Could Indigo Light Therapy Offer A New Myopia Control Treatment?
A fascinating new animal study suggests that a narrow band of indigo light, commonly lacking from indoor lighting, may influence how the eye grows. It is exciting science, but it is not yet a treatment for children.
Indigo Light Therapy, is not 'a thing' yet, but could it offer a new treatment for progressive myopia? It's a thought that made me stop and say: ‘Oh, that’s interesting’.
At Myopia Focus, we keep a close eye on the latest myopia news, developments and research. Not every study is an immediate breakthrough or gives parents something new to act on, but it can still be interesting and important. Sometimes, as with this research, it helps to reinforce a practical message that parents can act on today.
And this really is an interesting one. Scientists found that adding a particular band of indigo light to ordinary warm-white LED lighting completely prevented a severe form of experimentally induced myopia in juvenile tree shrews. That is a striking result, published in Cell Reports Medicine, and it may help us understand something important about the difference between daylight and the artificial light under which children spend so much of their time.
First, why does this matter?
Myopia, or short-sightedness, is becoming increasingly common in children around the world. It is easy to think of it as little more than blurred distance vision, followed by a pair of glasses. But myopia usually develops because the eye has grown too long, and higher levels of myopia are associated with a greater lifetime risk of serious eye conditions, including retinal detachment, myopic maculopathy and glaucoma.
The good news is that clever scientists are approaching the problem from many directions. Some are creating spectacle and contact lenses designed to slow eye growth. Others are studying low-dose atropine, improving how progression is measured, trying to identify which children are most at risk, or looking for ways to prevent myopia before it begins.
Think of it as a very large jigsaw puzzle. We are unlikely to find one miraculous final piece labelled ‘the cure’. Instead, each good study adds another piece: how the eye detects light, how it knows when to grow, why time outdoors appears protective and how modern indoor life may be changing the signals received by a developing eye.
So, what did the researchers find?
Researchers from the University of Alabama at Birmingham and Cincinnati Children’s studied juvenile tree shrews. In one eye, they placed a strong minus lens designed to push that eye towards myopia. The animals then lived under warm-white LED light, with different groups receiving additional short-wavelength light.
Under the warm-white LED lighting alone, the lens-wearing eye became highly myopic. When the researchers added the most effective indigo wavelengths, between 419 and 446 nanometres, the induced myopia was completely suppressed. The final refraction was approximately +0.4 dioptres with the indigo supplementation, compared with -11.6 dioptres under the warm-white LEDs alone. Crucially, the excessive lengthening of the eye was also prevented.
For Dr Emily J. Patterson, Senior Vision Scientist , the particularly interesting point is not simply that indigo light worked, but how narrow the effective window appeared to be. Protection changed sharply across the wavelengths tested, moving from partial suppression with violet and blue light to near-complete suppression only in the 419-446 nanometre indigo band. In other words, this is a much more specific story than simply saying ‘more light helps’. It points towards something particular within daylight’s spectrum.
Those numbers are dramatic, but context matters. A tree shrew study is a little like testing a promising technology on a controlled test track. It can reveal whether an idea works biologically and whether it deserves to move forward, but it is not the same as putting it onto busy roads in the real world. These animals were not children, and this was not naturally developing childhood myopia. One eye was deliberately exposed to a very powerful myopia-inducing lens.
You can read the full published article in Cell Reports Medicine.
How can white light be ‘missing’ a colour?
This is where the study becomes particularly interesting. We tend to treat white light as though it is one thing. It is not. White light is more like a recipe: different mixtures of wavelengths can produce something that looks broadly white to us, just as different ingredients can create cakes that look similar from the outside.
Daylight is extremely bright and contains a broad mixture of wavelengths. An indoor LED may also look white, but its recipe can be very different. Warm-white LEDs commonly have a strong blue-region peak combined with broader output at longer wavelengths, while providing relatively little light in the particular 419-446 nanometre indigo band highlighted by this study.
So perhaps indoor light is not only much dimmer than daylight. Perhaps it is also leaving out a biological ingredient that a growing eye expects to receive. That is the hypothesis. It is an intriguing one, but at this stage it remains a hypothesis rather than a proven explanation for the global rise in childhood myopia.
Emily sees a direct connection with the Mynamics project, which is investigating the specific environmental and visual factors that drive eye growth. If the spectral composition of light matters independently of brightness, it is exactly the sort of detail that could help us move from broad associations towards a more precise understanding of why myopia develops.
The eye does more with light than create a picture
Most of us learnt that rods and cones are the eye’s light receptors. They allow us to see, but they are not the entire story. The retina also contains other light-sensitive proteins, called opsins, which can trigger biological responses without creating part of the picture we consciously see.
A useful comparison is a smoke detector. Its job is not to show us an image of smoke; it is to detect a signal and set another process in motion. In a similar way, these non-visual light pathways may help regulate processes such as daily body rhythms and, potentially, the growth of the eye.
One candidate is opsin 5, or OPN5, also known as neuropsin. Earlier mouse studies suggested that violet light could prevent induced myopia and that OPN5 was needed for this effect. But there was a problem: the very short wavelengths used in mice are largely filtered out by the lenses of tree shrews and humans before they can reach the retina.
The new study tried to bridge that gap. It suggests that slightly longer indigo wavelengths can pass through a more human-like lens while still stimulating the relevant pathway. The authors also propose a new ‘µ-opic’ measure to describe how biologically effective a light spectrum may be for myopia suppression after the filtering effect of the eye’s lens is taken into account.
Chun Lin Yap, Technical Research Fellow at Occuity, cautions that the study did not test the OPN5 mechanism directly. It therefore remains unclear whether OPN5 itself produced the protective effect in the tree shrews. Emily agrees that the evidence is correlational rather than causal: the researchers confirmed OPN5 expression in tree shrew retinal ganglion cells, measured its absorption spectrum and found that an ‘effective’ OPN5 absorption curve, adjusted for lens filtering, closely followed the wavelength-dependent suppression they observed.
That makes OPN5 a credible candidate, but it does not close the case. The relevant spectrum is broad enough that other opsins, including OPN3 and OPN4, and the short-wavelength cone opsin OPN1SW cannot be ruled out. Dopamine, circadian timing, conventional photoreceptors and other retinal pathways may also be involved. As Chun suggests, future research may reveal whether particular opsins can eventually be targeted to prevent myopia or slow its progression. For now, the eye appears to be responding to a network of signals rather than one simple switch.
Could modern LEDs be part of the myopia story?
The paper raises a much bigger question. Human eyes evolved in daylight, yet many children now spend most of their waking day in classrooms and homes under artificial light. Two rooms can appear equally well lit to us while delivering quite different spectral signals to the retina.
Could the move indoors, combined with lighting that contains relatively little indigo, be one contributor to the myopia boom? Possibly. But myopia is not a detective story with a single culprit. Genetics, intensive education, prolonged near work, reduced outdoor time, urban living and the interactions between them all matter. Indigo light may prove to be an important missing clue, but this study cannot tell us how large a role it plays in children.
Please don’t rush out and buy an indigo lamp
This is the most important caveat for parents. We do not yet know whether indigo-enriched lighting prevents myopia in children. We also do not know the right wavelength profile, intensity, dose, timing or duration, or whether long-term use would be safe, comfortable and acceptable in homes and classrooms.
A product labelled ‘indigo’ or ‘full spectrum’ should not be assumed to reproduce the researchers’ experimental light, let alone its biological effect. ‘Contains indigo light’ would be rather like saying a medicine contains the right ingredient without knowing the dose, formulation or whether it has ever been tested in people.
Do not wait for the next magic treatment
It is natural to be attracted to the next clever lens, eye drop, lamp or device. Science moves forward because researchers test new ideas, and this one certainly deserves proper human research. But parents do not need to wait for that research before acting on the things they can influence today.
We already have strong evidence that more time outdoors helps reduce the risk of children becoming myopic. We also have good reasons to avoid very long, uninterrupted periods of close work, to encourage sensible viewing distances and regular breaks, and to manage recreational screen time, particularly where it replaces outdoor activity.
In practical terms: make outdoor time part of the normal day, break up reading, homework and screen use, discourage children from holding books or devices unnecessarily close, and arrange regular eye examinations. Many professional recommendations suggest aiming for around two hours outdoors each day where practical, alongside normal sun-safety guidance.
If your child is already myopic, speak to an eye care practitioner about active myopia management. Depending on the individual child and local availability, this may include specialist myopia-control spectacles, dual-focus or multifocal contact lenses, orthokeratology or low-dose atropine. An interesting future lighting intervention should not delay a management plan supported by evidence today.
What should practitioners take from it?
For practitioners, the paper pushes the discussion of light beyond a simple indoor-versus-outdoor lux comparison. Spectral power distribution, the wavelengths transmitted through the ocular media and the biological sensitivity of individual retinal pathways may all matter. If the result translates to humans, ordinary photopic illuminance alone will not adequately describe a lighting intervention.
The finding is also strengthened by the fact that the researchers assessed both refraction and ocular dimensions. Preventing excessive axial elongation is more clinically meaningful than producing a temporary refractive shift alone.
However, the translational limits are considerable. Lens-induced myopia is artificial and unusually strong. Tree shrews are a valuable, near-primate model for refractive development, but they are not children. The study does not establish efficacy for natural myopia onset or progression, identify a clinically useful exposure, show how lighting might interact with existing treatments, or establish long-term ocular and circadian safety.
The questions that now need answering
Does it work in children? Human trials must show whether indigo-enriched lighting reduces new cases of myopia or slows axial growth compared with standard lighting.
Prevention, progression or both? The evidence for outdoor time is strongest for delaying onset. Children who are not yet myopic and those with established myopia need to be studied separately.
What is the dose? Researchers need to define wavelength, retinal irradiance, daily exposure, timing and the minimum effective dose.
Is it safe and acceptable? Long-term ocular safety, glare, colour rendering, comfort, sleep and circadian effects all need proper assessment.
How does it work with existing management? Any additional benefit alongside spectacles, contact lenses, orthokeratology or atropine must be tested rather than assumed.
Our take: genuinely exciting, but the practical message is familiar
The appeal of this idea is obvious. If the right indoor light could help guide a child’s eyes towards normal growth, it could eventually become part of classrooms, nurseries and homes. It would work quietly in the background rather than relying on every child remembering a treatment.
But we are not there yet. The honest headline is not ‘indigo light prevents myopia in children’. It is that indigo light completely prevented a severe form of experimentally induced myopia in a promising animal model. That is enough to make us say, ‘Oh, this is interesting’, and enough to justify urgent, independent human research. It is not enough to support treatment claims.
For now, outdoor daylight remains the practical lighting intervention supported by human evidence. Perhaps future research will show that one part of its protective effect comes from wavelengths our indoor lights have been leaving out. In the meantime, the study reinforces a simpler point: the visual environment in which children grow up matters, and there are useful changes families can make now.
Expert commentary
This article incorporates comments from Dr Emily J. Patterson, Retinal Imaging Scientist, and Chun Lin Yap, Technical Research Fellow. Their observations have been attributed throughout.
An important disclosure
The paper states that Rafael Grytz and Richard Lang are named inventors on pending patents for lighting devices related to this research. Grytz is also the founder and chief scientific officer of Electric Indigo, a University of Alabama at Birmingham start-up in which the university has an ownership interest. These declared interests do not negate the peer-reviewed findings, but they are relevant context when considering future commercial claims and underline the importance of independent replication and human clinical evidence.
Published research
Rafael Grytz, Mustapha El Hamdaoui, Takahiro Yamashita and colleagues. Prevention of myopia in a near-primate by supplemental indigo light suggests a hypothesis for the myopia boom. Cell Reports Medicine, published online 18 August 2026. View the full published article | DOI: 10.1016/j.xcrm.2026.102999
Comments