Has anyone used red light therapy/photobiomodulation? What wavelengths/intensities are best?

[Alex K Chen]

 

https://www.getchroma.co/p/8-the-complete-solution-to-human

https://www.getchroma.co/p/15-were-gonna-need-a-lot-more-watts

https://www.getchroma.co/archive

I have access to a https://getchroma.co/product/chroma-ironforge/ in SF

Is it safe to use on the eyes? Can it get through the skull into the brain?

I know Vielight is a form of photobiomodulation too, though very expensive. It is possible to do trials in Toronto

 

Edited March 3 by InquilineKea

[Alex K Chen]

Quote

 

Functional near-infrared spectroscopy (fNIRS) using 700–900 nm light has been established as a brain imaging technique that can be compared to functional magnetic resonance imaging (fMRI) [32]. Haeussinger et al. estimated that the mean penetration depth (5% remaining intensity) of NIR light through the scalp and skull was 23:6 + 0:7 mm [33]. Other studies have found comparable results with variations depending on the precise location on the head and wavelength [34], [35].

Jagdeo et al. [36] used human cadaver heads (skull with intact soft tissue) to measure penetration of 830 nm light, and found that penetration depended on the anatomical region of the skull (0.9% at the temporal region, 2.1% at the frontal region, and 11.7% at the occipital region). Red light (633 nm) hardly penetrated at all. Tedord et al. [37] also used human cadaver heads to compare penetration of 660 nm, 808 nm, and 940 nm light. They found that 808 nm light was best and could reach a depth in the brain of 40–50 mm. Lapchak et al. compared the transmission of 810 nm light through the skulls of four different species, and found mouse transmitted 40%, while for rat it was 21%, rabbit it was 11.3 and for human skulls it was only 4.2% [38]. Pitzschke and colleagues compared penetration of 670 nm and 810 nm light into the brain when delivered by a transcranial or a transphenoidal approach, and found that the best combination was 810 nm delivered transphenoidally [39]. In a subsequent study these authors compared the effects of storage and processing (frozen or formalin-fixed) on the tissue optical properties of rabbit heads [40]. Yaroslavsky et al. examined light penetration of different wavelengths through different parts of the brain tissue (white brain matter, gray brain matter, cerebellum, and brainstem tissues, pons, thalamus). Best penetration was found with wavelengths between 1000 and 1100 nm [41].

Henderson and Morries found that between 0.45% and 2.90% of 810 nm or 980 nm light penetrated through 3 cm of scalp, skull and brain tissue in ex vivo lamb heads [42].a

 

The red ironforge:

Quote

Meet the REDFORGE: Since people keep asking us about red light, and since red LEDs are actually cheaper than near-IR LEDs, we decided to make a red light version called REDFORGE and it’s only available in the Black Series, which offers the most power. We split the power 50:50 between 670nm and 630nm LEDs, which are a bit more aligned with the cytochrome c-oxidase absorption peaks, though pricier than the standard 620nm and 660nm that is typically used. You may be wondering why we felt the need the need to add 630 when 670 is probably a bit better, and it has nothing to do with trying to offer more “features.” Near-IR is invisible so it doesn’t make for great marketing. 670nm is even dimmer than 660nm, but by adding in 630nm, we can increase brightness by 1.5x so it looks like more is going on — this will certainly be of uptmost important to everyone who couldn’t be bothered to

[I'm guessing penetration is lower for the REDFORGE red wavelengths relative to the near-IR]

Edited April 28, 2023 by InquilineKea

[Sibiriak]

Huberman discusses red light therapy for eyesight here:

The Science of Vision, Eye Health & Seeing Better 

https://youtu.be/ObtW353d5i0?t=4409

https://youtu.be/uWV9a3zEaL4?t=1807

(links jump to where red light discussion begins)

 

You can also search for Professor Glen Jeffery (University College London, Institute of Ophthalmology) who apparently is the leading expert on  the topic. 

[Alex K Chen]

I just applied too much too close too hard to my forehead and something stung and hurt. I'm okay but maybe I should hold it at a bigger distance next time.

(tbf this is the kind of impulsive behavior that could lead to accidents in some other scenario)

Edited April 28, 2023 by InquilineKea

[Alex K Chen]

https://www.linkedin.com/posts/joe-purita-md-00544423_light-stimulation-of-mitochondria-reduces-activity-7167887374109114368-NLu-?utm_source=share&utm_medium=member_desktop

https://onlinelibrary.wiley.com/doi/10.1002/jbio.202300521