Show Notes

PHOTOBLEACHING

You may be familiar with photobleaching. This is the process by which photoreceptors are saturated with light, and therefore stop working temporarily. This was once a fad on youtube to use your phone flash, shining through your eyelid – thereby being filtered red by your blood – to saturate your red cones and experience temporary colorblindness. So what’s the difference between bathing your retina in red light to experience colorblindness and bathing your retina in red light to experience the opposite? As far as I can tell, it’s only the time scale. The effect on the opsins lasts only seconds or minutes, while the effect on the mitochondria lasts days. I’ll make a video about the photobleaching fad in the future.

DICHROMATS

If you are colorblind, not only will the therapy likely not help you, if you are a dichromat (e.g. protanope or deuteranope), i.e. missing an entire color channel, either blue-yellow in tritans or red-green in protans/deutans, this therapy cannot help your missing channel, but could still help your remaining channel. So as a protanope, I could still receive a benefit in my blue-yellow channel, but not my non-functioning red-green channel. The age-related caveat still applies.

TRITAN

In this and all previous studies, there was a stronger effect on the tritan axis than the protan. This is supposedly because the S-cones have much fewer mitochondria and so show the signs of mitochondrial decline much earlier. Interestingly, the lack of mitochondria in S-cones is ostensibly because mitochondria absorb 420nm blue light. Because light must travel through the body of the photoreceptor before reaching the opsins (and therefore, the mitochondria), minimizing the number of mitochondria maximizes the blue light that can reach the S-opsins, which are intended to absorb 430nm blue light.

MORNING

Funnily enough, the photobiomodulation is only effective when the therapy is applied in the morning. If it is performed midday, there is no effect in either the short term or the long term. That is because the mitochondria don’t do the same thing all day long, they have a certain circadian rhythm, where they perform different tasks during different times of the day.

Transcript

Hi… I wanted to interrupt my normal flow of videos this week to talk about a paper that was published in November of last year that discusses an incredibly simple method for improving your color vision called photobiomodulation.
This group of researchers has been studying this phenomenon since about 2014 and has been doing so with human trials for the last few years… and this new paper shows results that look downright stupid and yet at the same time incredibly compelling.
So today on Chromaphobe, let’s look at what photobiomodulation means for colorblindness. The basic idea behind this photobiomodulation therapy is that you shine a red light into your eye for three minutes. After several hours, there is a measurable effect, in that your color contrast improves by about 15 percent, which can be maintained then by daily treatments.
But no need to walk around like jordi laforge because this new study shows that after just a single three-minute exposure, the improvement to your color contrast is still mostly there a full WEEK later.
Now, shining a red light in my eye seems like it would have been something I would have relegated to my recent video on pseudoscience and to be honest it doesn’t sound that much better than color puncture, but the methodology of this study seems relatively sound despite the paltry sample size of 20 individuals and really it’s just aggravating how simple it is.
This therapy isn’t exactly revolutionary though. Photobiomodulation – known historically and more descriptively as Low-Level Laser Therapy (LLLT) – has found some potentially useful applications such as a mild non-invasive therapy for arthritis pain… but these weak findings have bolstered a torrent of low quality studies and misleading books that claim that red light can be applied to pretty much any disease or tissue imaginable including THIS single red led that you stick up your nose and costs an insane 750 bucks on amazon or this so-named “magic wand”… and i think you can guess where that goes.
The reason academia is so tolerant of this shotgun approach to finding possible applications for photobiomodulation is that the true target of the therapy is your mitochondria, which are everywhere in your body and affect every part of your physiology.
But let’s forget about all the other body parts… the illuminating nose plugs… and the magic wands… let’s just focus on the eyes for this video. Now, when you hear about a therapy that shines some light into your eye to affect your vision, you would be forgiven for thinking it’s obviously the opsins that are affected, but opsins actually have nothing to do with this effect. Rather, it’s the mitochondria that are affected, because – and say it with me now – mitochondria are the powerhouse of the cell. Your photoreceptors (specifically the cones) are gram-for-gram the most power-hungry cells in your body. Constantly powering the visual cycle and the phototransduction pathway means that they require a lot of ATP. Recall from high school biology that ATP is essentially your body’s universal energy currency that your cells use to power pretty much any process in your body including your opsins. All of that ATP has to come from your mitochondria (the little ATP factories) and therefore your photoreceptors are stuffed with mitochondria to make sure their metabolism stays high and your vision stays working smoothly. However, like an engine revving at high RPM, the mitochondria in your photoreceptors experience quite a bit more wear and tear than the mitochondria in your other cells and past about 40 years of age the mitochondria are unable to keep up with the intense energy demands of your photoreceptors and therefore your color vision starts to decline. The photobiomodulation therapy supposedly rejuvenates mitochondria. According to this paper, exposure to long wavelength light in the range of 650-900 nanometers improves mitochondrial function by increasing ATP production and reducing ROS. We covered the ATP part already, but the second part of that sentence is also quite interesting, because ROS or reactive oxygen species are byproducts of metabolism that generally stay within your mitochondria… but when the function of those mitochondria decline, they release more ROS because the processes they’re within aren’t so efficient and then those ROS act like little molecular hand grenades. As these ROS float around your cell indiscriminately blowing up important molecules, you can imagine why nutritionists are so gung-ho about antioxidants which essentially neutralize these ROS. So with more energy and fewer random hand grenades going off you can imagine that as a result your photoreceptors could run a lot more smoothly and as a result improve your color vision. How the red light actually affects your mitochondria is still an open question, despite the 50 years of research that’s been made to this phenomenon, but the leading theory at this point seems to be “a reduction in nanoscopic interfacial water layer viscosity around atp rota pumps”… Damn… microbiology is kind of hard.
Let’s talk more about color theory. In this context when I say improved color vision, the paper specifically means increased color contrast sensitivity… and let’s visualize this on a chromaticity diagram. Can you tell the difference between these two colors? Probably not. Actually, for color normals, everything inside this oval should appear to be the same color. If you see these two colors as different, then congratulations: you have a high color contrast sensitivity and to reflect your amazing color vision we have to decrease the size of this oval. In this hypothetical, you could now see more colors essentially because you can fit more of these ovals into this chromaticity diagram. These ovals are called MacAdam Ellipses and are used to visualize an individual’s color contrast sensitivity. The size and shape of these ellipses are defined by the color contrast sensitivity along the protan and the tritan axes.
Someone with protan color blindness would have poor color contrast sensitivity along the protan axis and so therefore, when we visualize their ellipses, they would be stretched out along the protan axis and look something like this.
Someone with protonopia – or full protein color blindness – would have an ellipse that stretches the full width of this chromaticity diagram. This oval would therefore represent a protan confusion line, such that every color along the axis of this oval look identical to protonopes like myself.
Now, if you’re a strong protan, you might be bristling right now and thinking “Of course I can tell the difference between those colors are you daft?” but notice I didn’t say colors, I said chromaticities.
If we adjusted the luminance of all of these chromaticities then – yes – the colors would also look identical to protanopes like me… but chromaticity diagrams are not made to be isoluminant to colorblind folk like myself. They’re made for color normals.
So to summarize, bigger ellipses means worse color contrast sensitivity. We would generally call that a color vision deficiency and smaller ellipses means a higher color contrast sensitivity. Once you know what it is, measuring color contrast sensitivity is quite straightforward and is done with a simple digital test. The test presents you with a shape or letter comprising a foreground and a background color… and these colors are chosen specifically to lie along the protan axis or the tritan axis.
The test then moves those colors closer together chromatically until you can no longer recognize the shape or the letter. At that point, the colors are close enough such they lie within the same MacAdam Ellipse and therefore look identical to you. The closer those colors are before the letter or shape becomes unreadable, then the better your color contrast sensitivity.
On the screen now are the improvements that the study found to both the short term and the long term color contrast sensitivity, as measured on the protan and tritan axes. These numbers mean that a week after the exposure, your MacAdam Ellipse in this area has been compressed 10% in one direction and 8% in the other direction – overall about 20% smaller meaning that your chromaticity diagram now holds 20% more ellipses and therefore you can see 20% more distinct colors… and this is a week after that one simple 3-minute exposure.
Certainly this big improvement made a huge difference into the visual experience of the subjects and the study had this to say: “Subjects were asked if they had thought their color perception had changed in their normal visual environment and around 10% reported a subjective difference.” Meaning that 90% of people didn’t even notice a change to their color vision, which I mean… it’s certainly not on par with the EnChroma Effect.
Speaking of EnChroma, how would this therapy affect our color blindness? After all, we all want a simple way to neutralize our color blindness and see color like a normal person. Unfortunately, that 15% improvement is relatively just… so small. The MacAdam Ellipse for someone with a mild form of CVD is perhaps about twice as big as it is for a color normal and for strong forms of CVD, it’s much bigger. Offsetting your CVD and shrinking your ellipse by 15% is technically helpful, but it’s not exactly bringing you much closer to what you would call “normal”.
The most important caveat on this effect, though, is that it should only be possible on aged mitochondria. In fact, a previous study showed that individuals below 40 didn’t really obtain a consistent effect from the photobiomodulation. If your mitochondria are young and not starved for energy, then theoretically, this therapy cannot have an effect on you. The boost to your color vision from photobiomodulation can only be as big as the toll that aged mitochondria SPECIFICALLY have taken on your color vision. So if you’re 20… regardless of your type of color blindness, it seems that photobiomodulation will most likely not have any effect on you.
This paper was actually brought to my attention via fellow youtuber Casey Connor, who took up the challenge to replicate the results on himself. He built these sick steampunk glasses, exposed himself to this red light therapy and tracked his progress with a homemade color contrast test. While his methodology is certainly admirably robust for a youtuber you have to take his results with a grain of salt because… Casey: “of course the big problem with my study is that it’s sample size n=1 and there’s no control and so forth.” Regardless, what he found with himself does mesh with the study’s results with a 24% and 5% increase to his color contrast sensitivity on the tritan and protan axes respectively.
The only question left is therefore: should I replicate this study on myself and obviously use my wife as a control? We’re not yet in the target age group – we’re both in our 30s – but the evidence that says it doesn’t affect anyone under 40 is circumstantial. So far, this method has never been tested with a colorblind individual, so replicating on myself could provide some interesting results – unlikely – but maybe. Let me know in the comments if you think that would be interesting, if only just for the LULZ.
The big problem with studies like this is not the study itself. In fact, this study comes out of the university college of london which has arguably the best ophthalmology department in the world. No, the problem with this study is the commercial reaction to it. The researcher’s conclusion of the study was obviously: “look, we’ve found a small effect, now let’s apply for a grant so we can get some money to perform a better designed study.” But it took only 2 months after the release of this paper for a third party – unrelated to the researchers, and in fact specializing in industrial lighting with no experience in biomedical devices – to start marketing this device “EyePower Red” as “essential eye care to anyone over 40.” Since january 2022, the week I am recording this video, you can now buy a pair and begin your futile attempt at curing your color blindness… but I can pretty much guarantee you that it is not going to have the effect that you want it to have.
I’ve put a few show notes for this video on my website: there’s a link in the description. The transcript is also there. So if you want to see a little bit more technical discussion on this study, you can find it there as well.
If you enjoyed this video please like, subscribe or share it with any colorblind friends that you might have. The next long-form video – as decided by the reddit poll from December – is going to be on the Evolution of Color Vision and it’s going to be so long i’ve actually broken it down already into three different videos. So thank you for watching and as always… this is Chromaphobe.