How did the clumsy boxes for experimental light treatment from the eighties developed into high-tech glasses for top athletes? And what is coming next? “I am confident that light glasses can help every patient with Parkinson’s disease who also suffers with sleep problems, but we still want to wait for the results of an ongoing clinical trial before we start advertising it,” says Toine Schoutens, a pioneer of light therapy and CEO of a team developing new glasses helping with jet lags, sports performance, sleep and depression.

History of bright light therapy: from winter blues to Olympic games

I wanted to introduce you by asking whether you are more of a researcher or a business manager – but then I realized that before developing light therapy glasses, you spent many years working as a psychiatric nurse. What made you switch from nursing to running companies?              

That’s a very long story! Indeed, I am a psychiatric nurse. In the late eighties, I was asked by the hospital where I was working to investigate light therapy for winter depression. In that time, it was very new, and we did not know much about it, so I went to a library and read everything available. With our team, we did an effect study on people sent by their house doctors with winter depression symptoms. For the first time, we were treating them with a light therapy unit. There was no control group that time, but most of the people recovered, which was enough for the hospital to establish one of the first light therapy polyclinics in the Netherlands.

It was a big success – and afterwards I started opening similar centres in other clinics across the Netherlands and Belgium. I was working in many hospitals, I opened the first company for the light therapy in the Netherlands. Then Philips approached me, and I started helping them with the development of the first therapy lightbox. In the meantime, I was working at the Light & Health Research Foundation based at Eindhoven University of Technology. In the end, I was rather a researcher and partly a businessman than a nurse. Finally, I was delivering up to two hundred and ten shops for Philips, which was a great success – which, however, pushed me out of business, because their started selling it in regular electro shops, while I was only responsible for specialised health centres.

In the meantime, I became involved in sports. The Dutch Olympic team asked me to help them to overcome jet lag before the 2008 games in China, so we started a feasibility study using light therapy for fighting jet lag in Olympic swimming team.

The effect was very high – mostly because their compliance was high. As you probably understand, the athletes do exactly what you ask them to. When they are supposed to go to bed and wake up every day an hour earlier and apply morning lights and evening darkness, they do so. As a result of this treatment, the twenty swimmers had no jet lag arriving to China, which was a remarkable result. Following that, it was judo, gymnastics, athletics and so on and so on. In Vancouver, we were with ice skating… Only in 2012 in London, there was nothing for us to do, if you know what I mean.

Sure, flight from the Netherlands to London takes like an hour and half, so you hardly need to deal with a jet lag. But just to make things clear about the athletes: I suppose you were measuring their circadian rhythm affected by jet lag, not directly their performance, am I correct?

Omar McLeod with Propeaq Lightglasses

Yes. But you surely understand that when you have jet lag, you cannot perform very well. Also, there is a peak performance moment for every athlete, at the end of the afternoon. This is when they are able to perform the best.

Anyway, in 2007, a student and I developed the first prototype of light glasses: primitive, almost prehistoric glasses that we put it in the fridge that time. And then after the London Olympic Games, I was working with Jacco Verhaeren technical director of the Australian swimming team. And he came to me afterwards, saying that those light boxes are big, clumsy and not easy to travel with. Do you have something else, easier to use to beat jet lag and improve the peak performance moment?

I took those light glasses and developed them into the prototype of what we now call Propeaq. In 2016, we tested them with several athletes, working on jet lag as well as peak performance. Most swimmers perform best at about five or six in the afternoon, but not at 11pm. This was our first trial to shift sleep to a later moment.

You can shift sleep easily by up to 1.5 hours per day. Currently, we have over 600 athletes from 14 countries using our light glasses for beating jet lag and shifting their sleep rhythm to be able to perform at any moment of the day.

Wow, so that is how those early light boxes for beating winter depression transformed into the designed glasses you are selling today. Are they made primarily for athletes?

Most people use the glasses to shift their sleep rhythm when working nightshifts, to stay awake more easily when working at night and sleep better during the day. That is the main purpose. There are also people with winter blues, a mild form of winter depression. They use the glasses so as not to feel tired during winter. And of course, people fighting jet lag. And the athletes.


Propeaq: blue lamps and red lenses in one package

The glasses consist of two parts: red lenses filtering out the blue part of the spectrum for evening protection and the little built in LED therapy lamps for morning refreshment…

Yes, those are the blue LED lights built within the frame, with very low intensity, some 35 lux. But quite close to the eye. The wavelength is 468 nanometers and density 0,9μW  per square centimetre. Very low dose of light to be used for maximum thirty minutes a day.

The main wavelength for shifting sleep break and suppressing melatonin is the blue part of the spectrum. So, you don’t need a lot of white light with all colors involved, but only the blue part of the spectrum. Then you can only use such a small intensity for the same effect.

On the other hand, it is hard to compare then to the usual recommended dosage of 10,000 lux of white light in the case of light boxes.

You can compare it. The amount of blue in the sunlight is much higher, of course, but you don’t stare into the sun. So, our 35 lux means that you can totally suppress melatonin in 30 minutes. When you use the light at 2 o’clock at night, for example, melatonin would be normally high. But using the glasses for 15 minutes, melatonin is suppressed almost by 100%.


Not sure what 35 lux is, why wavelength matters or what melatonin is? Check our explanations!

Illuminance describes quantity of light reaching our eyes (or any other surface). The unit of illuminance is one lux.

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Scientific experiments gradually revealed that in humans, melanopsin is most responsive to light with wavelength of 479 nm.

The sun clock in our brains: from light to neurotransmiters

The key molecule of this system is called melatonin: a hormone putting our brain to sleepy state which is only produced when we are not exposed to light.

How does the brain know when to fall asleep? Sleep regulation for dummies.

That is the first part of your glasses, the LEDs that block melatonin production. Then there is the second, complementary part – the red lenses filtering blue light when you, on the other hand, want to prepare for sleep. What percentage of the blue light can they filter out?

With the standard equipment we use now, everything in the blue and blue-green part of the spectrum is blocked. It completely blocks blue and blue-green light. In a new model we are launching in December 2019, we are using amber glass instead of red, and those only filter blue out, but not the blue-green. Everything above 480 nm which does not affect melatonin that much, will be left unfiltered. The new lenses are easier to use, because the visibility is better.

You mentioned the launch of new glasses in December 2019. What is going to change compared to the current model?

 In December, we will launch the model 1.0B. The glasses are the same but in this first model, we had a Bluetooth connection which did not offer real advantage to the user, so it will not be there anymore. Plus, the first model included adapters for many different countries, but most people use USB, so we only include USB cable now. Therefore, we have the same device, but easier to use and with a little bit lower cost.


Ongoing development: from increasing compliance to improving Parkinson’s

We have witnessed many hypes in psychology and neuroscience lately. Some novel treatments were found to be less efficient than what was originally expected. Bright light therapy is based on a limited number of properly blinded and controlled trials. Is there a risk that in a decade or two, we will realize that our current hopes are exaggerated once again, and that the light therapy is actually not powerful enough for meaningful clinical use?

That is possible. But the highest problem is compliance. When people buy a lightbox, they mostly sit in front of it for two or three days – and then it disappears into a cupboard. People are not willing to spend half an hour of their morning sitting in front of a lightbox. A study, which is quite old, found compliance to be around 15%.

There will be kind of saturation, I think. It always happens, with all kind of new treatments or devices. But the science behind light therapy and shifting wake rhythm is very robust. I think the glasses are the first new development making it easier to use light therapy for people with seasonal affective disorder or shift work.

But it is always their behaviour that is most important: people are generally lazy. For example, we thought that jet lag is a big problem. And it is. But people think: I have to deal with jet lag, so be it. In theory, we can beat jet lag up to 100%. And most elite athletes going after gold medal would use it. But business travellers don’t.

When you fly from Amsterdam to Tokyo, for example, there is eight hours of time difference. Using this technique, you have to go to bed an hour and half earlier for five days and use the blue light. And most people just think: not me! In the end, we offer a 50-60% success rate when starting three days before the flight and two or three days after the flight, which makes people more satisfied.

Besides the well-researched sleep problems and depression, there are tens of ongoing studies on novel applications of light therapy, including, for example, Parkinson’s, various dementias or obesity. Do you think we prove light therapy effective for these disorders in the future as well?

Yeah, I’m quite sure about Parkinson’s disease. People suffer a lot from this terrible disease and most of the time they have sleep wake problems, because they sleep during the daytime. Short naps, sometimes once or twice, though mostly three, four or even five naps during the day. That lowers their sleep pressure in the evening, with the result of not being able to sleep very well at night.

In the first patient study, which was a cohort study, we gave the patients 30 mins of blue light in the morning and 30 mins in the beginning of the evening. Their photo period was longer. And we asked them not to sleep more than once during the daytime. One 20 minutes long power nap was OK, but not more. And they felt higher sleep pressure during the night, slept better, felt a little bit better and there were some motor improvements. And that was enough to start the second study we are conducting right now.

The current, placebo-controlled study is not being done by us but by Nijmegen (Radboud) University, by professor Bloem and his colleagues. We expect improvement of sleep, mood and some motor symptoms: mainly dyskinesia, a kind of tremor accompanied by shaking.

And based on the previous study and your experience, what percentage of the patients do you expect to really feel the improvement? Personally, I am sure there will be some statistical effect, but I can imagine that for many people, it might be too subtle to notice…

That is not quite clear. We are planning a further, clinical study to find out at which stage of the disease blue light has the best effect, whether there are some age or gender differences… That is what we want to find out in the next two years. I think it will have an effect on all people with Parkinson’s disease who are suffering from sleep disorders as well, what we call comorbidity. I am quite sure that we will make clear that people suffering from Parkinson’s disease and sleep-wake disturbances will benefit from this new technique.

And do you think the effect will be strong enough for each single of them to notice the difference?

I don’t know, but the ongoing trial will show us within the next several months. Our team is just finishing collection of the data and they will start analysing within the next six or eight weeks.

Of course, I am only involved as a technician in these studies, I do not measure the people. Some are measured in the Netherlands, some in Poland by doctor Smilowska. We are only involved as technical support. And we are not selling to those suffering from Parkinson’s at the moment. They can still buy if they really want to, but we are not promoting it until the third clinical trial has announced its results.

I can’t wait for the results! And the last question: You also promote light therapy in dermatology. That is behind the scope of this website but still, could you quickly sum up other use of light therapy than in psychiatry, and compare the evidence we have in mood or sleep disorders and in skin problems?

That is quite different. Phototherapy with ultraviolet light is being used for almost sixty years now, for psoriasis, vitiligo and acne and so on. In this case, we are just a reseller of Medisun Lighttherapy in the Netherlands, selling to hospitals or to patients in case they can use it at home. But they are always guided by a dermatologist.


Antonius SCHOUTENS, founder and CEO of Chrono Eyewear B.V., producer of the Propeaq glasses. As a nurse, Toine discovered the effects of light on human performance and our biological clock. He then became one of the first pioneers for the use of light for treating the winter blues. The core of his work is in portable light therapy. “Sitting in front of a light box every day is not an efficient use of your valuable time,” says Toine, summing up his mission.