Many people here are suffering from flicker in various ways, and outside of this forum perhaps the most common symptom is to get headaches after a few hours of exposure. However, I noticed that when I'm exposed to triggering flicker (backlights, room lighting, ...) I get symptoms within just a few seconds. I further noticed that while the symptoms take a few seconds to kick in, the actual time necessary for them to be triggered can be very short. I am talking of a fraction of a second (the exact time I haven't experimentally measured yet). So basically, for me it goes like this: I look at flicker for only a fraction of a second. The symptoms begin to kick in, which takes a few seconds. Weird feeling around the eyes -> eye strain -> headache (in this order). The symptoms persist for multiple hours, disappearing over time. I am wondering if others have observed the same. Especially the very short time < 1 second that it takes to trigger the beginning of the symptoms.

Same for me, only takes an instant to trigger a migraine

My symptoms that can consist of tiredness, nausea or eye pain also usually kick in within a second or two depending on the device.

How many of you get symptoms from flicker within a fraction of a second?

Abeabe

For me light flicker causes faint spell sensation, tiredness, red eyes and eye pain, sometimes clogged ear sensation and neck strain, and the symptoms are worse if the flickering light is bright, the symptoms decrease a lot after I do exercise I think my problem is something related to blood circulation or something, something that doctors are not detecting or something they don't know about and I think the symptons are worse too when I am stressed or when I am tired.

photon78s

Abeabe

Actually, I'm reading about blood circulation and a medical/electrical concept called "zeta potential". Having poor zeta potential is indicative of circulation problems.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3576907/

That link is about how grounding/earthing might help with circulatory issues but make of it what you will.

I do think getting more circulation to the head and eyes is important. Also, I've heard raisins can help with ocular issues through polyphenolic nutrients as do deep breathing exercises, etc.

karut

For me the eye strain is also coming on this quickly, not leading to a headache.

AGI

KM Not sure if it is a fraction of a second, but definitely seconds for me, so it is not fatigue. Symptoms may persist for hours/days. Based on my very recent EEG results, I could tell you it is not photosensitive epilepsy either, if not that the flashing light of the test had a maximum frequency of only 20 Hz! I was recommended to take Lamotrigine nevertheless as the neurologist acknowledged that lights and displays affect my body.

ocean10

AGI

Interesting, I had started to wonder if maybe this was a form of epilepsy and was going to potentially explore that with a doctor.

Did the Lamotrigine work for you?

madmozg

It really depends, many screens gives different feelings, some of them instant, some after 10-15-30 mins.

ocean10

I'm similar to this. Things like OLED iPhones, modern OLED Android phones, certain monitors (not just OLED) give me symptoms immediately within seconds. Weird and uncomfortable sensation behind eyes, dizziness (but not like room spinning dizziness), foggy feeling, body warmth, sort of nausea feeling etc. It's a horribly uncomfortable feeling. LCD iPhones on later iOS versions also give me similar feelings but not exactly the same and maybe not quite as immediate. I don't seem to get the headache that many of the people here get but maybe I'm getting migraines just without the headache part. The symptoms take some time before they go away. Usually a few hours of gradually getting better.

For me I'm not entirely convinced it's pure flicker. As I've tried to figure this out I realize that many devices I've used for years have a TON of flicker and have never bothered me. And the LCD iPhones/iPads that were ruined after the iOS updates don't seem to have "flicker" in the same sense as something like PWM. I've also started getting symptoms from screens in many new cars. But I tested my current vehicles (a 2013 and a 2020) and realized that the interior lighting/dashboard and screens flicker like CRAZY. But I get no symptoms at all.

photon78s

ocean10

It seems many new cars interior and exterior lights have some sort of flicker. Been spending a lot of time trying to find or fix the right setup on this forum starting last year but from 2006 to 2013 when I was still using CRTs and an old laptop with TN PWM screen, I had no eyestrain issues. I have brought up EMFs and chemical smells (VOC, etc) in vehicles as contributors to symptoms but that is not the focus of this forum.

AGI

ocean10 For the moment I decided to not take any medication.

The epilepsy thing...I am not the only one on this forum who got tested. From my recollection, most people tested negative. Not sure what the frequency of the trigger was in their case, though. I feel like a high frequency test has not been conceived yet. I also have no idea if a sufferer of "classic" epilepsy, e.g., from stroboscopic lights etc, develops symptoms while watching a screen as well.

madmozg

photon78s I had BMW x3/x5 and now have ioniq 5. I don't have/had any problems driving those cars even with their crazy display or led interior lights PWM. I think its because i'm not focusing on display that much as when using laptop or phone screens.

photon78s

madmozg

Not to mention that your eyes are focused mostly on the road and distant objects and when you look at the screens you shift focus to near field. This shifting does not happen as much or not at all when one is staring at the phone or computer all day. Possibly other peripheral vision, blinking rate, and convergence and accommodation factors too.

From a brief test drive, I know some volvo xc90 heads-up display projection have significant flicker and that is always in your line of sight.

jordan

photon78s 2017 Cadillac Escalade and 2016 Corvette z06 both have wild flickery HUD too. Even interior control lights too but I don't think I am bothered by them like I would be on a screen

madmozg

photon78s agree. My 3 prev. cars all had heads up display, I had no issues fortunately.

ocean10

photon78s

I recently rented an Audi Q7 and a Land Rover Defender. In both cases the screens behind the steering wheel didn't seem too bad but the actual infotainment screens in the center gave me symptoms even if just in my periphery. Became very uncomfortable until I covered them with construction paper.

photon78s

jordan

Cool cars! I shall add that the different posture of sitting in the car and the physical and mental activity of driving itself might also affect eyestrain differently than in other contexts but this is just my hypothesis.

jordan

photon78s thanks! Unfortunately they aren't mine haha. I hope cars eventually eliminate bad pwm

photon78s

ocean10

That is really unfortunate and those are also high end vehicles. Hopefully you can at least access most needed functions without using the infotainment screens?

I think these developments may likely bring more issues from PC and phone arena to vehicles:

https://www.amd.com/en/solutions/automotive/in-vehicle-experience.html (amd radeon graphics powering car infotainment include video games for car displays)

https://nvidianews.nvidia.com/news/hyundai-motor-group-selects-nvidia-drive-infotainment-and-ai-platform-for-all-future-hyundai-kia-and-genesis-models

Would be interesting to know if current displays in cars are already FRC types but it looks like the trend will continue for more and more "immersive" displays.

ocean10

photon78s

I suspected the same thing. Was thinking that the dashboard screens behind the steering wheel potentially weren't using GPU's while the center console ones were. Might be an OLED vs. LCD issue as well since when an OLED screen is "bad" I seem to be more sensitive to it in my periphery than an LCD.

Every time I think I have this somewhat figured out something throws me for a loop. For example I originally thought for sure it had to be flicker that I was sensitive to. Still might be the case but it's definitely not ALL flicker. My 2020 Toyota Land Cruiser flickers like CRAZY everywhere (I'd post a video but doesn't seem to work, anyone know how to upload a video to Ledstrain?) But it also uses "old" technology since Toyota didn't update the infotainment in the Land Cruiser for many years.

photon78s

ocean10

I used dropbox link for my microscope pixel flicker videos and others use imgur. Thanks for another data point. I'll have to microscope and measure with oscilloscope some infotainment systems when I get the chance. You also have to consider the shape of the waveform of the flicker. Is it a gentle slope or abrupt and how random or not it looks. These all can cause different effects. I'm thinking as well their are more reasons than only PWM, temporal dithering, OLED dips, etc.

Ivan_P

Seagull I saw your other posts about adaptation to devices, and I was wondering if you concluded some devices to be acceptable for adaptation if they gave you immediate symptoms? Or did you choose only devices that gave you delayed symptoms?

Seagull

Ivan_P

Hi Ivan,

Most of the devices gave me immediate symptoms. I found I could adapt to those which gave me eye pain/conventional headaches, but I could not adapt to those which gave me migraines, immediate or not. However, my screen issues have improved massively since then and now I can also adapt to screens which give me migraines. My advice would be to experiment and see how it works for you.