People in this forum describe many different factors that affect whether eye strain occurs. However they usually fail to isolate one main factor which decides about it, because this depends on many different factors that affect each other. Monitor, computer, GPU, operating system and even HDMI cable affect whether there is eye strain or not. The fact that eye strain occurs depends on all factors taken together and how they affect each other. You can not find a monitor or a computer that will ensure no eye strain.

Often a monitor works well with one computer and the same monitor works badly with another computer. And vice versa often one monitor causes eye strain and another not even if they are connected to the same computer. So you cannot say that the cause is only monitor or only computer. Sometimes even HDMI cable used for connection decides whether eye strain will occur. Furthermore, often eye strain occurs only when using certain operating system or driver and does not occur while using another operating system (even if computer and monitor are the same).

People say that if they use this "bad" operating system in a virtual machine or via VNC, their eye strain does not occur. So the cause in this case are not colors/animations/fonts/pixels displayed by the operating system. The reason is also not temporal dithering, because even if it is turned off (and it was tested that it is actually turned off), the "bad" operating system still causes eye strain when running as host system and does not cause eye strain when running in virtual machine. So in this case eye strain is not caused by pixels (image) displayed by a given system, but it must be caused by something else.

Here are some interesting and surprising cases that affect eye strain:

HDMI cable: https://ledstrain.org/d/214-hdmi-vs-vga-cable-and-eyestrain/

Power supply: https://ledstrain.org/d/1106-intel-hd-graphics-eyestrain-and-using-laptop-without-power-supply-as-solution

Partitioning scheme: https://ledstrain.org/d/1087-i-am-using-linux-comfortably/15

Based on posts on this forum, I suspect that a very important factor affecting eye strain is electromagnetic interference (EMI). Electromagnetic interference can obviously cause flickering of backlight or pixel (they will dim and brighten with the frequency of interference). Electromagnetic interference is transmitted through air only for very close distance (because power falls very quickly), but it is also very well transmitted through each metal wire for long distance (even if that wire is not connected to anything and simply lies nearby). Even if the HDMI cable uses digital signal that transmit data without losses, the electromagnetic interference noise is still transmitted by this cable from computer to monitor and from monitor to computer. Thus high frequency electromagnetic noise generated by a new processor or GPU or SSD drive is transmitted through HDMI cable to the monitor. Even if the monitor would be wireless or connected via optical fiber (but such technologies probably do not exist), the electromagnetic noise still would be transmitted through electrical network in the building.

Once I observed an interesting phenomenon. When I connected a 5V power supply to an electric socket, my monitor began to flicker (it was not eye strain, but a very strong flickering that was clearly visible to every person). This happened even if this 5V power supply was connected far from the monitor in a completely different room. After disconnecting the power supply, the monitor stopped flickering immediately. The only logical explanation in this case is "dirty electricity" (harmonics and transients generated primarily by electronic devices and by non-linear loads) transmitted through the electric network in the building. So even if my neighbor in his apartment connected that power supply to the electric network, the monitor in my apartment would probably be flickering.

Therefore, I suppose that electromagnetic interference is really important factor influencing eye strain. Computer (CPU, GPU, hard drive, etc), monitor and operating system affect which frequencies of electromagnetic interference are generated. Different monitors can be affected differently by different electromagnetic noise frequencies (for example LED could be affected differently than CCFL) hence the difference in symptoms on different devices.

An easy way to hear low frequency electromagnetic interference is AM radio. Just put the radio near computer, monitor or HDMI cable. In this very simplified way, you can compare noise generated by different hardware and software.

What do you think about it? Maybe connecting monitor or computer to double-conversion UPS (which filters dirty electricity) would sometimes help?

  • mike replied to this.

    Simple check: if there's no strain when person turns away from the screen but stays within the same distance from electromagnetic source, it is not electromagnetic interference.
    Anyone can sit behind the screen and check.
    In my case it is not. I suffer from phones, if turn the screen off with all the wifi, mobile networks etc. actively working, or turn the screen away, everything is ok. I can even put the phone next to my head, to talk, an everything would be ok.

      matix

      Hi matix, and welcome to LEDStrain!

      First of all, it would be nice if you write about your eyestrain problems.

      I have had this eyestrain problem for 10 years. Under that time i have ran into many situations. I remember back in 2014 when i upgraded iOS on my iPhone 4S. Before i could use it for an hour without any problems. After the update, if I used it for 30 seconds my eyes was hurting so much. A few months later Apple released a iOS update and i could use it again. It wasn’t only me who had this problem, I found some more users on the Apple forum with the same problem.

      If you read more on this forum you realize that people nowadays use notebooks and phones, some works, and some not. If you update some software/firmware and so on, something can change. I remember some years ago when I updated Chrome on my old computer and got eye strain, and i was not the only one.

      Some users have connected their computer with a cable that send less information to a external screen. VGA instead of HDMI, and it have worked better on some computers. This can be a workaround, but that is not the problem here, it’s dithering and similar techniques.

      matix Often a monitor works well with one computer and the same monitor works badly with another computer.

      I would say that’s wrong.

      matix Sometimes even HDMI cable used for connection decides whether eye strain will occur.

      If the cable is broken!?

      matix Furthermore, often eye strain occurs only when using certain operating system or driver and does not occur while using another operating system (even if computer and monitor are the same).

      Dithering and similar tech.

      matix People say that if they use this "bad" operating system in a virtual machine or via VNC, their eye strain does not occur.

      I would say that it’s the other way around.

      matix The reason is also not temporal dithering, because even if it is turned off (and it was tested that it is actually turned off), the "bad" operating system still causes eye strain when running as host system and does not cause eye strain when running in virtual machine.

      How did you turn it off? I really want a answer to that question! And their is more techniques with rendering, so you can’t know that for sure.

      //Mike from Sweden

                    People say that if they use this "bad" operating system in a virtual machine or via VNC, their eye strain does not occur. So the cause in this case are not colors/animations/fonts/pixels displayed by the operating system. The reason is also not temporal dithering, because even if it is turned off (and it was tested that it is actually turned off), the "bad" operating system still causes eye strain when running as host system and does not cause eye strain when running in virtual machine. So in this case eye strain is not caused by pixels (image) displayed by a given system, but it must be caused by something else.People say that if they use this "bad" operating system in a virtual machine or via VNC, their eye strain does not occur. So the cause in this case are not colors/animations/fonts/pixels displayed by the operating system. The reason is also not temporal dithering, because even if it is turned off (and it was tested that it is actually turned off), the "bad" operating system still causes eye strain when running as host system and does not cause eye strain when running in virtual machine. So in this case eye strain is not caused by pixels (image) displayed by a given system, but it must be caused by something else.

                    This is for example not true for me. I still have problems with VM or remote Desktops depending on resolution/framerate/fonts/animations/colors etc which I for example don't have with one eye closed or if other software related factors change.

                      Mrak0020 Simple check: if there's no strain when person turns away from the screen but stays within the same distance from electromagnetic source, it is not electromagnetic interference.

                      Hi!

                      You probably did not understand my post or I did not write it clearly.

                      I do not suggest that EMI directly affects the human body (although maybe it is also possible for some people - I don't know). I suggested that EMI may affect the monitor and cause flickering or other noise - as I explained in the real life example.

                      Your simple check is good at the beginning. However it is not perfect. It will not exclude the possibility that only the combination of two factors (EMI plus light from the monitor) causes eye strain. But I think that it is more likely that EMI simply affects the monitor and in turn the affected light from the monitor causes eye strain.

                      mike First of all, it would be nice if you write about your eyestrain problems.

                      Hi!

                      I have not yet understood my eye problems. My symptoms are not so clear and not so strong as other people have. I do not feel eye pain. My eye symptoms do not appear immediately. But looking at monitors and any other light sources (except sunlight) is unpleasant and tiring for me. If I use a new notebook for a longer time (a few days or weeks), I fell tired/exhausted and I have brain fog, concentration problems, attention problems, memory loss and forehead pain (symptoms that appear when brain is exhausted - similar as in ME/CFS), but I don't have direct and strong eye pain as other people in this forum. Instead if I use my old CCFL monitor (connected to the same new notebook), I feel that I am much less tired and much less exhausted and I have much more energy. But my symptoms does not change immediately after changing the hardware. I can easily use bad hardware without any symptoms and only after a few days it turns out that I'm exhausted. And regeneration also takes several days.

                      Because my symptoms do not appear immediately and are not so strong and distinct, I am not able to easily compare hardware (and evaluate which is bad and which is good). That's why I try to understand what causes the problem to choose the equipment that will cause as little fatigue as possible.

                      mike If the cable is broken!?

                      I do not have such problem with HDMI cable. I wrote it on the basis of what I read in the "HDMI vs. VGA cable and eyestrain" topic in this forum.

                      mike How did you turn it off? I really want a answer to that question! And their is more techniques with rendering, so you can’t know that for sure.

                      I don't know for sure. I wrote this also on the basis of what I read in this forum. Other people performed test for dithering using external HDMI recorder. There is for example "Temporal Dithering Testing" topic in this forum. Maybe testing was not performed correctly, but I don't know.

                      xelaos This is for example not true for me. I still have problems with VM or remote Desktops depending on resolution/framerate/fonts/animations/colors etc which I for example don't have with one eye closed or if other software related factors change.

                      I understand. Probably there are many different causes which gives the same symptoms (eye strain, etc). But I remember that someone wrote that he can use linux in virtual machine without any problem and he can't use it when running as host operating system.

                                  matix I suggested that EMI may affect the monitor and cause flickering or other noise - as I explained in the real life example

                                  Oh I see. You're right. Sorry, my mistake. Totally missed the point.

                                  You might be interested also in checking out the insides of a screen. This is what I am doing right now. I have a few ips screens and looking trough the layers. (Amoleds most definitely do same effects with light, using different set of tools, so I will leave them for now). Every IPS layer, or every LCD layer, makes some impact to the characteristics of light. When I look at those layers in my hands, they are like glitter over glitter over mirror over glitter, so I suppose flicker might be not the source of a problem, but some signifier of a things within the screen. As layers are flickery by themselves, when the screen is teared down.

                                  (If you have never seen them before, you can search teardown (screen type) or what's inside (screen type), but all the glitter and flickering are hard to see through the camera. Layers have very interesting optical qualities)

                                  matix I can easily use bad hardware without any symptoms and only after a few days it turns out that I'm exhausted. And regeneration also takes several days.

                                  Your symptoms are unusual, but the timing is not; I've seen other people who need time to go both directions, to accumulate damage and than to heal.

                                  Do I understand correctly that you have no clues at all if your cause is hardware or software?

                                        Mrak0020 Do I understand correctly that you have no clues at all if your cause is hardware or software?

                                        Yes, I'm still not sure if all these symptoms are caused by my eyes. I have carried out too few tests yet, because my symptoms are not so clear and not so unambiguous and start with delay.

                                        But I'm sure that all artificial light sources (except sunlight) are much more unpleasant for me than for my friends. This is the most severe if the light source is in my field of view (especially at the bottom of my eyes). All diodes are very unpleasant for me (for example diode signaling that a monitor is powered up) so I often cover them using insulating tape.

                                        I also remember that my eye problems and other symptoms stared about 8 years ago when I started using new notebook. Ophthalmologist only said that it is dry eye syndrome in those days. I've never had any problems with my eyes before.

                                        I also have a feeling that using my old CCFL monitor is less tiring for my eyes. However it is still uncomfortable and I set brightness and contrast to very low levels (much lower than my friends) and it helps significantly. I would like to find a monitor that will be less tiring for my eyes. And also I would like to find lightning that is less tiring for my eyes. I use traditional incandescent bulbs, but sometimes (not always) I can even see as they flicker with naked eye (probably when there is higher noise in electrical network).

                                        Maybe I have much milder form of eye strain so I do not notice symptoms immediately but fatigue accumulates.

                                            matix
                                            I understand you so much with the dry eye part. I faced some sort of the mild eyestrain many years ago, got all the same responses. I could not connect it with tech, it was way milder. Probably influence came much later after the purchase, similar to your case. I believe now it was connected to some tech. It disappeared in few months.
                                            I faced a severe eyestrain this year, realized I have an eyestrain with every modern smartphone. Since that realization I've done an infinite amount of tests. They definitely cost me some eye health, but I hope that is temporary. Your situation seems complicated. Do you have any save tech right now to at least let your eyes heal after bad tech and tests?
                                            It is hard to tell what affects eyes in all the different stories people have here. Sources may be different, from flickers to leds.
                                            But mechanics seems to be similar: something within the light or within the image affects eyes and they respond heavily, presumably damaging themselves.
                                            I wonder what happened first: you purchased that notebook and later noticed a problem with light sources, or vice versa?
                                            I saw couple of reports that low contrast help - with the exact problem I am facing - on some devices, but not all.

                                                Mrak0020 Do you have any save tech right now to at least let your eyes heal after bad tech and tests?

                                                Unlike others, I can't explicitly determine whether a hardware is good or bad. I feel that my old CCFL monitor is better than any notebook screen which I tested. But I feel that it still is not perfect. I currently use this old monitor connected to my new notebook through HDMI-VGA adapter.

                                                In the past I used this CCFL monitor with my very old desktop computer and it didn't cause any discomfort. Back then I was also not sensitive to any artificial lighting. Incandescent bulbs, fluorescent lamps and diodes did not cause any discomfort - I had perfectly healthy eyes.

                                                Mrak0020 I wonder what happened first: you purchased that notebook and later noticed a problem with light sources, or vice versa?

                                                I noticed the problem with eyes about 3 months after I started using new notebook (but I don't remember exactly). My first symptom was that I had to set very low brightness on the notebook screen. I remember that once my friend (we were doing something together on my notebook) asked me to increase brightness. I replied that I can't because my eyes hurt on greater brightness. He was puzzled because the brightness was very low. I started noticing photophobia (light sensitivity) several years later. But sunlight still does not cause discomfort for me. Also sometimes I don't have discomfort in places where there is romantic lighting - many low-brightness lamps which evenly and dimly illuminate the room. Discomfort is the least if I don't see the source of light directly (the lamps directed to the ceiling and covered).

                                                Back then I did not connect my problems with changing computer because symptoms did not start immediately and on low brightness I had no discomfort. So i was just using low brightness and I accustomed to it. Also I did not change computer immediately - for a certain period, I used both computers.

                                                I am still not sure if the notebook was the cause of my eye problems. I remember that I started using energy-efficient lighting (fluorescent lamp) in my home about 7-11 years ago (I don't remember exactly when) for the first time in my life. I suspect that it could also affect my eyes. Before that I always used only incandescent bulbs in my home.

                                                Mrak0020 I saw couple of reports that low contrast help - with the exact problem I am facing - on some devices, but not all.

                                                Reducing the contrast on my monitor simply reduces the brightness. That's why it helps me.

                                                      Yet another "Source of problem".

                                                      Just tested 2 4k displays and both caused severe eye strain after one workday use. Now I was finally able to connect my offending laptop with a USB-C -> DisplayPort adapter to my old HP ZR2740w display, which I have used for 10 years without any strain with all windows and linux versions and different display adapters. (Currently Geforce 970).

                                                      Now I can confirm that it does not cause eye strain even when I'm using my Lenovo laptop connected that does cause eye strain. So for me it is not the display adapter or driver or windows version.

                                                      IT IS the panel technology.

                                                      Now we would need to find out what is it in the panel technology that is causing eye strain for many people.

                                                      I have tried Ditgerig.exe, with several laptops, with admin rights, but I have not found it to be helpful at all. But I cannot be sure if it really did anything for the temporal dithering.

                                                      But having tested dozens of laptops and displays and phones over the years, there are LCD screens without PWM that do absolutely not cause any strain. I can rest my eyes that are irritated from PWM or bad LCD with my Moto 100g or HPZR2740w display.

                                                      dev