Greetings. This is my first post here on this forum, I am very glad a place like this exists for discussion around eye strain topics for those of us who are affected. Recently, I recorded many devices in hopes of detecting any anomalies, mainly flicker that would suggest temporal dithering or PWM, as they seem to be the main factors that contribute to eye strain, at least as far as I know. I figured I would post this information here because I’m sure I’m not the only one who may find this information useful.

My testing methodology consists of recording the subject device in a dark room at 100% brightness with a 10% gray image loaded on the screen, the video I use is found HERE. I use an iPhone 13 Pro Max as my recording device as I found it has the best slow motion camera out of all the phones I have access to. I record the subject device at HD 120 or HD 240 fps, and view the video for any amount of flicker and quantify that amount. Note this methodology is not completely scientific, as I am measuring the flicker with my eyes, not equipment that can generate a number. Regardless I find this method reliable for me thus far.

Here is a key.

  • 0 - No flicker

  • 1 - Barely perceptible

  • 2 - Visible but minor

  • 3 - Clearly visible, but not excessive

  • 4 - Clearly visible, excessive

  • 5 - Very visible, very excessive

  • 6 - Full on strobe light

**
And here is the data.**

Hd 120fps

  • 4 - M1 Macbook air (all OS’s)

  • 4 - 10th gen iPad

  • 2 - iPad air 2 2014 (ios 13.3.1)

  • 1 - iPad air 2013 (ios 12.5.6)

  • 0 - 2018 HP Envy x360 15” laptop

  • 0 - Tab S8 LCD (one ui 4.1)

  • 6 - S22 Ultra (one ui 5.0)

  • 0 - AD27QD monitor

  • 0 - iPhone 8 Plus (ios 16.2)

  • 5 - Switch Lite / Standard Switch (LCD)

  • 0 - iPhone 11 LCD (iOS 15.6.1)

Hd 240fps

  • 3 - iPad air 2 2014 (ios 13.3.1)

  • 4 - M1 Macbook air (all OS’s)

  • 4 - 10th gen iPad

  • 0 - Tab S8 LCD (one ui 4.1)

  • 2 - iPad air 2013 (ios 12.5.6)

  • 1 - AD27QD monitor

  • 0 - iPhone 8 Plus (ios 16.2)

  • 5 - Switch Lite / Standard Switch (LCD)

  • 0 - iPhone 11 LCD (iOS 15.6.1)

**
Below are devices that I have used extensively and have a subjective measurement of eye strain on.**

  • iPad air / air 2 - Little to no strain after excessive use

  • M1 Macbook air - Causes moderate eye strain after 30-45 min (Tested Big Sur, Monterey, and Ventura)

  • 10th gen iPad (ios 16) - Severe eye strain / headache after 10 min. Worst screen I've ever experienced.

  • S22 Ultra - Dry eyes / burning sensation after 10 min, less straining than 10th gen iPad for some reason.

  • PC monitor (AD27QD) - Zero strain after many hours

  • iPhone 8 Plus (iOS 16.2) - Zero strain after 1+ hours

On a side note, I initially believed Apple rolled out temporal dithering to all iOS / iPadOS devices around mid 2021, around the time my 10.5 iPad Pro became painful to use (sold it), but the fact that the 8 Plus I tested on iOS 16.2 shows zero flicker suggests otherwise. I will also be testing an iPhone 11 (LCD) soon, and will post my findings here.

    What's strange is that Notebookcheck did not find flicker for the iPad 10 (2022). They may not have searched thoroughly enough though, which has happened in the past.

    Everyone should have a look at the oscilloscope thread: https://ledstrain.org/d/312-homemade-oscilloscope-to-detect-pwm-diy-guide

    I think if more people get flicker detection equipment, we can find more info than Notebookcheck does.

      Brendan970

      Thank you for posting this. I’m surprised that the 8+ on iOS16 showed no flicker, as I and some others noticed issues when we upgraded to iOS15. I’m curious if they fixed something in 16, or the flicker isn’t showing up for some reason.

      Definitely curious what the iPhone 11 will show. Also, do you have access to the iPad Air 5 or MacBook Air M2? Those apparently have no flicker according to notebookcheck, it’d be interesting to see what they show.

          KM If you look at Notebookcheck's video on temporal dithering for the iPad 10th gen you can clearly see some kind of flicker or alternating phenomenon with the subpixels, especially the blue ones. I definitely think they missed something. I bought the 10th gen iPad because they claimed it was free of flicker, but it seems they may be wrong.

            bkdo I tested the 8 Plus on iOS 15.5 before I updated it to 16, and I found no flicker on 15 either. However, I think the iPhone 8 Plus I am testing may have had a screen replacement in the past because I just noticed I cant enable true tone, suggesting a replacement. Temporal dithering should be software only as far as I'm aware, so I would think a replacement OEM screen would behave like an untouched one, but I may be wrong.

            I don't have an Air 5 or M2 air, but I'm almost sure the M2 air would be just as bad or worse than M1 air in terms of eye strain. See this thread on the M2 air, it looks worse than M1 to me.

              KM For detecting issues other than PWM/alleged DC backlight fluctuations on certain devices I think using an oscilloscope and photodiode is barking up the wrong tree, because a photodiode only measures intensity of light.

                KM FWIW, I found the iPad 8th gen to not have much eye strain for me. IDK if you can still get ahold of one, but it's worth a try. I think it was running iOS 14.8.1 when I used it. IIRC it uses an A12 SOC and the display is the old type that doesn't do P3 or True Tone. I don't have the equipment to test it and compare it to the 9th and 10th gens.

                  I just tested an iPhone 11 (LCD) on iOS 15.6.1 and found zero signs of flicker. I even tested at lower brightness levels and with a white screen and still found zero flicker at all. For the short time I used it, it seemed very comfy to look at. I may be buying one, haha.

                  • bz12 replied to this.

                    Brendan970 iPhone 11 is terrible for me on any iOS. It supposedly uses Temporal Dithering. Even the iPhone 8 Plus gives me issues, though it’s on iOS 16.

                      Having experienced that iOS devices cannot be downgraded to undo upgrades that introduced eye strain, and knowing how quickly an iOS device that deliberately is not upgraded anymore loses access to functional app updates, I believe in our situation the world of iOS devices is not the first place to look at. Ultimately it's your choice. I don't want to start a discussion, just dropping this here to think about.

                      Iphone 8plus is my daily driver, not perfect but still quite good to my eyes. Iphone 11 is unusable as it causes me severe nausea and fatigue, as the new ipads (have not tried the latest iPad 10.9 gen though)

                      10 days later

                      I recently bought an iPhone 11 and have been using it for a couple days, and my eyes are perfectly happy with it on iOS 16.2. Strange how some find it unusable while others don't. This will be my new daily for the foreseeable future. Feels just as fast as the S22 and iOS feels much better since the last time I had an iPhone, just wish it had more pixels.

                      On a side note, I have done some research in the interim, and found some interesting information regarding PWM in OLED phones. The frequency only seems to be part of the eye strain equation here, as the amplitude seems to matter lots as well. There are "relatively" cheap devices that can detect the amplitude of light flicker such as the Radex Lupin. This Russian channel tests lots of phones with the Lupin tool, with a higher number% being a more aggressive amplitude. the S22 ultra looks pretty bad, which explains why it gives me blood shot stingy eyes. The 11 Pro Max looks like one of the best OLED devices they have tested, alongside the OP 8 Pro. I have heard success stories with the 8 Pro's screen for sensitive folks.

                      Edit: Take a look at this thread on Macrumors.

                      dev