Update on Waveform lights (2700K and 3000K Centric Home)- they’re still ok for me if the bulbs are new, but they become highly toxic over time. They flicker more and more significantly over time until they fail completely by starting to blink on and off slowly. We put them in hallway fixtures in my apartment building so they were on 24/7 and after a few months I thought I must be imagining the bad effects as I walked down the stairs. They then started to be definitely toxic and I started looking for replacements. Around 7 months many were failing by visibly blinking. Coincidentally about that time I got both a $60 Opple meter and a professional UPRTek meter ($2500 meter for $800 used on eBay after waiting many months) and found dramatic flicker in the 7 month bulbs that weren’t visibly blinking yet and a bit more flicker in some 2-3 month bulbs than new bulbs. I’m putting data together for this and other lights to share - with you, the FDA, and connections in the engineering/scientific community, but the bottom line is that I’m fine with sunlight, candlelight, true constant DC LEDs (on simple battery circuits with no digital circuitry-controlled dimming), and seem to tolerate, rarely, extremely low flicker LEDs on AC power if the flicker pattern isn’t highly regular. Lots of LEDs that cause brain injury for me have flicker below what the Opple meter can detect (Opple can only detect to about 1% or so, but bulbs at least as low as 0.1% flicker can injure me). Opple can barely detect new Waveform bulb flicker - the pattern that repeats 120 times a second is quite complex/irregular within each 120th of a second, which may be why my brain can tolerate it when the bulbs are new. Unfortunately, an expensive professional flicker meter is necessary to detect the flicker of many harmful bulbs. The Opple meter is also tricky to use correctly as it flatlines artificially when the light is too bright and has too much noise when the light is too dim. With engineers and other scientists in the US, we’re trying to correlate flicker waveforms with degrees of toxicity, but it’s complicated (and so far only using my data on myself). It seems like the flicker waveform itself is by far the major part of the issue for me, but maybe not the only factor. Incandescents are much less toxic than LEDs for me too, much less than their flicker waveforms alone would seem to suggest. And when I do get sick from incandescents (usually during the acute LED injury recovery period), the effects are different - common migraine typically that can be quickly stopped with ibuprofen, instead of my concussion-like LED symptoms. It’s not totally clear what the key difference is, but possibilities are (some/most??) LEDs have slightly flickering colors due to phosphor light emission/decay not being completely in sync with the diode light or other phosphors, and incandescent flicker is mainly in the red/IR range, which might have different biological effects than LED flicker which has low red and almost no near IR/IR. There’s interesting tangential research in the literature on led therapy through tissue that shows various biological effects specific to the color and sometimes pulsing of light that may be relevant. Flicker meters, as currently designed, don’t measure color flicker. I’m using a portable UPRTek meter on a tripod, whenever possible, as hand-held readings aren’t stable enough unless the flicker’s really bad. I’m using camera color filters positioned over the meter to detect differences in color flicker. I have a lot of filters, but the most useful ones are the color-separating set of Wratten filters (Red 25, Green 58, and Blue 47), which I purchased as Tiffen glass camera filters that also fit my DSLR camera. The UPRTek data gives good enough data in excel files for analysis. I can also get good photos with and without the filters of those horribly toxic color-tunable LED bulbs by taking panning shots with the DSLR. Currently I try to only use sunlight during the day and at night I minimize the use of AC lights and, especially if I’m recovering from LED brain injury, try to mostly use candlelight and battery-powered LEDs - simple AA or AAA powered string lights put inside mason jars with diffusing liners like parchment paper. The diffuser is necessary to eliminate the little tingle of pain from looking right at the LEDs - I think they may feel too bright in an otherwise dark room (cooler light worse than warmer light), but this doesn’t seem to be triggering of brain injury for me. I’ve screened incandescents and am using the lowest flicker ones I could find or newish Waveform bulbs or some very low flicker 40W Sylvania bulbs when I need more light - trying to figure out which of those is the least harmful… currently leaning toward the incandescents for limited use, but I’m not sure…. Beware battery-powered LEDs with dimmers - one of my worst brain zaps came from a dimmed battery LED lamp - flickering much faster than my phone could detect on slo mo, but in a complex, unique pattern - at least 40000 peaks per second but the peak amplitudes varied in slower periodic patterns. We really need to see flicker waveforms and not rely on calculated flicker metrics or just phone slo mo videos to keep ourselves safe. If anyone else is able to collect and would like to contribute data linking flicker waveforms to symptoms or lack of symptoms, you can share it with the FDA Office of Radiological Health. If you’d like to share it with the US engineers and scientists starting to analyze my data please DM me - especially if you can collect high-sensitivity data in Excel files with a professional meter. Also, everyone, please report health issues to the FDA if you haven’t yet done so -[ https://ledstrain.org/d/1798-how-to-report-health-problems-with-led-lights-or-screens ]

Interesting. I bought the Waveform light 5600k which according to Opple findings should be ideal. However the moment I inserted the bulb, I immediately felt severe discomfortable and a migraine followed shortly within 4 minutes. This usually happens if the I cognitively percieved that the flickering is very harsh. The bulb was used in a mini studio size bedroom 13ft x 11ft by 8 feet high, thus proximity between source and my eyes does play a role in my susceptibility to the flicker. They flicker more and more significantly over time until they fail completely by starting to blink on and off slowly. When you brought up that they flickered more and more significantly over time, were they flickering low to a point it resembles like a circuit overload? Etc ; sudden rapid dimmed light flickering over 3~ 4 seconds intervals where it may even be visually percievable at times, and suddenly brightened up again and repeat? the effects are different - common migraine typically that can be quickly stopped with ibuprofen, instead of my concussion-like LED symptoms. Same. For a period I relied heavily on a daily dosage of naproxen 250g(strongly not recommended) to help me cope with my daily exposure to fluorescent lighting. The Waveform lighting bulb is really something else. Even a doubled dosage of 500g were completely ineffective against the migraine pain, brain fog, light-headedness and spinning sensation (probably vertigo migraine, but its very rare I'll have them unless I stared into slow flashing alternating of colours, like between extreme red and blue light spectrum e.g. the pokemon seizure episode that made over thousands of children unwell). Beware battery-powered LEDs with dimmers - one of my worst brain zaps came from a dimmed battery LED lamp - Exactly! It is way too stimulating

Opple can only detect to about 1% or so, but bulbs at least as low as 0.1% flicker can injure me That's what the evidence points to for myself, too. Symptoms with every LED bulb I have ever tried - and I bought the low flicker and "flicker-free" ones, the latter which also measurably flicker. Some of them are below 0.1%, but still: eye strain and headaches over time. Then there is this bulb that has some kind of non-fixed but instead variable high flicker frequency (somewhere at xx kHz IIRC), which makes me feel truly sick after just a few seconds. I have also found that my TV causes symptoms when the 20 kHz flicker amplitude gets too high (at low brightness levels). So the safe frequencies and their corresponding amplitudes vastly differ from what's currently recommended in those current safety standards' papers.

Tobiyas When you brought up that they flickered more and more significantly over time, were they flickering low to a point it resembles like a circuit overload? Etc ; sudden rapid dimmed light flickering over 3~ 4 seconds intervals where it may even be visually percievable at times, and suddenly brightened up again and repeat? At first, the amplitude of the peaks just increased until the flicker eventually became 100% in a 120 hz pattern that I could feel as pain, but couldn’t “see.” I needed the meter. Later, the bulbs started to be off mostly, regularly flashing briefly on at a frequency around once a second. I’m curious about whether all LED bulbs flicker more as they fail or if something else can happen. Is the failure mechanism an accident or is it being engineered? I just learned about the Phoebus Cartel - apparently early incandescents lasted too long so to boost sales starting in the 1929d and 30s the lighting industry started to engineer in failure at 1000 hours and fine each other for exceeding that. https://www.npr.org/2019/03/27/707188193/the-phoebus-cartel [ https://www.newyorker.com/business/currency/the-l-e-d-quandary-why-theres-no-such-thing-as-built-to-last ] The Phoebus cartel broke up, but limiting the life of a incandescents continued. I wonder what the practice is for LEDs.

KM Then there is this bulb that has some kind of non-fixed but instead variable high flicker frequency (somewhere at xx kHz IIRC), which makes me feel truly sick after just a few seconds. Same. I accidentally turned on the battery- powered LED lamp taking it out of the package and its initial dimmed setting with a flicker frequency at least as high as high as my meter could detect - over 40 kHz with a complex pattern, felt like an immediate electrical zap that moved around my brain. I had never experienced such an intense effect before. I immediately switched off the lamp, but very intense nausea came right after the brain zap for a couple moments and then, of course, my typical long-lasting concussion- like symptoms from LED injury slowly built up over the following hours. The lamp had no flicker at full brightness and didn’t affect me at that setting, but it was too dangerous to keep. Some of them are below 0.1%, but still: eye strain and headaches over time. I don’t get eye strain ever, but head pressure, headaches, working memory impairment and lots of other neurological symptoms- even some Ikea LED bulbs with less than 0.1% flicker can trigger my symptoms, but just more slowly and initially less intensely than LEDs with more severe flicker.

jen Great to see you on here. @jen , you might like: Flicker Alliance , or, Light Bulb Database which measures LED light flicker . Peter Erwin as an electrical engineer has excellent website . /u/the_top_g also an engineer, has some great posts on Reddit. He came up with his own formula for LED safety that is stricter than IEEE 1789, which is: Acceptable modulation percentage = 0.08 * PWM hertz if(window.hljsLoader && !document.currentScript.parentNode.hasAttribute('data-s9e-livepreview-onupdate')) { window.hljsLoader.highlightBlocks(document.currentScript.parentNode); } # For example: # BedTime Bulb has 120Hz flicker with Flicker Depth of 1% 0.0025 * 120Hz = 0.3% That means the flicker cannot exceed 0.3%. Since 1% > 0.3%, the bulb is NOT safe, according to this formula. if(window.hljsLoader && !document.currentScript.parentNode.hasAttribute('data-s9e-livepreview-onupdate')) { window.hljsLoader.highlightBlocks(document.currentScript.parentNode); }

ryans Flicker Alliance , or, Light Bulb Database which measures LED light flicker . Peter Erwin as an electrical engineer has excellent website . @ryans Thanks for the links! I’m familiar with these and link to Peter Erwin’s site on www.FlickerSense.org . The FlickerAlliance site is a good start and admirable effort, but this kind of site needs some modifications before it can approach being a way to find safe bulbs, even if we knew the difference between safe and unsafe flicker, mainly because the Opple meter unfortunately isn’t sensitive enough and can also give misleading risk reports, especially when its flicker calculations fail. And the IEEE “risk” chart it includes is highly misleading since it’s an outdated chart of risk of flicker visibility , not health risk - there is no health data yet for LED flicker at and above 100 Hz. I’ll be referencing the site when I post my data - I tested all of the lowest flicker Sylvania and Ikea bulbs from the site whose flicker in the waveform graphs was below the level of detection of the Opple meter, some down to 0.06% flicker, and they all trigger brain injury for me, although among these, the 40W 2700K Sylvanias take much longer to start symptoms than any of the others I tested from the site. It would be really helpful if someone with more capacity for screen time than I could use a much more sensitive meter than the Opple meter to post detailed flicker waveform data for a lot more LEDs, including detection of color flicker - it would make sense for manufacturers to be required to report to a centralized database. It seems that once you’re dealing with very low flicker, the flicker pattern becomes very important in terms of whether symptoms start, how quickly they start, and what form the symptoms take, at least for triggering concussion-like symptoms for me. For me, some seemingly safe LED bulbs have higher % flicker than some quickly injurious LEDs, but the patterns of 120hz flicker are quite different. An IEEE-like chart of %flicker vs. frequency probably won’t be sufficient to define safety since it doesn’t show flicker pattern. To figure out the difference between safe and unsafe flicker patterns generally, more waveform and health data, especially for other people too, will be needed. We’ll also need to know how flicker changes as bulbs warm up and as they age - some of the bulbs I’ve checked change after being on for several minutes. And so far I only have aging data for Waveform, which flicker more as they fail, but I’m concerned if this is a more general trend that would mean needing to regularly check LEDs with meters to identify bulbs with newly developed, dangerous flicker.

Try two bulbs with different flicker at the same time and see if it worse than two of the same. Sure seems like having things at different hz here is a surefire way to induce symptoms. Even having two different monitors with different refresh rates does. Like having the TV far way running behind the laptop. Maybe many of the issues are simply a timing issue in the brain, and adapting to it? Fair question, does anyone have screen sensitivity while outside? When the environment is brighter than the screen, and there are no artificial light (or sound). Would be interesting to hear from someone that has significant issues test a monitor outside. However would preferably be without highly dynamic refresh rate like ProMotion or VSync. Would also be interesting to hear if anyone experimented with music with a fixed beat, binaural beats or similar. Some proposed mechanisms from from ChatGPT. The potential discomfort caused by using two monitors with different refresh rates may indeed be rooted in neurological mechanisms, including the way neurons process temporal information. Here's a more in-depth exploration of the neurological basis: Temporal Integration and Neuronal Adaptation : Neurons in the visual system integrate visual information over time. When presented with stimuli at different temporal frequencies (i.e., from monitors with different refresh rates), these neurons might continually adjust their firing rates to adapt. For instance, certain retinal ganglion cells respond preferentially to temporal changes in light intensity. When visual input flickers (as in a lower refresh rate monitor or inconsistent refresh rates), these cells can increase their firing rate, potentially leading to a heightened sense of discomfort or visual fatigue. Visual Pathway Overstimulation : Neurons communicate using electrochemical signals, and a consistent or predictable rate of stimulation allows for regular periods of activity and rest. Inconsistent temporal input, such as switching between screens with different refresh rates, might result in irregular neuronal firing patterns. This irregularity can potentially lead to overstimulation or "overwork" of certain pathways, which might manifest as eye strain, headaches, or even migraines in sensitive individuals. Cortical Processing and Attention : The primary visual cortex and higher cortical areas responsible for attention and object recognition might experience increased demands when processing differing temporal inputs simultaneously. This increased demand might lead to a sensation of "mental fatigue" or difficulty in concentrating, especially during tasks that require shifting attention between the two screens frequently. Mismatched Multisensory Integration : If one is using both screens for a task that involves motion and sound (e.g., video editing), there might be a mismatch in how the brain integrates visual and auditory information due to the difference in refresh rates. The brain is adept at synchronizing visual and auditory cues, but discrepancies introduced by differing refresh rates might pose challenges in this multisensory integration process, potentially leading to discomfort or disorientation. Interhemispheric Communication : Visual input from each eye is processed in both hemispheres of the brain. If each eye is predominately focused on a different monitor (left eye on the left monitor and right eye on the right monitor), and each monitor has a different refresh rate, it might introduce disparities in the visual information processed in each hemisphere. Efficient interhemispheric communication is crucial for unified visual perception. Disparities in temporal processing might pose challenges to this communication, leading to potential visual discomfort.

Or just take an extension cord and bring out your worst bulb. See if it is problematic outside.

jen thanks @jen . Are the Phillips model 9290002268 still the best LED for you? Unfortunately in USA the incandescent / halogens have been banned, however, appliance incandescent (like for an oven) should still work in a regular lamp. I've heard good things about Avulux / Axon glasses too.

Yeah, oven bulbs are 40w but make sure you don't get one that is 130v, otherwise subtract 25% from the lumens.

Measuring LED flicker - correlation with health symptoms

photon78s

jen

This link is about a "low emissions computer" project relating to EMF sensitivity not specifically LED flicker. They use incandescent light for the display and a rear projection system. What I find also interesting is that it was funded by US Department of Education and the National Institute on Disability, Independent Living, and Rehabilitation Research.

http://asilo.com/aztap1/

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