I looked with a spectrometer at ceiling lighting at work. It is mostly fluorescent lamps. The one that bothers me like crazy seems to emit warmer light as perceived by the naked eye. I asked colleagues for their opinion and, although I am the only one to be affected - what a luck! -, we all agreed. The incriminated lamps are definitely softer than the bright fluorescent ones in the labs. Strange, I thought, because I would expect the warmer, the lesser blue radiation, and the easier on the eyes. Then I measured the spectra and surprisingly found no difference. Bad (softer) and good (brighter) lamps are spectrally the same. Please do not compare intensities spectrum to spectrum, as I just held the fiber in front of each lamp without using the same distance and the same tilt (relative intensities within each spectrum are instead correct as the spectrometer is calibrated from ~ 320 to ~ 740 nm). Zoom-in There are quite sharp lines at ~ 405 and ~ 365 nm. That is in the middle of violet and at the beginning of UV-A, respectively. Sounds bad, but also the good lights have such peaks. Also, using blue light-blocking goggles does not really make a big difference (light can come in from the top though). Wondering what is the reason behind my immediate eyestrain and twitching when I get under the bad fluorescent lamp, the only thing that comes into my mind after those measurements is that it is not warmer versus colder but rather lower versus higher wattage. Can lower wattage imply an accentuation of the flicker? Unfortunately, I cannot probe for shorter than 10 ms, so I cannot see above 100 Hz. I believe the spectrometer itself is capable of much better, and data-transfer to the pc is the limiting factor. I glanced on frequencies of fluorescent lamps mounting an electronic ballast and they seem to be really high though, above 10 kHz, so I am skeptic I can be sensitive to that either. Also, I read such lamps start within half a second without flickering. I'd better ask someone from the facility department. The LED lamp (black solid curve) is also "bad". There is quite some intensity at the border between violet and blue, but I am not sure that is why it is harsh on my eyes. Maybe it is flickering in this case too? Finally, I turned the "bad" fluorescent lamp off. I can still see "bad" fluorescent light from other lamps of the same type in the office (red dashed curve below). The closer to the one turned off is about 1.5 meter away from my desk. I have been checking if blending the bad light from the other bad lamps in the room with two desk lamps with incandescent bulbs helps (green and blue curves below), but it is very difficult to make an assessment. My eyes do not recover from strain like an on-off switch, unfortunately. And by the way, in a few days my colleague sitting under the bad lamp will return and I will have to turn it on again. Useless to say that my eyes feels the best if I turn towards the window and get some natural light (blut curve). On the weekend I was in a modern hotel with only LED headlamps. It was dreadful. I am really scared about what is coming next.

Is electromagnetic hypersensitivity real?

Overhead lighting

AGI

deepflame Hmm, and I assume the "bad fluorescent" line matches the ones of the good one? If so, this is really strange indeed. Maybe some flickering then?

That is right, and that is what frustrates me.
I do not get how I can perceive warmer light if the spectrum is the same. I got the doubt the paint of the walls and the furniture, which are all brownish/reddish, plays a role, but I asked other people, and they confirmed the light is softer in the office than in labs. I guess it is supposed to be more relaxing. Not for me. You should see, after a minute at work on Monday my eyelids start twitching like crazy.

I was unable to measure the frequency. I am speculating that the bad lamp outputs lower power light with the same spectrum of the "good" lamp, and at lower power the radiation flickers more, a bit like for PWM-controlled displays if the brightness is lowered the switching on and off of the back-lights becomes more frequent.

deepflame

AGI This is one of the weirdest things I have heard so far. I mean CCFL backlit screens for example tend to be better than LED screens as well.

Maybe there are other light sources than the fluorescent tubes that cause the twitching? Maybe even the screen itself?
Thanks for sharing this...

krr55

AGI

I have checked my home lights and TV's using this application for Iphone. It is not 100% accurate but at least it is helped me to understand why my Samsung TV, Iphone XS and some LED bulbs are giving me severe eyestrain. Have tried to find similar other free app with no success.

Spectrometers are too expensive to buy (Above 1K USD). So other acceptable way to measure PWM with 10-20% accuracy for me was to purchase this device this Radex Lupin. It can be connected to laptop and show some graphs at least.

If you guys know any other acceptable ways to measure PWM flickering let us know.

AGI

deepflame This is one of the weirdest things I have heard so far. I mean CCFL backlit screens for example tend to be better than LED screens as well.

My analogy to PWM-driven control of the brightness is likely incorrect. I read a bit about electronic ballasts and thought that at low power they may behave in a way my eyes/brain are hypersensitive to. But, as I said, the fluorescent lights in my kitchen and living room visibly flicker and are blue-shifted. No pain.
I am confused. Can high frequency flicker bother more than visible one?

deepflame Maybe there are other light sources

For sure, my iMac is not smooth on my eyes. I can use my MacBook Air fine at home and not at work, though. I have problems just standing under those lamps, or reading on paper. But, yeah, ruling out variables is hard because my symptoms are long-lasting.

deepflame

AGI I see, wish you all the best with everything

AGI

deepflame Hmm, are you sure these are fluorescent lamps? I have seen mostly LED tubes recently here in Germany. Not sure if they sell normal fluorescent tubes anymore.

Hey, I thought of sharing additional details I got, in case you and/or someone else is interested.
All the lamps I tested, "good" and "bad", are of exactly the same type (Panasonic FHF32EXLH), which explains why with the spectrometer I did not detect spectral differences.
The light color is called "electric bulb" (there are eventually other variants with different colors, e.g., natural, white, etc. etc., which are not installed anywhere at work, as far as I know).
https://global.rakuten.com/en/store/denkyu/item/n048hf32exlh/

From another document - which is only in Japanese - I see (ehm, I guess) that the color temperature is 3000K.

Looking more deeply at the specs I infer that there are either two subtypes of FHF32EXLH lamps or the same tube can be run two ways, low and high power, namely, 32W / 0.255 A / 3520 lm / 3000 K and 45W / 0.425 A / 4950 lm / 3000 K, respectively. Note that the color temperature is the same.
The facility people who take care of the lighting confirmed the lamps in the office ("bad') are dimmer than the ones in the labs ("good"). Hence I conclude that the "good" lamps are the high power ones, and the "bad" lamps the low power ones. Color temperature is the same (--> same wavelengths in my spectra), and is very low so there should not be much blue light. Then what can the trigger of my eyelid twitching and eyestrain and migraines be? I do not see any plausible reason why a small luminous flux triggers symptoms and a larger flux of the same spectrum does not. I can only think that running the tube low power causes more (imperceptible to most) flickering.

Any thought is greatly appreciated!

KM

AGI Did you measure the flicker yet, to see if there's a difference between the lamps?

AGI

KM No, I have not been able to but it is on my agenda (if I find the right equipment).
I really want to understand what I am sensitive to, besides the short-term goal of putting an end to this suffering.

From the last email I received, it seems the tube can be changed but the new type will still run at low power, so I assume there are not two sub-types of tube for each color temperature, but one type which can be run two ways. In the office though, only the low power mode appears possible. I guess it depends on the circuitry?

Another thing I was written, which is unclear to me, is

The power voltage for those lights is 100V and the frequency is all 60MHz.

60MHz? What is that frequency? How does the flicker frequency relate to it?

AGI

KM Did you measure the flicker yet, to see if there's a difference between the lamps?

I am not sure I did things right, and I had to return the equipment so I have not been able to compare "good" and "bad" lamps yet, but here is a preliminary measurement of the flicker of a "bad" fluorescent light.
100 KHz....sounds high to be sensitive to, does not it?

KM

AGI 60MHz? What is that frequency? How does the flicker frequency relate to it?

That's probably the frequency at which the tubes are driven, but I don't think it means there's no other low frequency flicker. I read such tubes can be driven at up to 200 MHz.

AGI

@Slacor 🙏

AGI

On my request, I got the fluorescent bulb closest to my desk changed from 3000 to 5000 K. At the moment of the swap, eyelid twitching was bothering me little and seldom, not sure if my eyes had adjusted a bit to the light or if other co-factors played a role, like diet or slightly better sleep. Note, I still badly suffered from eyestrain and poor concentration / performance.
At the change of the bulb, I found using my MacBook Air and my iMac was a bit more pleasant, however, at the same time I felt my eyes got more fatigued (I know it sounds a contradiction, but that is how I felt). Well, after three days under the new bulb, eyelid twitching returned, and way stronger. The weird thing is that it now affects almost exclusively the right eye, whereas earlier only the left eyelid twitched! At times it is so persistent, that I can not even work. I sometimes have twitching also outside the office, especially when I change my direction of view and when I am talking to people. But it gets really intense when I sit under the bulb. I wish I had some kind of meter to prove that. The onset of the twitching clearly coincided with the change of the bulb, apart from an incubation time of 2-3 days.

I was not expecting much from a change of the color of the light to be honest. I remind you that the same 3000 K bulbs are okay in the neighboring labs, where they run at higher power (I have not tested a 5000 K bulb at high power). So for some reason lower power makes the lamp bad for my eyes, whatever the color temperature.

Sunspark

AGI Eyelid twitching is a psychological stress reaction.

AGI

KM Yes, it is similar to when I look at a bad device. Short exposure causes damage, and the damage does not fade quickly upon removing the trigger.
I do indeed feel enormous tension in my face muscles. I never experienced this before, it had always been more of a neck and back of the head tension, accompanied by eyestrain. In the past though I was always able to dodge bad devices and I was never subjected to such discomforting lighting conditions for long. My twitching did not start immediately. It took about 8-9 months. Initially I only suffered from eyestrain and poor performance at the computer and also reading on paper. You may also remember the story with my Samsung Galaxy on5. I now have doubts that the phone became "bad". It may be that I have subjected myself to unbearable conditions for too long (lighting and two Macs), and at a certain point my body started sending out warnings like twitching and photosensitivity.

Sunspark Eyelid twitching is a psychological stress reaction.

I tend to exclude pure psychological effects, if what you mean is that for instance I am stressed out at work and / or do not like my work environment etc. etc. It is not really the case. I am surviving right because I do not have much pressure. But I am unhappy and worried about my state, so that could psychologically influence.
I am more inclined to think that I have been killing myself for nearly 2 years under horrible conditions, and my body is worn out. I think eye and face muscles are similar to other muscles. If you over-stimulate them and if they are not fit (I do not exclude I have some underlying eye condition like heterophoria), they will let you know sooner or later.

@KM Have you explored the psychosomatic avenue?

Partial good news of the last < 24 hours. There has been a rotation of people and a row of LED spotlights which we used to keep off has now been turned on by the newcomer. I freaked out but interestingly working at the desk feels a bit more pleasant. I hope I can confirm. And if it is the case I will try to run some tests and dig out light specs.

KM

Does the light make your eyes irritated and then the feeling stays for hours? Happens to me. Happened an hour ago with my backyard lights. Just a few seconds of exposure and my eyes and surrounding face muscles (cheeks) feel like they've been through a marathon, which can persist for hours.

KM

AGI Have you explored the psychosomatic avenue?

No, not yet. I still refuse to believe in this. The symptoms are 100% reproducible, with different results for different lights. There must be a medical explanation other than "it's all in your head". Plus I suffer from PWM, driver eye strain, pretty much all the main problems that have been discussed here. So we all have similar symptoms and the reason for that cannot possibly be we all had the very same psychosomatic problem. Makes no sense, doesn't seem likely at all.

Peter

From my perspective it seems there is a disagreement of our brain to the displays / light we look at. The stimulus (light/display) creates a specific response which may be similar to the stress response, but it is the device or light that creates this.
After some years of training in somatics i can quickly reverse any of the symptoms i get from any device, however this cannot be a permanent solution to engage every 20 mins in 10 mins of release activities to reduce the tension in my body.
So for me this is definitely a tech issue and there is a very clear and distinct stimulus. The new displays/lights create all kinds of tensions in the head and upper body starting with the eyes. Also the eyes initiate and control most motor behavior so it is normal for tension to appear in various forms in the head and upper body (eg headaches, neck/jaw, etc).

AGI

Peter After some years of training in somatics i can quickly reverse any of the symptoms i get from any device

Interesting. I know nothing of somatics. Is it some kind of exercise involving controlled breathing?
Do you suffer from instantaneous severe symptoms in front of "bad" devices?
Do you mean that, if you did not have to use the bad device anymore, after practicing some exercises for a few minutes you would be fine and free from symptoms for the rest of the day?

Peter

AGI Somatics is the genre for some body training methods like the Alexander Technique, Feldenkrais, Pilates, etc. Personally I am studying the Alexander Technique for about 5 years due to a back problem.

I can actually get back to almost symptoms-free in less than 30 mins. After two or three hours i am like i never used the bad device. And yes i do get instantaneous severe symptoms if i use a bad device.
However learning any somatics techniques takes time.

My Alexander teacher believes that if my eyes become more flexible in their movement i will be able to adapt. We are working specifically on this for a couple of months now, however i still cant say i have seen significant progress but i know it takes time to alter long standing muscular habits.

AGI

Peter i know it takes time to alter long standing muscular habits.

Thanks for sharing.
So it has to do with muscles. It is not a psychological issue, at least in the first place. That was my thought too, without being an expert in the field.

AGI

Seagull Probably comes down to how they are powered. If the LEDs are powered by a standard light bulb fitting that will take any type of bulb they will flicker. But, if they are driven by some purpose built LED power supply, with a proper AC-DC rectifier, they will not flicker.

Moved from My treatment progress and search for solutions

Interesting! Would that apply to fluorescent bulbs as well? Summarizing the thread I had opened and forgetting for a moment about the LEDs, I got rooms with fluorescent bulbs run at low power which drive me insane and other rooms where the same model of bulbs are run at higher power and give me no issues. I was changed the bulb color temperature in the office but the power could not be varied, and I still have fatigue and eyestrain / eye twitching. So it does not seem to be color temperature related.

Seagull

AGI

I don't know, I'm not familiar with fluorescent bulbs. Perhaps your lower power fluorescents have less persistence, for some reason.

I also don't know if any overhead light is installed with proper ACDC power bricks - but if your light fitting was something elaborate that might be the only way to do it. The reason normal household LEDs don't have proper AC-DC rectification comes down to space, then weight, then cost. But if you are installing something fancy, with the wiring hidden in the ceiling, decent rectification, and hence no flicker LEDs is achievable.