macsforme Hi, yes, that is exactly what they did. I read an article on mrmacintosh.com about downgrading firmware to a specific version, downloaded 13.2.1 ipsw file and brought all this to a service center, where they uploaded the entire image using another Mac. As a result both "system firmware" and "OS loader" reported by system information matched the ones for Ventura 13.2.1.
I'm testing as many MacBooks as possible. Here are the results.
I finally was able to execute on a 2019 MBP 16-inch w/ Intel and AMD Radeon Pro 5600M. I got the below from terminal (the Intel response a lot longer than your above). It seems like dithering is disabled on both, right?
My eyes are a bit tired from messing with so hard to tell right now on symptoms, but…
For the AMD:
And for the Intel:
- Edited
GregAtkinson For comparison I used the white ledstrain background from chrome. I will try some other colors.
In the meantime, I will add these graphs:
Iphone X IOS 14 (perfect for my brain):
Ipad air 2 (ledstrain white with safari) the only ipad tried that does not give migraine problems but I am stuck with IOS 13 for fear of updating:
Finally the business laptop which is an HP elitebook 840 g8 that destroys me in an hour of use (again ledstrain white with chrome):
From these graphs I cannot find any logical explanation with my symptoms. Because the HP should be the best and the iphone X the worst instead for me it is exactly the opposite.
The only thing I know is that it is a software problem.
Lauda89 That is very interesting. Here's a few ideas/questions:
The flicker rate on your iPhone X is 250 hz (it flickers every 4 ms), which is well above the level that most people will get headaches. So maybe you're not sensitive to OLED flicker or any kind of flickering at high speeds (say, 100 hz or higher).
So if you ignore the huge dips and just focus on the top line of the graphs, you'll see a correlation between headaches and the variability of the graphs. Note that when comparing these graphs, you have to keep in mind that they have different scales for the Y axis, so you have to imagine what the graphs would look like if they had the same scale.
Iphone X (no headaches, pretty flat if you imagine what the graph would look like if the Y axis went up to 250 and not just 100.)
Macbook (no headaches, pretty flat)
Gaming pc (headaches, pretty ragged)
I find it really interesting that the output from your Macbook and gaming PC have different brightness levels and that the gaming PC has a more ragged line than the Macbook. I would start looking for differences in how the display works. I think you'd mentioned that one of them connects via HDMI and the other via DisplayPort. That could be worth experimenting with. But also you could look in the monitor settings (are these devices somehow using different monitor settings?). And also for the graphics card you could play around with different settings like make sure you turn off "eye care" and blue light filters and things like that. The good news is you can make various changes and test them immediately with your light meter.
Testing with other colors, especially light gray and light green could be interesting. Something called pixel inversion happens at 30 hz and many monitors flicker worst with light colors vs pure white.
Lauda89 Oh, and have you tried turning off your discrete graphics card and using your integrated graphics card on your gaming PC?
@NewDwarf thanks again for your help on this!! I have a Rx 5600 Xt in an EGPU exclosure do you know what commands I'd need to disable dithering on that please?
DigDeal Sorry to hear the firmware downgrade did not work for you. 
I wish there were better methods for empirical measurements of these problems (I see there are some hopeful developments in other threads here recently). Because of this, it can be hard to determine whether some irreversible changes are occurring during software updates (not limited to the main firmware), or if our brains now associate the whole device with being a threat, even after reverting to the previous, tolerable state. I hope our continued research here will ultimately bring some clarity.
@GBowler noted different levels of eye strain between two identical MacBook models with different installed firmware versions. I also have several MacBooks of the same year (2015), which all had recent firmware versions, but among them I find certain screens more tolerable than others. So, while firmware remains a possible factor, I am currently leaning more toward attributing my personal issues to panel variations.
i think laptops with ips lcd screens would cause the least eyestrain?
RobC Unfortunately, all display EDID values for this MacBook model/year appear to be identical. 
My understanding is that Apple removed the ability to see the display model/vendor after people were returning earlier retina MacBook models which did not come with a display from their preferred vendor.
macsforme I have been investigating reports of eye strain on MacBooks being triggered by a firmware/OS update. I also bought a few tools to dump and flash different firmware versions on MacBooks (specifically testing the MacBooks I have, which are mid 2015 15-inch Pro models, both with and without the discrete AMD GPU). So far I cannot pin down the issue, but there have been several reports like yours and I plan to keep investigating. A GPU VBIOS update seems the most plausible.
This might not be possible, because it requires a "known good" system of the same model but in that case it might be possible to compare firmware dumps between a "bad" versus "good" system and potentially identify what's different.
From what I remember (almost) all laptops integrate the GPU VBIOS into the UEFI ROM image, as opposed to desktop GPUs where the GPU VBIOS is flashed onto a separate chip, so identifying or changing the VBIOS in use can be done with external tools.
macsforme yeah, pretty sure at that stage it's at least partially psychological. I'm literally scared to update any usable device at this point.
Interesting note, again proving my point that it's 100% software related, is that using "safe mode" makes it tolerable. Not ideal, but not as harsh as in regular mode. Most likely some sort of hardware acceleration is disabled.