Interesting. I’d guess it’s mediated by seeing the light, but there is a long history of “modern” research on red and near infrared light…see 1903 Nobel prize

https://www.nobelprize.org/prizes/medicine/1903/summary/

A few other lines of research here:

https://pmc.ncbi.nlm.nih.gov/articles/PMC8096326/

“In subsequent years, illumination of patients with red or infrared light, known as Photobiomodulation therapy (PBM), was proven clinically effective against a variety of human diseases including Achilles tendinopathy [3], Alopecia Areata [4–6], psoriasis [7–9], thyroiditis [10, 41], and arthritis [11–13]. A unifying feature of all of these conditions is that they involve excessive inflammation [3,5,9,14]. In particular, thyroiditis and psoriasis are both autoimmune conditions caused by an exaggerated host immune response [9,10].”

So it’s not crazy to think light can modify / treat disease. It’s actually proven fact in well defined settings…and probably a ton more if people stop and look.