there is an inexpensive 660 nm red light coming available… recommended
sofirn C01R
not affiliated, just a fan
Sofirn will also make a C01 with a 5mm 670nm red led. It is not available for preorder yet.
https://sofirnlight.com/c01-aaa-flashlight-5mm-3400k-led-95-cri-p0152.html
670nm beam might look weird.
If the final version still has this issue, you can probably fix it with d-c-fix diffusion film.
I will get one to compare, but I do not believe that there is much difference between a rated 660nm red led and a rated 670nm red led for the purposes of this thread.
thanks for your thoughts, and for taking the time to share links
I agree 10nm is not a significant difference
I prefer the 3 modes of the C01R 660nm
the C01 670nm uses a 5mm LED and has only one mode
there is no lens, so cant use dcfix
to hide artifacts in the beam, we can use sandpaper on the LED
Im not a fan
Progressive Myopia or Hyperopia Can Be Induced in Chicks and Reversed by Manipulation of the Chromaticity of Ambient Light
https://iovs.arvojournals.org/article.aspx?articleid=2127682
Results.: Red light induced progressive myopia (mean refraction ± SD at 28 days, −2.83 ± 0.25 diopters [D]). Progressive hyperopia was induced by blue light (mean refraction at 28 days, +4.55 ± 0.21 D). The difference in refraction between the groups was highly significant at P < 0.001. Induced myopia or hyperopia was axial as confirmed by ultrasound biometry. Myopia induced by 21 days of red light (−2.21 ± 0.21 D) was reversed to hyperopia (+2.50 ± 0.29 D) by subsequent 21 days of blue light. Hyperopia induced by 21 days of blue light (+4.21 ± 0.19 D) was reversed to myopia (−1.23 ± 0.12 D) by 21 days of red light.
Conclusions.: Rearing chicks in red light caused progressive myopia, while rearing in blue light caused progressive hyperopia. Light-induced myopia or hyperopia in chicks can be reversed to hyperopia or myopia, respectively, by an alteration in the chromaticity of ambient light. Manipulation of chromaticity may be applicable to the management of human childhood myopia.
Good catch to find that interesting article from Dec 2013, i can only wish that red light could reverse my hyperopia (far-sightedness) to where i could see clearly again.
I see, myopia from exposure to Krypton’s red sun as a baby must be the reason why that journalist, Clark Kent, wears glasses. 
I guess I must be from Krypton too, given my myopia, but so far I can’t fly. 
Given all the blue light exposure we have nobody would have myopia if it had a strong effect on humans.
IIRC myopia may actually be correlated to lack of UV exposure as a children, so similar effect but the wrong wavelength on humans.
Edit: Other research says that myopia may be correlated to low brightness rather than low UV exposure, Why Outdoor Time Matters in Myopia Development - Myopia Profile , I’m not sure how reliable is that source.
People promoting alternative treatment saying that conventional treatment makes things worse in the long term, their information may be somewhat biased.
I didn’t know that clouds have fine details rather than just being white blobs until I got glasses, if someone had shown me a detailed photograph of a cloud before, I would have say that clouds don’t look that way, so I definitely had myopia before, but my myopia is slight (around –2.0 or –2.5), I could get out by foot without glasses if I wanted, only I would have trouble reading signs until I’m close. I don’t know if I ever will do the surgery because it may be not worth (for me).
I just learned that some colorblind people are a lot less sensitive to photo red. I wonder if anyone here has that issue and does not know about it. I wonder if that means that far red light, which most of us can still see, is completely invisible.
My test subject basically couldn’t even see the deeper shades of red. Like using some red emitters and adjusting the brightness showed he was 25x less sensitive to photo red than I was. So that much-lauded R9 number is basically worthless to the red-green colorblind. (The other types are so rare to not be worth considering.)
If they have reduced red perception they may be able to see other colors but I would expect that far red would be too faint.
If they just lack the L cones that discriminate between green and red they won’t be able to see it at all or at least have big issues seeing it. If you trust the Wikipedia graph, M cone sensitivity pretty much goes to 0 at 660nm and beyond.
OTOH IIRC someone (you?) in this thread have said that they can tell apart 660nm and 730nm by color. The cones can’t detect wavelength directly, the color perception comes from the difference between each cone signal. If the signal from the M cones is already at zero you shouldn’t be able to tell the two wavelength apart, unless you have 4 types of cones (the extra cone is between M and L cones). Of course it could just be ambient light messing with the color perception.
I can see that my XP-E2 Far Red 730nm flashlight looks slightly less orange on a neutral background than SST-20-DR 660nm.
The dominant wavelength for a 660nm led is probably about 645nm. Since these leds are not pure emitters of just 660nm or 730nm wavelength of light, I am probably just seeing orange because of the portion of emitted light that is below (for example) 640nm.
it was 620 and 660
further up this page I also posted 660 and 730, but the difference is not as obvious in a photo. They still look different side by side (the 660 is more orange than the 730). Plus 730 is like 100x less visible (less bright).
However, even if we cant see it, 730, 810, 900nm all have therapeutic value,
so do 620 and 660nm, and those are easy to see.
so for light therapy, being color blind is not an obstacle
1 Thank
AFAIK we don’t know whether therapeutic value (if there is any beyond placebo) is affected by color blindness. We would need a study for that.
the mechanism of charging mitochondria is not dependent on being able to see the light
and the mechanism of using a red light to relieve arthritis and migraine pain, has nothing to do with being able to see the light. It works even with eyes closed 
Have yall been seeing TV ads for the laser hair-growth caps—one site indicates they are using red @ ~650nm.
don’t know if these are just red leds or actually laser diodes, but they aren’t budget items.
capillus website: “Capillus laser therapy devices use only medical grade laser diodes as a light source. ”
Hi guys,
Would this red light be sufficient for the red light eye therapy?
Welcome to the forum Edel21
in my opinion, no, because it seems to use cool white LEDs with a red lens.
Not an actual pure Red spectrum LED.
Instead, I suggest you buy a Sofirn C01R
it has a 660nm Red LED, and the driver has 3 modes.
imo the second mode is sufficiently bright for eye therapy
Thank you Jon!
From reading through the forum Jon, I can see you’ve been using this torch yourself. Do you still practice the red light therapy? Do you hold it at 10 or 28 inches away from the eyes? Do you keep your eyes closed throughout? And is it 3 minutes for each eye?
yes I still use red light to wake up my eyes in the morning
I do keep my eyes closed, and I hold the light about 12 inches away. I move it up and down and left and right, because my reading is that movement helps jump start the nerve signaling, in addition to the red light charging the mitochondria
I dont do 3 minutes, I usually stop in less than 1 minute, but no harm in going a bit longer
as an alternative, you can do the same with morning sunlight. At around 10am the intensity is similar to the red light in the study. You will find this is actually quite noticeable through closed eyelids, and the red light I use, at the distance I use it, is actually less intense than morning sun.
I point that out so you have a reference to gauge how close you can hold the red light, without exceeding the intensity of morning sunlight.
I also use red light on painful spots, sore joints, sore muscles, even painful pimples… The red light seems to stop pain, for an hour or two. I notice pimples dry out and heal faster, overnight, instead of a few days.
My daughter who gets migraines, solved the problem shining a red light in her nostrils, for about 30 seconds each. An hour later she reported no Migraine, and the next day it did not return. There are a lot of nerve endings to the brain, at the back of the nose…
I also use red light for sore neck and headache, applied to the painful area.