hpst Incandescents, 100 Hz:
Osram 60W bulb: ~20% flicker
Osram 40W bulb: ~25% flicker
Osram 25W bulb: ~40% flicker
Unknown 40W candle bulb: ~40% flicker

All independent of the type of lamp they're put into. But whether I get symptoms or not from incandescents depends on the lamp. I don't know why yet. Some lamps I have are not usable.
Rough flicker estimates, because my PC died and I only have my handheld flicker meter currently.

Some more precise IKEA LED bulb measurements here: https://ledstrain.org/d/106-flicker-free-led-lights/81

I bought some flourescents, too, but can't test them currently without an x86 PC. The handheld flicker meter tells me there's lots of flicker going on with those at 100 Hz and also above 20 KHz. Also they are better for my eyes than the LED bulbs, but still not very comfortable.

Edit: Flourescent results:
Osram Dulux Stick 900lm: ~35% 100 Hz flicker + ~27% 60-80 kHz flicker

      KM It's all very confusing because in every possible class or factor I personally have an exception that prevents me from saying "LED is bad" or "CCFL is good" or "PWM is bad" etc. So I cannot accept ideas like "LED is 'harsher' and less smooth etc" as an explanation since some LED applicaitons are fine for me. I am desperately hoping that dithering is a solution on screens but that doesn't really apply to light bulbs so makes me less hopeful.

      • KM replied to this.

          hpst I agree it is very confusing. For the measurements I did a few minutes ago I got some eye strain symptoms from the 25W incandescent bulb. I looked into the light for only 10 seconds and now 20 minutes later still have strained eyes. When I put the same bulb into my ceiling lamp, no problems. There must be something I missed that has not been measured yet. But other than flicker or spectrum, I'm clueless. Matte or clear doesn't seem to matter here.
          My testing lamp is this: https://m.ikea.com/us/en/catalog/products/art/10394129/
          In fact all bulbs I ever tested in this lamp hurt more or less.
          Maybe for future measurements I should try to use the ceiling lamp, which I'd need to create a portable setup for.

          • AGI replied to this.

              AGI read some of you felt eyestrain after updating their browser. Question: could you ascertain the strain came only from the app which you updated?

              Yes absolutely - with the recent update to the Chrome browsers on PC. Gives me eye strain, as does the current Firefox. I rolled back Chrome to a previous version and everything feels "good" again.

              • AGI replied to this.
              • AGI likes this.

                  KM Maybe the lamp plays a role too?

                  • hpst replied to this.

                      AGI If I wasn't physically disabled to the point I couldn't survive there, I'd move to a cabin on a beach with fire and books. It seems technology is out to kill us when even a lamp is suspect.

                        AgentX20 Thanks. I actually just asked this question in another thread. Did you experience eyestrain only in the window of the browser? No problem using another program?

                            AGI Did you experience eyestrain only in the window of the browser? No problem using another program?

                            With the 'bad' Chrome/Firefox window on screen I got eye-strain. Close it, and everything was fine.

                                7 days later

                                tfouto The link doesnt work.

                                I had another meeting with my optometrist. He told me that basically with my kind of deviation from normal vision, hes suprised the new displays is the only thing causing me trouble, as it should show in all areas of my life. I have 20 points deviation out of possible 12. He said I should maybe be thankful that I started having these issues, as otherwise it would go unnoticed and develop into a lot worse case of possible visible strabismus or diplopia in couple years.
                                I explained to him the idea behind dithering and he said it makes a lot of sense for it to be really disturbing, and that the therapy should hopefully fix it. Hes also willing to dive more into research when hes more free and said that it would be amazing if we found a specific proof of it (dithering etc), as it could make a good article. Also different polarization than in the past could be the cause.
                                He also mentioned a lot of optometrists, even those he is schooling, do not believe in heterophoria (hidden strabismus), they think its psychological often and that it is really difficult to get proper care for it. He mentioned the best center in the USA being in New York, I think some people already posted a link to health thread.

                                Ive been given new exercises, which can now be done without a computer and are composed of a translucent board with images I try to connect by converging and diverging. I must say that the divergence, which is my problem, is really difficult, takes forever to fuse the images and then theyre not sharp, sharpness kicks in after another 10 seconds, if anything moves in the field, its lost again. This would explain how dithering/flicker/movement is giving me trouble on the displays. Even trying it with the board properly (no display involved) I soon got the very familiar stabbing pain in the temples and all over the head. I gave it to a person who has no issues with displays and he could connect all of the images effortlessly in an instant.

                                I really recommend, if you can, trying to find proper care, as it might be what we all have in common. Id love to beat the marketing and display manufacturers, but now even software employing weird rendering, I dont know how, as whenever I win, they come with more, so Id rather build resitance instead. Hopefully that will happen.

                                    martin Blue filter amblyopia treatment protocol for strabismic amblyopia: a prospective comparative study of 50 cases.
                                    Metzler U1, Ham O, Flores V, Claramunt M, Sepulveda C, Casanova D.
                                    Author information
                                    Abstract
                                    PURPOSE:
                                    Previous studies of monochromatic visual evoked potentials confirm the strong suppression of (the cortical representation of) paracentral retinal areas of functionally amblyopic eyes, by a flat response to a blue stimulus. A clinical trial stimulating these areas with blue light was encouraging, and justified a prospective comparison of this treatment with conventional classic treatment.

                                    SUBJECTS AND METHODS:
                                    In 50 strabismic children with amblyopia, the blue filter treatment protocol (flash stimulation with, and the wearing of, a blue filter during occlusion of the better eye for one hour daily) was compared with the classical treatment (full time total occlusion by patch) in a prospective matched and randomized study. Patients 3 to 7 years old without previous treatment and a visual acuity up to 0.3 were admitted to the study. Visual acuity and fixation behavior were used as the parameters of comparison. Visual Evoked Potentials by monochromatic flashes were also studied. Results of treatment were compared after 6 months.

                                    RESULTS:
                                    The visual acuity outcome for the blue filter treatment was "statistically significantly" better (p=0.005). The greatest improvement was seen in the subgroup of children with eccentric fixation (p=0.01). Fixation behavior also showed a better outcome from the blue filter treatment (p=0.05) favoring especially children between 3 and 5 years. In children of this age with a visual acuity better than 0.1 we found a very "statistically significant" difference between the two treatments (p=0.004). In children 3 to 5 years old with poorer visual acuity we also found a "statistically significant" difference in the two treatments (p=0.04). The interocular difference of amplitude on the Visual Evoked Potentials also demonstrated more improvement in children treated with the blue filter. This treatment improved especially the cortical response to blue flash stimulation, correlating to paracentral retinal areas.

                                    CONCLUSIONS:
                                    The blue filter treatment protocol provided better results for treating amblyopia than the conventional classic occlusion treatment method. We propose that stimulation of these paracentral retinal areas triggers a better disinhibition of a functionally amblyopic eye.

                                      tfouto No, I have no idea what Im sensitive to. Id guess, given my faulty eye teaming, anything that can disturb it - pwm, blue light, flicker, dither, glare...? If I knew Id know a technical solution. I dont, so Im attempting health solution.

                                        martin He mentioned the best center in the USA being in New York, I think some people already posted a link to health thread.

                                        Visited the center today. Not sure if it's the same one, if you could get a specific place, I'd greatly appreciate it. I would love to see them.

                                        I was told I have definite eye teaming and focusing issues and very bad depth perception and peripheral vision and suggested vision therapy. He couldn't term a specific diagnosis, but that coverence insufficiency is the closest one.

                                        The vision therapy out of pocket will cost a several thousand USD. I am still trying to see if my insurance will pay for some of it. Out of pocket I'm hesitant to pay for it in total unless I knew it'd fix the issue. But, I don't think there's any harm other then cost and time.

                                        Using my new LG G7 gives me these strange muscle twitches and noise sensitivity. Makes me think it's neurological or nerveous system related. The optometrist told me he thinks my nerveos system is very sensitive based on pupil dilation. He said different colors of light have a great affect on the nerveous system and showed how my muscle strength actually weakened when these light colors came on. I wonder if this phone is emitting some color of light that I'm sensitive to.

                                        He also said my eyes were very slow to focus, something you also seem to take a long time with (mine was several seconds, but not quite 10).

                                        I'm considering trying a different behavioral optometrist to see if they come to the same conclusion that VT is helpful.

                                        Glad to hear about your updates though and love the progress. I really hope this fixes your problem. Please keep them up!!

                                            ryans Amazing to hear that you have some sort of diagnosis and that it fits with the general theory. Really sad to hear how much that costs. Maybe it would pay off for you to take a trip to europe and get the care here, although I dont know how possible it is. When my therapy is finished, including two sets of glasses, It wont cost me more than 600 dollars in total over the 6 months. The prices in usa are outrageous.

                                              ryans I wish I could find such a doctor here.

                                                  ryans Maybe hold off on any expensive therapies until you can evaluate the efficacy. I have done VT before, and I do maintenance exercises at home twice a week which don't cost me anything. Of course it helps that I've been through the training before and I know how to do the exercises. You can always try strengthening your convergence with simple pencil pushups.

                                                  These exercises will only help for the issue that your eyes eventually get tired after a long session of computer use, or if you're doing a lot of intense work like in Excel or reading a bunch of email all day.

                                                  However, it won't help for the issue where your eyes/brain instantly ache upon looking at the display within seconds/minutes. This happens to me on LED-backlit monitors, and I have not found a solution yet unfortunately. Avoidance is the only recommendation I have in that case. Here's hoping that my Dell U2410 lives a long life!

                                                      JTL I can ask if he knows anyone in BC area. I suspect there's definitely some in Seattle area at the very least. If I didn't live with my folks, I'd let you stay at my place to get a diagnosis and treatment, but the commute is kind of far.

                                                      • JTL replied to this.

                                                          MagnuM However, it won't help for the issue where your eyes/brain instantly ache upon looking at the display within seconds/minutes

                                                          Yeah I'm very skeptical it will help me with neurological or nervous system related issues.

                                                            dev