What a fascinating analysis Jon Slider! Thank you.
As a layperson with zero medical or scientific knowledge I can only try to emulate what exerts have already researched.
My desire is not to improve my vision in any way but as a 66 year old film colourist I am concerned in retaining my colour perception after reading this article Declining eyesight improved by looking at deep red light | ScienceDaily
Quote from the article:
So without any knowledge and time to research, I am hoping to at least start from the same place where other expert researchers already found success.
I share your interest in preserving vision, and hope you find the dosing and other info you seek, to be comfortable using light therapy.
Since the LUMEN output of my red light is different from the output of the red light in other studies, and I dont have a sofirn C01S
the Distance to obtain a similar brightness on target, LUX, will be different for each output level.
I will be interested in learning how to do the distance calculation that equalizes for variations in lumen output of different flashlights, if you manage to sort it out.
I hope you enjoy whatever red light you choose… I recommend the experience… its fun, at my age… lol
Thank you. I did already buy the Sofirn C01R Red light and will definitely post any scientific empirical information which may be of interest to others.
Unfortunately CREE doesn’t indicate their measuring distance to determine the radiant flux for the XP-E2 photo red emitter used in the C01R flashlight. But as a worst case, their minimum was on the order of 450mW @ 350mA current.
They have wavelength bin P5 that ranges from 665 to 670nm, if someone wanted to push toward a custom emitter for mitochondria stimulation.
The flashlight specs indicate 3 modes with 0.5, 9, and 36 lumens, but no current values for the modes.
Vision Advisory
WARNING: Do not look at an exposed lamp in operation. Eye injury can result. For more information about LEDs and eye safety, please refer to the LED Eye Safety application note.
[edit: it seems that it should be possible to calculate the irradiance (mW/cm^2) that is hitting the pupils if the flashlight was mounted at a fixed distance from the face—but i think the measurement distance of the 450mW in the datasheet must be known first. Anybody have a clue on that?]
Found this 940nm SK98 for sale @ FastTech. As a zoomie it should project around ⅔ of its rated emitter output out the front in flood, in an ultra evenly distributed blanket of near infrared light. I wonder about the type and quality of the driver it employs, as the ∅20mm one inside the more standard XM-L2 version is a quite poor unregulated MOSFET (9435 p-FET) high / low / strobe unit.
Is this flashlight probably meant to be used with night vision devices?
Hi Glen and thank you for posting here and offering to respond if possible: I read through all your literature on PubMed and find your results wonderfully interesting and exciting for the future of medicine.
If 10am is the time to do it for mice then it is OK for me too!
One question in regard to photobiomodulation . All your references to light power use figures like (40 mW/cm2, 36 J in total)
I am a layperson with zero biological or scientific knowledge: what does this figure represent?
I bought a ‘Sofirn C01R Red light Keychain Flashlight Cree XPE2 660nm Deep RED LED bulb’ which has varying beam strength on different settings and can be quite intense on the highest setting. I can measure it in lumens with a light meter but how do lumens convert to the settings you use? Is there a conversion formula?
Oh and can one close the eyelid or is it best to maintain the colour and keep the eye open?
As a 66 year old film colourist with excellent colour perception I am only interested in maintaining my career as I age further.
I don’t want to blind myself in the process!
This has gotten me curious about building a simple measurement device for the radiant power. There used to be some ics TSL 235, 237… from Texas Optical to convert light intensity to either a frequency pulse or in some cases an amplified analog voltage proportional to the irradiance (mW/cm^2).
i ordered a photo red flashlight just to do this test and maybe the mitochondria testing also, but hopefully i can get some data about the C01R radiant power vs distance.
Everyone to his own. Quoting again to Glen Jeffery:
Far red emitters are ≈730nm. This is still visible and better suited for this photo-stimulation thing. Or are you waiting for someone else to come here and say this?
This stuff sort of draws my attention, but at this point I have plenty of other things to mess with, though.
Effects from 2-3 mins lasts about 3 days. No point in saying this to some people as they forget which day they used it - so say daily as there is no harm in it.
Green does not work - mitochondria do not absorb green light. A company has incorporated green into one device to make it more complex and protect their patent.
Longer wavelength penetrate deeper in tissue - so labs doing this in brain use 810nm or longer, which is beyond the human visual range.
No point in trying to work out wavelengths with your eye. You need a spectrometer
“(LEDs) … have photobiostimulative effects on tissue repair.
…
we investigated the effects of … green (518 nm) LEDs on wound healing.
…
wound sizes in the skin of … mice were significantly decreased on day 7 following exposure to green LEDs
…
In conclusion, we demonstrate that green LEDs promote wound healing”
I’m unsure of this. Not everything published is correct, particularly if there is a commercial interest behind it. But as you say it could be simply by another mechanism e.g. all light carries energy which can improve circulation, which in turn will likely improve wound healing
How big is the effect in practice? I understand statistical significance, but I realize that could mean an effect that’s reliably detectable but trivial for actual daily life purposes.
Reasonable point. Most people don’t detect anything obvious, although a couple of subjects did pass comment on colour perception changing. However the effect is robust when tested. One subject had a 20% improvement in colour contrast, which is not only significant but will impact on daily life.
Many things happen to your visual system that you do not detect. Glaucoma is a good example. There is significant slow peripheral visual loss that is often not detected directly until people start bumping into things that they walk by. The visual system slowly corrects for problems, it re-sets the gain control gradually, but over years things are lost. By the time you are 70 you have lost 30% of your central photoreceptors, but it’s a slow change and you only notice it when forced to make a visual judgement. People certainly notice loss of sensitivity in reduced lighting when they have to dark adapt and we have been working hard on that. We measure how long it takes them to adapt and show them the times and they are surprised how long it has taken. We show then show the times again after 670nm exposure and its obvious there is an improvement.
Our improvements will likely make a difference when you have to make a visual decision e.g. can you see something in the dark, can you detect a subtle colour shift. Its all about paying visual attention, which we often fail to do.
Sorry if the is a bit of a ramble but your point is important because people don’t know about how subtle visual decline is until a critical decision is needed. I think that is where it is obvious.
