Red light improves your vision, and it does so with your eyes open. In a normal red light therapy session for the face, you close your eyes. These are two different uses, and the difference is not the colour of the light but how much of it your eyes take in.
| Eye protocol | Therapy panel | |
|---|---|---|
| Wavelength | For example 670 nm only | 660 and 850 nm together |
| Intensity | weak, about 8 mW/cm² | many times higher |
| Duration | three minutes | 10 to 15 minutes |
| Eyes | open, you look into the light | closed, or protective goggles |
Red light improves vision. Researchers at University College London measured 17 percent better colour contrast sensitivity in people over forty after a single three minute exposure to 670 nm, and a week later 10 percent of that was still there. The source was weak: 8 mW/cm² at the cornea, given in the morning. The same test in the afternoon did nothing.
A therapy panel is many times brighter. You need that intensity for skin, joints and muscles, but not for the retina, and no research supports that kind of dose on open eyes. That is why the rule with a panel is: eyes closed or goggles on. Not because red light damages the eye, since it falls outside the wavelength range where UV damage happens, but because your eye does not need that much light and you end up squinting without meaning to.
What we recommend for improving your eyes, and with which lamp, is in the article Protocol for improving your eyes. More on how it works is in Does red light therapy work?, and the practical questions about duration and frequency are in the FAQ.
Sources
- Shinhmar H, Hogg C, Neveu M, Jeffery G. Weeklong improved colour contrast sensitivity after single 670 nm exposures associated with enhanced mitochondrial function. Scientific Reports 2021;11:22872. A single three minute exposure, 8 mW/cm² at the cornea, nine LEDs behind a diffuser. A 17 percent improvement on the tritan axis three hours later, and still 10 percent after a week. Only with morning exposure.
- Shinhmar H, Grewal M, Sivaprasad S, Hogg C, Chong V, Neveu M, Jeffery G. Optically improved mitochondrial function redeems aged human visual decline. The Journals of Gerontology: Series A 2020;75(9):e49-e52. Two weeks of 670 nm in participants aged 28 to 72. Colour contrast and rod thresholds improved significantly over forty; no effect below that age.
- Grewal MK, Sivapathasuntharam C, Chandra S, Gurudas S, Chong V, Bird A, Jeffery G, Sivaprasad S. A pilot study evaluating the effects of 670 nm photobiomodulation in healthy ageing and age-related macular degeneration. Journal of Clinical Medicine 2020;9(4):1001. Daily 670 nm improved rod function in healthy ageing, but showed no measurable difference over twelve months in people with intermediate macular degeneration. So the effect is not the same everywhere.
