Comment by weinzierl

"If you’re colorblind, I don’t think these will work, though I’m not sure."

Should work for anomalous trichromats (by far the majority of people with color deficiencies) but probably with less intensity.

"Folks with deuteranomaly have M cones, but they’re shifted to respond more like L cones."

I don't think this is true. What would the difference between deutan and protan then be?

"Why do you hallucinate that crazy color? I think the red circle saturates the hell out of your red-sensitive L cones. Ordinarily, the green frequencies in the background would stimulate both your green-sensitive M cones and your red-sensitive L cones, due to their overlapping spectra. But the red circle has desensitized your red cones, so you get to experience your M cones firing without your L cones firing as much, and voilà—insane color."

I think only people with missing L cone (Protanopia) or M cone (Deiteranopia) would not experience the phenomenon at all.

Maybe this could be used as a new type of color deficiency test?