with focusing on text (it was very easy to focus on text in Safe Mode), it doesn’t resolve this flicker. I assumed this might have been wear and tear, the GPU going bad, etc…but now I’m not so sure? I’ve linked videos of the 240 fps videos below. Would love to get some feedback.

iMac: https://streamable.com/nx4vd5

MBP: https://streamable.com/sxkrio

AAshX · 17 Mar

macsforme

I downloaded Stillcolor on the new MacBook Air computers and the M4 Pros all running Sequoia at the store and noticed no difference. Unless display units are somehow locking programs out (Stillcolor successfully installed) I wonder if the new OS applies other forms of dither or if it introduces new features that cause discomfort.

We need more data as to whether or not Stillcolor is only effective on certain MacOS versions. I wouldn’t be surprised since the trend for both MacOS and iOS since 2021/2022 seems to be more intense dithering and other yet-undiscovered software gimmicks that make screens more uncomfortable and difficult to view. If this is true, either @aiaf might be able to run some tests on the latest OS and MacBooks, or we just have to compile a list of hardware and corresponding MacOS versions that Stillcolor effectively tilts the scales in a positive manner.

This is such a difficult problem to solve because just when you think progress has been made, Apple introduces new software that seems to undo all the progress. It’s like playing whack-a-mole. I’ve read about serious quality control problems with the MBA line going back to the M1, and I’ve seen it myself with the latest M4 models. So clearly there is a hardware defect component that is affecting folks. Trying to determine where hardware or software begins and the other ends is a real challenge.

AAshX · 17 Mar

NewDwarf

MAS-76

I went to yet another Best Buy and tested the suggested code in terminal. I will go to the Best Buy with the model I found most comfortable tomorrow to compare, but here are the results.

Sky Blue 13” M4:

"raw-panel-serial-number"
<"FP1HD40066S0000G2A+A+5A2F4Z0172A5CH+PR
OD+Y451545244527+Y12241103Y01941119+449T2437GJ29309A4BG438H0004AJ49W06610J8A5137
981+15024108502430150243M50251150261D50261015026195">

Silver 13” M4:

"raw-panel-serial-number"
<"FP1HD90004G0000G29+A+5A2F4Z0452B1EC+PR
OD+B452750135021+P820R1217Y91941122+449T2437GJ53909A4AH443H0004A340M06610J8A5183
388+C25031224503310950331750323850323U50331085033105">

Once again, the Sky Blue was more comfortable, but less comfortable than the previous unit at the other store. This could be because they had abohr the worst overhead fluorescent/LED lighting I’ve ever seen. I could not even look at the carpet it was so bad.

And I can also tell you all it is not placebo because of my COVID complications my left eye is incredibly sensitive to light and flashing lights of any kind and will protectively shut when exposed. So it’s a sure way for me to tell within 5 seconds whether a screen is uncomfortable.

All this being said, that doesn’t mean I - or any of you - will be able to tolerate this computer over a long period of time. I’ve been going to stores because I need a Mac for work and I’m trying to rule out these computers before I waste my time buying them and returning them. Like I said, I can tell almost immediately whether I can tolerate a screen so I don’t need to take several days to see, unless the computer causes very minimal issues in which case I’ll put it through the paces. But I’ve not been able to find one in 2 years.