Red light restores vision and eye health

light therapy for the eyes

One of the most common concerns with red light therapy is the eye area. People want to use red lights on the skin of the face, but are worried that bright red light pointed there may not be optimal for their eyes. Is there anything to be worried about? Can red light damage the eyes? or can it actually be very beneficial and help to heal our eyes?

Introduction

Eyes are perhaps the most vulnerable and precious parts of our bodies. Visual perception is a key part of our conscious experience, and something so integral to our day-to-day functioning. Human eyes are especially sensitive to light, being able to differentiate between up to 10 million individual colours. They can also detect light between the wavelengths of 400nm and 700nm.

visible light range
Chart showing the human eye’s perception range, within the broader electromagnetic (EM) spectrum

We do not have the hardware to perceive near infrared light (as used in infrared light therapy), just as we do not perceive other wavelengths of EM radiation such as UV, Microwaves, etc. It has recently been proven that the eye can detect a single photon.1   Like elsewhere on the body, eyes are made up of cells, specialised cells, all performing unique functions. We have rod cells to detect light intensity, cone cells to detect colour, various epithelial cells, humor producing cells, collagen producing cells, etc. Some of these cells (and tissues) are vulnerable to some types of light. All of the cells receive benefits from some other types of light. Research in the area has increased significantly in the last 10 years.

eye rods cones wavelength range
How we see light. Graph showing the wavelength perception range of the light sensitive cells in the human eye. Note that the green cones can detect light in the orange/red range.

Beneficial light for eyes

Most of the studies that point to beneficial effects use LEDs as the light source with the vast majority around the wavelength of 670nm (red). Wavelength and light type/source are not the only important factors though, as the light intensity and exposure time affect the results.

How does red light help the eyes?

Given that our eyes are the primary light-sensitive tissue in our body, one might think that the absorption of red light by our red cones has something to do with the effects seen in the research. This is not entirely the case.

mitochondria in retinal eye cells
Cells in the eye’s retina are especially abundant in mitochondria

The primary theory explaining the effects of red and near infrared light therapy, anywhere in the body, involves the interactions between light and the mitochondria. The core function of mitochondria is to produce energy for its cell – light therapy improves its ability to make energy.

The eyes of humans, and specifically the cells of the retina, have the highest metabolic requirements of any tissue in the entire body – they require a lot of energy. The only way to meet this high demand is for the cells to house many mitochondria – and so it is no surprise that cells in the eyes have the highest concentration of mitochondria anywhere in the body.

Seeing as light therapy works via interactions with the mitochondria, and the eyes have the richest source of mitochondria in the body, it is a reasonable assumption to hypothesise that the light will also have the most profound effects in the eyes compared to the rest of the body. On top of that, recent research has shown that degeneration of the eye and retina is directly linked to mitochondrial dysfunction. So a therapy that can potentially restore the mitochondria, of which there are many, in the eye is the perfect approach.

Best wavelength of light

670nm light, a deep red visible type of light, is by far the most studied for all eye conditions. Other wavelengths with positive results include 630nm, 780nm, 810nm & 830nm. Laser vs. LEDs – a note Red light from either lasers or LEDs can be used anywhere on the body, although there is one exception for lasers specifically – the eyes. Lasers are NOT suitable for light therapy of the eyes.

laser vs LED for eyes light therapy
Laser light (even if it is red) can be hazardous to the eyes. The laser beam can be focused by your eye’s lens into a tiny point of intense energy – leading to burns and scars. Red LED light doesn’t pose the same risk and so is not hazardous.

This is due to the parallel/coherent beam property of laser light, which can be focused by the lens of the eye to a tiny point. The entire beam of laser light can enter the eye and all of that energy is concentrated into an intense tiny spot on the retina, giving an extreme power density, and potentially burning/damaging after just a few seconds. LED light projects out at an angle and so does not have this issue.

Power density & dose

Red light passes through the eye with over 95% transmission. This is true for near infrared light and similar for other visible light such as blue/green/yellow. Given this high penetration of red light, the eyes only require a similar treatment modality to the skin. Studies use around 50mW/cm2 power density, with quite low doses of 10J/cm2 or less. For more information on light therapy dosing, see this post.

Harmful light for eyes

Blue, violet and UV light wavelengths (200nm-480nm) are bad for the eyes, being linked to either retinal damage or damage in the cornea, humour, lens and optical nerve. This includes direct blue light, but also blue light as part of white lights such as household/street LED bulbs or computer/phone screens. Bright white lights, especially those with a high colour temperature (3000k+), have a large percentage of blue light and are not healthy for the eyes. Sunlight, especially midday sunlight being reflected off water, also contains a high percentage of blue, leading to eye damage over time. Luckily the earth’s atmosphere filters out (scatters) blue light to some extent – a process termed ‘rayleigh scattering’ – but midday sunlight still has a lot, as does sunlight in space seen by astronauts. Water absorbs red light more so than blue light, so the reflection of sunlight off lakes/oceans/etc is just a more concentrated source of blue. It’s not just reflected sunlight that can do harm though, as ‘surfer’s eye’ is a common issue related to UV light eye damage. Hikers, hunters and other outdoorsmen can develop this. Traditional sailors such as old navy officers and pirates would almost always develop vision issues after a few years, mainly due to sea-sunlight reflections, exacerbated by the nutritional issues. Far infrared wavelengths (and just heat in general) can be harmful for the eyes, as like with other cells of the body, functional damage occurs once the cells get too warm (46°C+ / 115°F+). Workers in old furnace related jobs such as engine management and glass blowing always developed eye issues (as the heat radiating from fires/furnaces is far infrared). Laser light is potentially harmful for the eyes, as mentioned above. Something like a blue or UV laser would be the most destructive, but green, yellow, red and near infrared lasers can still potentially cause harm.

Eye conditions helped

General vision – visual acuity, Cataracts, Diabetic Retinopathy, Macular Degeneration – aka AMD or age-related macular degeration, Refractive Errors, Glaucoma, Dry Eye, floaters.

Practical applications

Using light therapy on the eyes before sun exposure (or exposure to bright white light). Daily/weekly use to prevent eye degeneration.

Summary

References

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  9. Red Light Treatment in an Axotomy Model of Neurodegeneration. Beirne et al. 2016
  10. Red light of the visual spectrum attenuates cell death in culture and retinal ganglion cell death in situ. Del Olmo-Aguado et al. 2016
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  15. Mechanistic Insights into Pathological Changes in the Diabetic Retina : Implications for Targeting Diabetic Retinopathy. Roy et al. 2016
  16. Efficacy of 670 nm Light Therapy to Protect against Photoreceptor Cell Death Is Dependent on the Severity of Damage. Chu-Tan et al. 2016
  17. Pre-exposure to low-power diode laser irradiation promotes cytoprotection in the rat retina. Sun et al. 2015
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  26. Photobiomodulation in the treatment of patients with non-center-involving diabetic macular oedema. Tang et al. 2014
  27. Low-level laser therapy improves vision in a patient with retinitis pigmentosa. Ivandic & Ivandic et al. 2014
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  29. Combining neuroprotectants in a model of retinal degeneration: no additive benefit. Di Marco et al. 2014
  30. Treatment with 670 nm light up regulates cytochrome C oxidase expression and reduces inflammation in an age-related macular degeneration model. Begum et al. 2013
  31. The time course of action of two neuroprotectants, dietary saffron and photobiomodulation, assessed in the rat retina. Marco et al. 2013
  32. Paranode Abnormalities and Oxidative Stress in Optic Nerve Vulnerable to Secondary Degeneration: Modulation by 670 nm Light Treatment. Szymanski et al. 2013
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  40. Treatment with 670-nm light protects the cone photoreceptors from white light-induced degeneration. Albarracin & Valter et al. 2012
  41. Photobiomodulation in Inherited Retinal Degeneration. Gopalakrishnan S et al. 2012
  42. Low-level laser therapy improves visual acuity in adolescent and adult patients with amblyopia. Ivandic et al. 2012
  43. 670-nm light treatment reduces complement propagation following retinal degeneration. Rutar et al. 2012.
  44. 670 nm red light preconditioning supports Müller cell function: evidence from the white light-induced damage model in the rat retina. Albarracin R et al. 2012
  45. Photobiomodulation protects the retina from light-induced photoreceptor degeneration. Albarracin et al. 2011
  46. “He-Ne low level laser therapeutic applications for treatment of corneal trauma [Proceedings article]Koev et al. 2011″
  47. The influence of He-Ne laser on scar formation after trabeculectomy in rabbits. Hu et al. 2010
  48. Near-infrared light protect the photoreceptor from light-induced damage in rats. Qu et al. 2010
  49. Near infrared light reduces oxidative stress and preserves function in CNS tissue vulnerable to secondary degeneration following partial transection of the optic nerve. Fitzgerald et al. 2010
  50. Influence and mechanism of He-Ne laser on scar formation of filtration canal after trabeculectomy in rabbit. Wang et al. 2010
  51. He-Ne low level laser therapeutic applications for treatment of acute iridocyclitis. Koev et al. 2010
  52. Gene and noncoding RNA regulation underlying photoreceptor protection: microarray study of dietary antioxidant saffron and photobiomodulation in rat retina. Natoli et al. 2010
  53. Early diagnosis of ocular hypertension using a low-intensity laser irradiation test. Ivandic et al. 2009
  54. “[Effect of infrared low-intensity laser therapy on orbital blood circulation in children with progressive short sightedness]. [Article in Russian]Shurygina & Khadzhieva et al. 2009″
  55. Neuroprotective effects of near-infrared light in an in vivo model of mitochondrial optic neuropathy. Rojas et al. 2008
  56. Low-level laser therapy improves vision in patients with age-related macular degeneration. Ivandic et al. 2008
  57. GaAs laser treatment of bilateral eyelid ptosis due to complication of botulinum toxin type A injection. Majlesi G et al. 2008
  58. Increases in central retinal artery blood flow in humans following carotid artery and stellate ganglion irradiation with 0.6 to 1.6 microm irradiation. Mii et al. 2007
  59. Therapeutic photobiomodulation for methanol-induced retinal toxicity. Eells et al. 2003.
  60. “[Effects of low-intensity infrared laser irradiation on the eye (an experimental study)]. [Article in Russian]Prokof’eva et al. 1996″
  61. Ophthalmic effects of low-energy laser irradiation. Belkin & Schwartz et al. 1994
  62. Dose and temporal parameters in delaying injured optic nerve degeneration by low-energy laser irradiation. Rosner et al. 1993
  63. Low-energy laser irradiation–a new measure for suppression of arachidonic acid metabolism in the optic nerve. Naveh et al. 1990
  64. “[The stimulating effect of helium-neon laser radiation on rabbit eyes]. [Article in Russian]Sokolovskii et al. 1990″
  65. “[Laser irradiation: study of general and local mechanisms of its action in irradiation of the eyeball. An experimental study.]. [Article in Russian] Kiselev et al. 1990″
  66. Temporal parameters of low energy laser irradiation for optimal delay of post-traumatic degeneration of rat optic nerve. Assia et al. 1989
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30 thoughts on “Red light restores vision and eye health

  1. Mike says:

    Thanks for a great post! For the studies using 670nm red light, do they assume eyes open or eyes closed?

    I’ve been using full body red light therapy 50mw/cm2 for 20 minutes eyes closed but I’m guessing my eyes won’t get a sufficient dosage unless my eyes are open. Do the studies say anything about this?

    • Joe says:

      A lot of the studies have eyes opened, but eyes closed is studied too.
      Eyes closed actually makes more sense to me. The eyelid is a thin piece of tissue, fairly penetrable to red light. As the light passes through the eyelid tissue, it scatters, giving a much more even spread throughout the entire eyeball.

      • Ali says:

        Hello Joe, I found a study by Professor Glen Jeffery (UCL Institute of Ophthalmology) College of London, the specs of the light they used were 10 670nm LED mounted behind a light diffuser embedded in a tube that was 4cm in diameter with Energy of 40mW/cm2. Do you sell such device? Greatly appreciate any guidance

    • nimhathuna.g says:

      Hi, Joe, this is a super blog you seem very informed. how near should you have red light therapy on your fae,should you make contact with skin

  2. Mary says:

    I am wondering if any studies are in the works for the application of red and near-infrared light to any other retinal diseases, such as gene-mediated retinopathies. It seems that if red light in these wavelengths strengthens the retinal cells’ own defenses by recharging the mitochondria then the beneficial effect might work with any number of other retinal diseases.

    • Joe says:

      There will be upcoming studies, yes. It is a very active field, especially in the last few years. They’re not so easy to find, but you can get the good ones by starting on a Google search and when you find a relevant study, look at all of the references within that study.
      Your extrapolation about uses on various other retinal diseases does make sense.

  3. Martin Z says:

    I own an LED pad that is made to be held over the body or wrapped around affected body part. It has 50 Infrared LEDs @880nm wavelength, approximately 100 mw output each diode and 40 Visible Red LEDs @650nm wavelength, approximately 50mw output each diode, totally 5200 mw (approximately) output/
    Power density – approx. 100mW per square cm
    I use it on my jaw for 30 minutes daily and worry about potential eye overexposure. WHat do you think?

    • Joe says:

      You can’t calculate power density like that. For several reasons it has to be measured, not calculated.
      50mW/100mW rated LEDs are extremely weak, far too weak for light therapy. You would just about get 100mW/cm2 power density at point blank range with 1000mW rated LEDs. The power density of your type of LEDs would be perhaps 5mW/cm2 max.
      Regardless, no, don’t worry about eye issues. You can find concerns about light being maybe harmful for the eyes online, but it basically comes down to whether you are heating the eyes or not. It is the same thing as with your skin. Once the skin gets warm/hot, it is not beneficial anymore. The same applies for the eyes. Otherwise there is no harm specific to the eyes from light therapy. It is good for the eyes in the same way it is good for the rest of the body. You can’t improve one part of the body but harm the eyes at the same time – they would both be improved.

  4. Sanjay Chandel says:

    I am a bit confused about how much J/cm2 is needed for treatment of AMD if I get a unit giving 100mw/ cm2 at 10cm. Studies says 4 doses of 0.3 J/ cm2 were given 4 times ( twice a week) totalling 1.2J/ cm2 for the great results. That seems very low. I can get that much dose in 12 seconds using my unit then in just one session. That means if I do that every day, I am overdoing it and it could do unwanted damage?

  5. JT says:

    Hi. Can you give more information re: cataracts? I noted the listing under “Eye conditions helped.” Specifically, cortical cataracts, which wavelength to use, and recommended course of therapy.

  6. Charlie H says:

    I s there such a thing as red light eyeglasses for Macular Degeneration for sale on the market, if so where can I find them? Thank You, Charlie

  7. Liz says:

    Very interesting

    As you mentioned in the comments that LOW intensity light would be be better for eye use – what is the lowest intensity device ( and the item #) that I can purchase from your site?
    Thank you !

  8. Alan Marsh says:

    As far as the products you carry are concerned, do you recommend the Red Light Device Mini for treating eye/vision or the Red light device? Also, do these products have specific instructions for using either of them to treat vision/eyes?
    I want to thank you for the incredible effort you have put into educating us. The concern for being accurate is very apparent and much appreciated. I would have 100% confidence that your products perform as advertised. Thank you for the feedback.

  9. Charles Bliss says:

    Where can you purchase the LED flashlight that is mentioned in this article? My searches are turning up nothing. Thanks

  10. Rob says:

    Where can I buy a 670nm true red light source? I read that special 670nm true red flashlights were used in a study but all of the flashlights I’ve looked at online don’t give the nm value of the red light source.

  11. Woody says:

    Just received your 670 Device. I ordered it for eye therapy. It’s bright. At what distance from eye to device and at what usage frequency would you suggest. Compliments on a very well made device and prompt service. Thank you.

    • Joe says:

      Thanks Woody, I use it at about 25-30cm from my eyes. So almost 12 inches. I use it several times a day for short 30 second sessions whenever I’m working with my eyes (screens/tv/phones/etc). If I only did it once a day, it would be 2-3 minutes total.

  12. Lesley Leigh says:

    I have found a cree astronomy torch with a 630nm red light, would this be safe to use on the eyes

  13. Nancy says:

    We are all looking for that flashlight and I believe it was specially made for the study. Looks like an ordinary maglite with a 670 nm LED attached to it.

  14. Matt Lo says:

    Without a quality source for specific 660-670nm red light, how about using a 670nm bandpass filter and any standard visible light source? Bandpass filters are very specific to frequency.

  15. John says:

    I have also failed to find the the 679’m torch mentioned in the study. Can anyone say clearly where it can be purchased

  16. John Mills says:

    Hi Joe. Hope all is going well across the pond. Your’e the only game in town who certifies the frequency output of the devices offered. I’m looking to pick up a few more for eye health for myself, mother and a few friends.

    This research has been making the rounds for the last few months or so. Pretty much the same story repeated:
    “The second eyesight-saving strategy is to stare into a red light every day.
    A small LED torch with a deep red beam will do the job, say researchers from University College London. Staring at it for three minutes every day can reverse eyesight that has started to deteriorate, a problem common among the over-40s.

    Our vision’s colour contrast can improve by 20 percent by doing the exercise for even just a few weeks, the researchers discovered when they tested the technique on a group of 24 people, aged between 24 and 72 years.

    The longwave light reboots the retina’s cells, which age faster than cells in any other part of the body. Over time, there can be a 70 percent reduction in the cells’ capabilities which causes a significant decline in the eyes’ photoreceptor functions.

    The torches used for the experiments retail for around £12 ($15).”

    Question: Which device? It appears the research only used 670nm. Probably the safest bet to stick with that frequency. Now which one? The lower powered 36w Red Mini 670 or the higher penetration 126w Red 670 Device? Distance from each device and treatment times would be nice to know. Also…the study suggests a “flashlight” type device you stare into. I’m assuming this prevents light from spreading out. I’m guessing the 126w Red 670 Device is way to powerful. I’ve got a few RLM products but unfortunately they also output in the 830nm range. Some mouse testicle studies showed cell abnormalities with exposure to this frequency.

  17. Jennifer says:

    Because it looks like many people here are interested in self-administered light therapy for the eyes, since I’ve been doing it for over a year, just thought I’d share my experience. I have a 16.7 watt handheld “floodlight” style 670 nm LED bulb. When I do treatments, I do one eye at a time. I have a piece of cardboard cut so I can hold up the light and position it 10″ in front of the eye. Then I turn on the light, and cover my other eye with my hand while I’m treating the one eye. I keep the eye closed; trust me, plenty of the light gets through. I count off to 90 (or set my iPhone timer for 2 minutes) to get a 2 minute dose. For the light I’m using and the distance from the eye, this comes out to a dosage of around 4 – 5 joules.

    Now, my experience: No side effects, other than that your color vision will be off for several minutes after you complete the treatment (you’ve really saturated the red cones and everything will look bluish green for a little while). I wouldn’t recommend doing the treatment with your eyes open; closed lids are much more comfortable and you’re going to get 95% of the dosage you’d get with your eye open anyway. I saw some improvement in the first month in clarity and color discernment in the affected eye and since then, have noticed no further visual deterioration.

    My condition is more serious; I have wet macular degeneration which had its onset in April 2018 with a burst blood vessel leading to central serous retinopathy (I had a big fluid bubble under the center of the macula). This was initially resolved with anti-VEGF injections, but after that, I started to develop new, abnormal leaky vessels in the macular area, I suspect due to cell death and stress from the fluid bubble preventing cells from getting oxygen and nutrients. I can see where the vessels are leaking because in bright light, it looks like glitter or shimmering. I had my last injection in I think September of last year, about 6 weeks after I started doing the light therapy; I simply couldn’t afford to go back until I got insurance coverage, and then once I got that, before I could get back to the retinologist, COVID shut everything down. So I know that since last September, I have continued to have leaking – but I have not had a further perceptible deterioration in the vision in that eye. My calculus is that, fluid buildup under the retina places strain on RPE cells; the near-infrared treatment gives these cells the ability to survive the stress.

    The bad news is that 670 nm does not seem to prevent the abnormal vessels from growing; I had hoped that it might downregulate VEGF production and so suppress their growth. It actually might discourage them, since at least one small study noted a reduction in exudate in patients with diabetic macular edema who used NIR therapy, but it doesn’t suppress them from growing entirely. I am going to start treating as well with a 590 nm light, since the LumiThera device currently in clinical studies includes this wavelength and there are indications that 590 nm IS effective in downregulating VEGF. So we shall see.

    My takeaways is: a daily dose of 4 – 5 joules of 670 nm light through a closed eyelid is completely safe. You will not injure your eyes, and you will more likely see some improvement in clarity and color. But really – close your eyes. It won’t substantially affect the dosage you get to the retina, and if you don’t, you’re going to be seeing red dots for 20 minutes after you treat!

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