FL-41 filter Glasses

jasonpicard Thanks! So you are saying that Theraspecs or whatever blocks blue light do not help in case of flickering LEDs, but you do still use such glasses in a flicker free LED environment because at 6500 K there is plenty of blue. Hence your conclusion is that you are sensitive to both flicker and blue light. Is that a correct summary of your condition and findings?
The temperature of my light tubes in the office is 3000 K! I hate talking of feelings, but paradoxically I feel low temperature bothers me more. Maybe I should get a higher temperature bulb up on the ceiling and see how it goes. Yesterday I was in the office until night. It took me ages to write an email. I went home, took a break for dinner, sat under my fluorescent overhead light at home and I was much more performant. That light is clearly more blueish. How come if blue is evil?

AGI I use SCT orange. I know Theraspecs are a scam and I'm not a fan of them because I think they are scamming people because they used to market them as blocking wave lengths for CFL. I wore my Theraspecs to my work one day and after 1 minute thought I was going die. They don't block any blue light the way they are claiming. This is not really an issue with CFL because it barely has any blue light compared to LED. SCT orange with black electrical tape on the sides and a ball cap so I block light from all sides. When it comes to light bulbs yeah blue light and flicker are my main problems.

I'm not able to use LED bulbs and monitors without pain even when they're flicker-free (aka very low flicker, as they all do flicker a little) and I wear orange blue-light blocking glasses. I have checked the latter actually block blue by using a handheld spectrometer. I have no idea what's going on actually. This condition is truly disastrous. I have even tried frosted glass in front of the bulbs, while making sure no light could escape from the sides. It did not help at all. I compared online charts of different light spectrums. It seems natural daylight has pretty much all wavelengths at extremely high intensity yet it causes no pain at all. So unless for some obscure reasons the relative wavelength distribution is more important than the absolute intensity I'm not sure if any filter glasses could ever help in any way.

KM unless for some obscure reasons the relative wavelength distribution is more important than the absolute intensity

Yeah, that is what I had thought too, and that is why I am considering the glasses. I do have orange UVEX goggles worth USD 10. They do not help, although I verified with a spectrometer they effectively cut blue and green. The optician says the low quality of those lenses may cause more downsides than benefits, but I have not yet fallen to purchase his Nikon lenses which are over USD 400 inclusive of frame.

I am really desperate and wondering whether it is worth to eventually waste other bucks rather than sit here and do nothing. That for sure is not leading anywhere. To be honest the main reason why I have not yet made the investment though is that the guy showed me a bunch of lens colors from bluish, purple to yellow, but was unable to tell me why one rather than the other. That proves to me that, no offense, he is not competent. "Some people find a certain color more comfortable" is not a satisfying scientific / technical explanation. I won't be allowed to swap lens color if it does not work.

KM I have LED bulbs that flicker just minimally at 100 Hz below 0.1% (almost not measurable) and they still hurt.

Have you tested / compared different temperatures, e.g., 3000 vs 6500 K, and CRIs?

With regard to color temperature:

...the use of warm colour temperatures at high illumination levels yields an unpleasant insipid yellow hue to the surroundings which disturb the feeling of well-being. The matching of the illumination level to the desired colour temperature is a key point that is often overlooked in modern lighting design.

With regard to CRI:
Consider the appearance of people and objects under daylight. They tend to look great, right? Well, the CRI of daylight is around 100. Contrast this to an orange street light, where it’s hard to discern the color of anything. That street light has a CRI close to 0.

Maybe flickering is a red herring, and I am going nuts because of poor CRI and illuminance / color temperature combination?

AGI Yes I have like 30 LED bulbs, most warm-white but some with different temperatures. It seems for me it doesn't matter much if they are blue, violet, yellow, or orange. The last bulbs I bought were advertised as flicker-free (surprisingly they are not!) and CRI/RA95. The high color index was the reason I had bought them. Still eye strain, even from the one bulb that is flicker-free. I followed a link in some thread here to the Blurbusters forum where the admin spoke of an upcoming new generation of LED bulbs that use a violet chip instead of a blue one, giving a more natural spectrum. But it seems they are not available yet. What the bulbs I have so far all have in common color-wise is a lack of red. I wonder if a bulb with no blue chip but just a regular red one would work. Problem is there are red bulbs but you don't know what's inside (could be blue with red coating) and none of them are labeled or tested flicker-free so I didn't try those yet.

I also bought CRI97 bulbs that flicker and hurt.

KM Uh, that sounds like a very thorough investigation. Thanks. I am even more discomforted then.

I was reading about Kruithof's graph, dated 1947, on the matching of illumination level and color temperature for pleasant indoor lighting, and found it is considered obsolete / incorrect by many. This open-access paper concludes illuminance is way more crucial than color temperature.

ABSTRACT

Kruithof’s graph identifies combinations of illuminance and correlated color temperature (CCT) alleged to yield pleasing visual conditions for interior lighting. Though in research terms the support provided by Kruithof is insufficient, it is widely cited as a design rule and has been the focus of many experimental studies despite evidence against Kruithof since at least 1990. The current article examines the trends displayed in those studies considered to provide credible evidence: these do not support Kruithof. For pleasant conditions, these data suggest only avoiding low illuminances and do not favor any CCT.

This is quite in line with my recent observations, that the same fluorescent tubes hurt if run at low power / low illuminance, and do not cause major eyestrain / fatigue at high power in brighter rooms. It sounds a bit simplistic though, as my symptoms are pronounced and their onset immediate. I surfed thru the article and could not clearly understand what the metrics employed for judging pleasantness are.

Just shooting in the dark. I am pretty sure you have already explored the illuminance variable, @KM?