The Research Behind 670nm Light
Two decades of peer-reviewed work sits behind this wavelength. We've read it, listed it, and linked straight to the source — so you can check it yourself rather than take our word for it.
670
nanometres
the studied wavelength
20+
years
of published work
7
papers
listed on this page
2
of them
conducted in humans
Where 670nm Sits
Not ultraviolet. Not the short-wave blue people worry about. It's at the far red end of what your eye can see.
Both wavelengths MEINNO uses sit well clear of the short-wave region below 450nm. Every model is UV-free and tested to the IEC 62471 photobiological safety standard.
Read this first
Every study below examines 670nm light in general, using research-grade equipment at controlled doses. None of them tested MEINNO. We link to them because we think you should be able to read the evidence yourself and reach your own conclusion — not because they describe what this product will do for you.
The Library
Grouped by what kind of study it was. The number on the left is the one figure worth remembering from each.
Human studies
Conducted in people
20
adults
aged 34–70
Weeklong improved colour contrast sensitivity after single 670 nm exposures associated with enhanced mitochondrial function
A single three-minute morning exposure to one eye. Colour contrast thresholds were measured before, three hours after, and one week later. The authors report improvements on both colour axes, larger in the blue-yellow axis, with a residual effect still present at one week. A separate group exposed at midday showed no measurable change.
Read the paper →
12
months
of daily use
A pilot study evaluating the effects of 670 nm photobiomodulation in healthy ageing and age-related macular degeneration
A twelve-month open-label pilot in 42 adults. Two arms were followed: patients with intermediate AMD, and healthy older adults. No significant change was recorded in the AMD arm. Two measures shifted in the healthy ageing arm, which the authors note sit close to the test's own repeatability range.
Read the paper →
Laboratory studies
Conducted in animal models, where the underlying mechanism can be measured directly
1
month
daily exposure
Aging retinal function is improved by near infrared light (670 nm) that is associated with corrected mitochondrial decline
Fifteen minutes daily over one month in aged mice. Retinal electrical responses improved relative to untreated aged controls, though they did not return to the levels seen in young animals. Cytochrome c oxidase expression rose alongside the functional change.
Read the paper →
2h
effect duration
after 5 minutes
Optical monitoring of retinal respiration in real time: 670 nm light increases the redox state of mitochondria
The retina was monitored optically as it happened. After a five-minute exposure, the oxidation state of cytochrome c oxidase rose progressively, peaking around an hour later and remaining elevated for roughly two hours. A comparison exposure at 420nm produced the opposite effect.
Read the paper →
14
days
of treatment
Treatment with 670 nm light up-regulates cytochrome c oxidase expression and reduces inflammation in an age-related macular degeneration model
A genetic model matching a common AMD risk genotype. Exposed twice daily for fourteen days, cytochrome c oxidase expression increased and an inflammatory marker in Bruch's membrane fell by roughly half. Amyloid-beta deposition was unchanged.
Read the paper →
90s
per session
five sessions
Age-related retinal inflammation is reduced by 670 nm light via increased mitochondrial membrane potential
A notably small total dose. Aged mice received five ninety-second exposures across roughly thirty-five hours. Mitochondrial membrane potential rose, and markers of retinal inflammation declined relative to untreated aged animals.
Read the paper →
—
field review
not a trial
Does photobiomodulation influence ageing?
A short editorial surveying the field. It gathers findings across several species and is candid about the gaps: the mechanism remains incompletely understood, and short-lived changes in cellular energy do not on their own explain longer-term effects.
Read the paper →
One Result, Drawn Out
The 2021 Scientific Reports study is the most directly relevant human data we've found. Here is what it reported, charted from the published figures.
Chart drawn by MEINNO from figures reported in Shinhmar et al., Scientific Reports, 2021 (CC BY 4.0). The study used research-grade equipment at a specified dose in a single eye. This chart describes 670nm light in that study, not the performance of this product. A separate group exposed at midday rather than morning showed no measurable change.
Two Decades of Published Work
Most of this research comes from one group at UCL, working on the same question since the early 2000s.
Inflammation markers studied in ageing and AMD-model retinas
UCL Institute of Ophthalmology · laboratory studies
Retinal respiration monitored optically in real time
UCL Institute of Ophthalmology · laboratory study
Retinal function and mitochondrial decline in ageing mice
UCL Institute of Ophthalmology · laboratory study
The work moves into human participants
UCL Institute of Ophthalmology · human studies
Colour contrast sensitivity measured in twenty adults aged 34–70
UCL Institute of Ophthalmology · human study
The US FDA authorised the first photobiomodulation device for use in the eye
A clinical device from another manufacturer. MEINNO is not that device and is not FDA-authorised.
References
Listed in the order they appear above. Journal and institution names identify the published work being cited and do not imply endorsement.
- Shinhmar, H., Hogg, C., Neveu, M., & Jeffery, G. (2021). Weeklong improved colour contrasts sensitivity after single 670 nm exposures associated with enhanced mitochondrial function. Scientific Reports, 11, 22872. Link
- Merry, G. F., et al. (2020). A pilot study evaluating the effects of 670 nm photobiomodulation in healthy ageing and age-related macular degeneration. Journal of Clinical Medicine, 9(4), 1001. Link
- Sivapathasuntharam, C., et al. (2017). Aging retinal function is improved by near infrared light (670 nm) that is associated with corrected mitochondrial decline. Neurobiology of Aging, 52, 66–70. Link
- Kaynezhad, P., Tachtsidis, I., & Jeffery, G. (2016). Optical monitoring of retinal respiration in real time: 670 nm light increases the redox state of mitochondria. Experimental Eye Research, 152, 88–93. Link
- Begum, R., et al. (2013). Treatment with 670 nm light up-regulates cytochrome c oxidase expression and reduces inflammation in an age-related macular degeneration model. PLOS ONE, 8(2), e57828. Link
- Kokkinopoulos, I., Colman, A., Hogg, C., Heckenlively, J., & Jeffery, G. (2013). Age-related retinal inflammation is reduced by 670 nm light via increased mitochondrial membrane potential. Neurobiology of Aging, 34(2), 602–609. Link
- Mitrofanis, J., & Jeffery, G. (2018). Does photobiomodulation influence ageing? Aging, 10(9), 2224–2225. Link
Ninety Days Is the Only Evidence That Matters to You
No study can tell you whether ten minutes a day will suit your routine. Try it, and if it doesn't earn a place, send it back for a full refund.
Compare the three modelsMEINNO is a general wellness device. It is not an FDA-authorised medical device and is not intended to diagnose, treat, cure or prevent any disease, nor is it a substitute for an eye examination. Studies referenced on this page examine 670nm light in general and do not describe the performance of this product. MEINNO has no affiliation with, and is not endorsed by, any institution, journal or author named on this page.