Resources | Tech-Talks Bregenz | Health & Environment | Medical | Jul 29, 2019

Tech-Talks BREGENZ - Dr. Octavio Perez, Adjunctant Researcher, Mt. Sinai Hospital

Dr. Perez received the LED professional Scientific Award 2018 for his paper on "Light and ED Clinical Wellness and Performance Improvement", which was published in LpR 70. The evaluation jury had the following to say about why they selected his paper: "The paper is based on the clear definition of the research question, hypothesis and objective of the research. The methodology of the screening study is described in detail and both subjective and objective parameters have been measured. Although Emergency Department lighting is a very special application, the paper provides interesting results." This interview provides background information on Octavio Perez, his work in general, his opinion on human centric lighting risks, opportunities and applications and how he became involved in this interesting research topic. Dr. Perez also provides additional details about the presented paper.

LED professional: Thank you very much for coming here to talk to us. We'd also like to congratulate you again for winning the award for the best scientific paper in 2018.

To start off, maybe you could tell our readers a little about you, your work, and the paper that won the award.

Octavio Perez: The paper that was selected as winner of the award was related to my doctorate research that was conducted at Mt. Sinai hospital in New York City in the emergency department simulation center. Now, after finishing my PhD, I'm an adjunct researcher. What we mainly do is look for funding opportunities to set up research in order to provide more evidence, especially in the patient rooms, so that we can improve the patients' length of stay and healing, using light.

LED professional: What exactly did you study?

Octavio Perez: I studied mechanical engineering – a long time ago! I moved around in different businesses, and then in 2011 I was involved in a very interesting lighting project and then I was invited to go back to university part time, by the Queensland University of Technology to begin my Master's in lighting. They asked me to go to Mount Sinai to do my doctorate research because it was a new field and we needed to do the work there. Also, Mount Sinai got the funding from the NIH – The National Institute of Health – and this was great because it meant we were getting the money from the top U.S. agency for health.

LED professional: Is your work in the emergency department a central topic for you or does it cover other topics?

LED professional: Thank you very much for coming here to talk to us. We'd also like to congratulate you again for winning the award for the best scientific paper in 2018.  To start off, maybe you could tell our readers a little about you, your work, and the paper that won the award.  Octavio Perez: The paper that was selected as winner of the award was related to my doctorate research that was conducted at Mt. Sinai hospital in New York City in the emergency department simulation center. Now, after finishing my PhD, I'm an adjunct researcher. What we mainly do is look for funding opportunities to set up research in order to provide more evidence, especially in the patient rooms, so that we can improve the patients' length of stay and healing, using light.  LED professional: What exactly did you study?  Octavio Perez: I studied mechanical engineering – a long time ago! I moved around in different businesses, and then in 2011 I was involved in a very interesting lighting project and then I was invited to go back to university part time, by the Queensland University of Technology to begin my Master's in lighting. They asked me to go to Mount Sinai to do my doctorate research because it was a new field and we needed to do the work there. Also, Mount Sinai got the funding from the NIH – The National Institute of Health – and this was great because it meant we were getting the money from the top U.S. agency for health.  LED professional: Is your work in the emergency department a central topic for you or does it cover other topics?  IMG: Questions: Dr. Perez is carefully listening to the questions and makes notes  Octavio Perez: Yes – I work in three main areas. One is the E.D. and how to improve the E.D. clinicians and staff. This is because the burnout rate and suicide for E.D. clinicians is higher than any other profession in the entire world. And this is why I presented the fact that we were able to reduce the perception of sleepiness and the perception of workload. This is extremely important because it is related to stress and this is what you want to reduce. So we proposed to do light treatments – but it is more related to acute effects of light during the day. It's not about circadian lighting. And now, the national academy of medicine in the U.S. has deemed this program a priority. It started a study on clinician burnout in 2017.  Another one, but I can't tell you much about it due to liability issues, is our work on the patients' rooms, where we are focused on improving the sleeping conditions of the patients.  The third one is on surgery rooms. Here we have what I call "competing demands of lighting". The reason for this is because you have different people working in the room: you have the nurses and you have the surgeon and you also have the anesthesiologists. The people from anesthesia are like pilots. They are there at the beginning of the surgery (takeoff), then they are there during the surgery (cruise) and then, at the end of the surgery (landing), they have to be there again. Many times, during the cruise time, they don't pay attention, they are even sleeping, and that's when something can go wrong and sometimes does. So it's important for them to have conditions that support them being awake. Not alert – you don't want people being alert, you want them to be awake! Being alert means stress. What you want, though, is for these people to be awake and focused on their work. And a second point here would be competing demands. You have something like regular surgery, then you have laparoscopy where you need a totally different lighting system, and the third one is remote surgery. These are fields that we are pursuing.  LED professional: So all in all, your research is in the field of medicine.  Octavio Perez: Yes. And the discussion now in healthcare is moving the patient room to homes sometime in the future. This means that we need to think about improving lighting conditions in homes, especially for elderly people. There are two reasons for this: The elderly are the most sensitive population in two areas: One, they fall and they break bones. This is a liability for the hospital. Two, they get hospital acquired infections. So if you don't move the patient to the patient room and you can treat them in their homes, you can avoid both of these problems. If they fall, it's their own fault, and not that of the hospital. And they will not acquire infections at the hospital because they are in their homes.  IMG - Dummy: Light parameters were accurately controlled to guarantee stable test conditions to avoid possible unwanted side-effects that could affect the results  LED professional: If we focus on your work in the emergency department, could you tell our readers what the main setting and outcome was in the paper that won the Scientific Award?  Octavio Perez: The research question is: Can we improve clinician wellness and performance through lighting? The next question is: How are we going to study it? You don't go in trying to prove it. You research it. If you want to prove something – that's not science. So we go into this because I have, through my knowledge, an idea that blue-enriched lighting will have an acute effect on clinician wellness and performance during the execution of clinical procedures compared to the lighting that they currently have. And it's very important to have the control conditions because you can find research from very well known people that are saying something like – red light has an acute effect. And this is true, if you compare it with darkness. It doesn't mean that it is the right condition, because you are comparing against darkness.  So the hypothesis was to conduct research in a room that was set up for training. And we needed a total intervention. So we painted the room – and this was very important because the room is a part of the lighting system in that it reflects the light. Then we installed a system based on indirect lighting. The system has 54 channels so we can change, not only the spectrum, but also the directionality of light. We can have the light going upwards or downwards and you are also able to change wavelengths.  IMG - Colors: The system has 54 channels that allow for the changing of the spectrum and directionality of light. For the study the CCT was set to around 78,000 K and the color-rendering index R9 was perfect at 84 (main image). The small images show other color setting possibilities   LED professional: In your lecture you said that you had extremely high color temperature and you also had a very good color rendering.  Octavio Perez: Yes, the color temperature was around 78,000 K and the color-rendering index R9 was perfect at 84.   LED professional: What was surprising to me was the completely changeable directionality. Did you use this opportunity just to find a setting for all of the research or did the research go on for so long that you could try out different settings?  Octavio Perez: During the research we went for a very special setting because it's exploratory research with limited funding and limited experimental grounds. So the idea was to go to an extreme to see if something was going to happen or not. Other studies will show if this is the right parameter or not, but we did show that clinician performance and wellbeing could be improved with lighting.  LED professional: So that means that these opportunities are already implemented and if you get more funding you'll be able to narrow down the most important influence factors.  Octavio Perez: Yes. As it is related to the clinician – the clinician would prefer a different setting. Here we have to be very careful because many people are working on preferences – they go to the clinician and ask them which one he or she prefers. The clinician says, "Oh, I like this one." But what happens is the opposite. People that refused the system at the beginning, even had a feeling of nausea for the first two minutes, but by the end of the experiment, these were the people hat had the highest improvement when compared to the control conditions. The reason for this was that the lighting was affecting them more even if they didn't like it at the beginning. So you have to be very critical of it when you ask for preferences. Most people choose what is in their comfort zone. But this is the wrong approach. You have to choose the performance zone.  LED professional: I think that is a very critical point because if you are pushing people in the performance zone, how long can they keep it up before they need to come down again and relax?  Octavio Perez: Yes, and that is the main question. It's all about the effects and the dose. The correct term for it is the pharmacal dynamics of lighting. It tells us what is going on with the amount of light you receive, the dose and the effect and how long it affects your body. LED professional: How long did the clinicians stay in the emergency room?  Octavio Perez: Fifteen to twenty minutes. Without question, you need to adapt to the environment. So we had questionnaires and we did them inside the room before and after the treatment. The ones before were about adapting to the environment.  LED professional: Is the short work period typical for clinicians in the E.D.?  Octavio Perez: Yes.  LED professional: So if they have one emergency case, they treat the patient and then they leave and have a rest.  Octavio Perez: Yes, or another clinician comes in and takes over. In the E.D., you have two different areas: One is called resuscitation. It's the one where, for example, there is someone from a car accident and there are ten people working on that person trying to bring him back to life. But we're not talking about those ones – we're talking about the patients that have an injury on one part of their body and they need to be prepared for surgery.  LED professional: So what happens if you have a critical patient and the clinician needs a minute or two to adapt to the lighting?  Octavio Perez: The adaption process is usually only the first time that the clinician goes into the room. If you work there every day, it will only take seconds to adapt – after the initial adaptation. What I observed was that once you have become familiar with this type of lighting you like it.  But going back to your original question: you cannot say that a certain type of lighting is good for this or that and for how long. You have to be very careful with lighting. It works for a while but then you have to switch to another one. What I proposed at the hospital is to have a type of amber showers to relax and blue showers to activate the clinician before he enters the room.  This is also something that should be considered for the ambulances, because the first fifteen or twenty minutes are critical for saving a life or losing it.  Color rendition is also very important. One of the problems, I'm not sure if you are familiar with it: In Australia, when they first began with fluorescent lighting in the 1960's death rate of patients increased. The fluorescent lighting didn't allow the clinicians to see the color of the lips when the patient was going into cyanosis. And this is very important in an ambulance.  LED professional: I'd like to touch on the more general topic of Human Centric Lighting now. These days, everybody talks about human centric lighting and everybody seems to have a different understanding of what it really is. What is your understanding of human centric lighting?  Octavio Perez: There are a couple of definitions. One is from the ZVEI in Germany, that talks about the emotional, biological and visual effects of lighting. This is what you would call a simplified definition of human centric lighting. CIE has gone with the term "integrity of lighting", where they speak about potentially beneficial psychophysiological effects on people considering visual and non-visual effects of light. So I think that if you want the big picture you have to add at least two more circles of interaction. One is about ergonomy and the interaction with space. So the lighting in one space is going to be totally different than lighting in another space and it is going to be related to the activity you are performing. This is very important. And the other one is about energy. We cannot forget about energy. Even if it doesn't have to be the main driver we still have to be very careful because the moment you begin to play with the spectrum you will start introducing wavelengths that are very inefficient from an energy point of view. So you have to consider the energy implications even if they are not a priority.  I think that you have to consider what CIE and ZVEI are discussing, then you have to add the context – ergonomics (including visual ergonomics) – and then you have to consider energy to make the whole thing happen. You cannot speak about human centric lighting without speaking about energy. And you cannot speak about human centric lighting without speaking about the activity that will be performed.  In my doctoral dissertation I introduced an author by the name of Gibson. He talks about something that he called "affordances". The affordance is very interesting because it's about the information that the space is giving to your sub-conscious mind. So, for example, if you see a door, you should know by looking at it and the shape of the objects, if it is a push or pull door. And the same thing is true with lighting. And this is where I introduced the term: Non-visual affordances. When you speak about visual, it's clear, but when you speak about non-visual – you don't see it. It's what the lighting configuration is giving to you.  LED professional: Some people talk about improving performance in the patient room using HCL. So I think that there are also some ethical questions, and I was wondering how you see this. When does it start to be an abuse rather than a use of Human Centric Lighting?  Octavio Perez: First of all you have to differentiate between two approaches in ethics. One is precautionary approach, which is very trendy now. It's a misleading "do no harm" approach. Many people say – we don't know enough about it so we don't use it and that way we will do no harm. Then you have the proactionary approach. This approach is based on the concept that "we have the technology, we have the knowledge, we don't need to know the basic science, but with what we know – we can do good." My opinion is that we do more harm by not doing than by doing with the knowledge that we already have. We know basic elements that will improve our conditions and we should use them.  The second thing is – going into doping the spectrum. If you can reproduce daylight with LEDs the ethical question is not there – because you are using a light source that reproduces the light source from which we have evolved. The problems start when you begin to modify the spectrum to have acute effects. It's like you want me to drink coffee instead of water so I will perform better. Let's say the performance raises up 20%. Are you going to pay 20% more money? More free days? More vacation? This is the ethical question – when the company is making more money because the worker is performing better. So when it comes to the lighting – in the future, I think the worker will probably have to sign a paper allowing for HCL lighting to be used. So that's about offices – but what about schools? In schools the ethical question is different. We have studies that show that academic performance can be increased by 20% by using HCL. And what's about students in non- Human Centric Lighting facilities? Should we compensate this somehow?  In healthcare, when you go to the patient room, the patient might tell you that they don't want HCL. When we had fluorescent lighting, even though it wasn't very pleasant, no one complained about it, but now people have started thinking about the lighting. So you have to be very careful. Even though you know that you can improve healing and the length of stay, the patient might say, that he doesn't want this. This means that the patient will have to stay longer – maybe they will pick up an infection. Who will pay for the extra days and treatments? The patient or the insurance company?  What about the clinician? What if the clinicians say they don't want to use the new light? What if they say they want to use incandescent light and then they make an error? Who is responsible for the error? Is it the clinician or the hospital?  So I think that there will be a lot of ethical issues with human centric lighting. It's not going to be easy, especially when it comes to liabilities and the compensation of workers. This is the debate that we are having.  IMG - ipRGC: Fundamental knowledge of the ipRGC mechanisms, visual mechanisms of the eye and brain and the pharmacal dynamics of light is required to design true Human Centric Light [1]  LED professional: Another very interesting point is blue light. On the one side it seems to activate the circadian rhythm and on the other side people are talking about the "blue light hazard" and the possible connection between blue light and cancer. And you are using a very blue light in your experiment. Can you comment on this?  Octavio Perez: I think we have to go back to the pharmacal dynamics of light. You have to know what you are doing because, for example, you can run for one hundred meters, and this can be fine. But if you want to run for one kilometer at a rate of ten seconds per hundred meters, it would probably kill you.  First, we have to define what blue light is. While we are doing that we'll find that we'll be able to differentiate different areas. We know that, depending of the age of the person; something between 460 nm and 490 nm is what will trigger the circadian effect. This will be beneficial in the morning because you will wake up properly but it won't be as good at night. So you would have to have blue depleted light at night. And now you have all these filters and glasses to filter out this wavelength. But the problem is if you filter out this wavelength, you will fall into a depression during the day. We need it to wake up. And it isn't going to damage you in any way. You have it in the sky and nothing happens. And if I compare my spectra with the spectra of the sun in absolute peaks, the blue peak in the E.D. is only 20% of the maximum of daylight.  Also, the advantage of using this area of the spectrum is that it triggers the pupillary light reflex: You constrict your eye and you reduce the amount of light that goes in. So you regulate the light with your natural mechanisms. If you remove this mechanism from the eye, you get glare and extra light. Many people claim that we need amber light at night. The problem is, if you use amber light, your eye won't constrict the pupil. A Scottish clinician discovered that in the 17th century. He realized that constricting your pupil was a non-visual effect – it doesn't need the brain. So what is going to happen when your body can't constrict your pupil because of all the amber light at night?  We know a few mechanisms, but we don't know exactly what each of them does. My opinion – and this is only my opinion – is that we need to have the spectrum that we had when we evolved because this is what our biology knows. And then the biology will react to it. If you begin to have peaks, you have strange things. So you have to be careful with it. You can use peak performance for a few minutes but then you have to release the systems otherwise you burn it out.  Coming back to the blue light: We have receptors in the blue range. I guess that if our eye has these photoreceptors, or is sensitive to these wavelengths, we need it.  Also, blue light at around 480 nm also controls the axial length growth of the eye and if you don't work with it, you will end up with myopia. And this is what is happening. In regards to physical health, my criterion is that we need a balanced spectrum. So coming back to ethical issues, if you you do peaks, you have to be careful.  LED professional: But you're working with 78,000 K and these are not natural conditions.  Octavio Perez: Absolutely not. Peak performance and the acute effect of light. What did the clinician say about this? At the beginning some of them were very disappointed. At the end, when I talked to them they were really surprised that they had been focused on their work and very relaxed. And this is apparently a contradictory effect of blue light. Again – we don't say it out loud, but we have blue light in our dorm and we put it on before we go to sleep – and it's relaxing. So blue light at a low level is relaxing and at a high level it can affect performance greatly.  LED professional: Prof. Cajochen also mentioned something like that. He said that a low dose of blue at a certain time can trigger dopamine and help you to sleep better.  Octavio Perez: Yes – it's more in the cyan area – 500 to 505.  LED professional: So we have to learn a lot more about blue light.  Octavio Perez: I think all these theses are a big business for people selling filters and glasses. The thing you have to be careful with when it comes to blue light in LEDs is that it has a peak and then it has a valley and then it rises again. This happens around 480 and this means that you are not going to regulate your pupil. This is the real hassle. Because if you fill up the valley – nothing happens with this.  IMG - Myopia: By 2050 half of the world's population is expected to be myopic. However, blue light at 480 nm may reduce the risk of myopia. While there is much talk about the "blue light hazard" it has to be mentioned that this discussion mainly concerns blue light below 470 nm. In addition, part of the problem is due to the fact that in most LED lights the spectrum between 470 nm and 500 nm and the trigger for pupil constriction is missing. It is also important to understand that most of this research is based on in vitro cell cultures that do not provide the body's repair mechanisms [1]  LED professional: Is the eye the only receptor that reacts to light?  Octavio Perez: No, it begins with the skin. And this is one of the questions that was raised in the panel discussion. It came about because I introduced the term: Indoor Daylight. The indoor daylight doesn't contain UV or infrared. Do we need UV and infrared? They are probably more important than the blue light. Do we need this range of the spectrum even if they are non-visual? Yes, we do!  LED professional: I guess we should - unfortunately - slowly start to wrap up the interview, if you don't mind, even though we haven't touched all the topics we wanted to talk about.  Octavio Perez: Yes, no problem. But I would like to touch on why human centric lighting is only happening in research and not happening on the market. The first thing is awareness: Probably not many people in the world know about HCL. And if you don't know about it, you won't buy it or demand it. Even if you have a big budget – you won't buy it.  I have heard people say that they think they can sell human centric lighting fixtures for 20% more than regular ones and I have to say to them: "You don't know what you're talking about." You have to sell solutions, not fixtures. If you sell fixtures – you aren't in the human centric lighting business. You can't go into new markets with old arguments.  We probably have to find new sales channels for HCL solutions. Is it still procurement or do we have to go to Human Resources or the departments that are now created and called "Happiness"? You have these departments in the U.S. and they are beginning to be more popular in Europe.  So who is going to enable this from the infrastructure point of view? IT. Because we talk about dynamic lighting, and who knows how to do these types of things? The answer: IT. When you move like this fixture into power over Ethernet, you are going to control through switches, you're going to be linked to information systems where you can link information from the patient to the lighting – this is IT. Facilities are not going to buy it. Commissioning by IT will make it happen.  So probably the channel is wrong. The argument of sales is that it's only about 20% more. It's another value. It's like when you have a typewriter and you have a computer.  They are different products. Even if you can do word processing with both – it's a totally different thing.  This is something that I think is very critical – the arguments and the channels. Wrong arguments. Wrong channels. No value perception.  But the most important one is: "Who are the stakeholders? Who are the players that are going to move this field farther and the comparison they do between railways and airplanes. When we speak about transportation, no one from the railways was promoting airlines. But when air travel started to happen, the railways started to go broke. And this is probably what is going to happen in the lighting industry. Once human centric lighting, intelligent lighting, IoT and what ever else you can think of, begins to happen, lighting industry is going to die and then the IT industry is going to jump in. So we have these two factors that are critical besides all the technology and what's behind it all and how we define it.  LED professional: This was very interesting discussion – thanks so much.  Octavio Perez: Thank you.  References:  [1] Image credits: LED professional Symposium +Expo 2018, Bregenz, Tunable LED Lighting and the Retinal Dopamine Response: A Remedy for Myopia, Dr Stephen A. Mason B Optom FAAO Dip.OT., Sustainable Eye Health Pty Ltd  Dr. Octavio Perez: Dr. Octavio L. Perez is a passionate professional, researcher and scholar who contributes to exploring, developing and bringing to the real world the benefits of light and lighting for human wellbeing and wellness, and ultimately health. He works internationally as an independent consultant, focused in translational research in human centric lighting (HCL), more precisely "affective lighting". Currently developing the HCL business intelligence for LLEDO Lighting in Madrid, Spain, he is also an adjunct researcher at Mount Sinai Hospital in NYC, NY, USA. Dr. Perez serves in several international technical committees and he is a WELL Building Standard Accredited Professional.

Dr. Perez is carefully listening to the questions and makes notes

Octavio Perez: Yes – I work in three main areas. One is the E.D. and how to improve the E.D. clinicians and staff. This is because the burnout rate and suicide for E.D. clinicians is higher than any other profession in the entire world. And this is why I presented the fact that we were able to reduce the perception of sleepiness and the perception of workload. This is extremely important because it is related to stress and this is what you want to reduce. So we proposed to do light treatments – but it is more related to acute effects of light during the day. It's not about circadian lighting. And now, the national academy of medicine in the U.S. has deemed this program a priority. It started a study on clinician burnout in 2017.

Another one, but I can't tell you much about it due to liability issues, is our work on the patients' rooms, where we are focused on improving the sleeping conditions of the patients.

The third one is on surgery rooms. Here we have what I call "competing demands of lighting". The reason for this is because you have different people working in the room: you have the nurses and you have the surgeon and you also have the anesthesiologists. The people from anesthesia are like pilots. They are there at the beginning of the surgery (takeoff), then they are there during the surgery (cruise) and then, at the end of the surgery (landing), they have to be there again. Many times, during the cruise time, they don't pay attention, they are even sleeping, and that's when something can go wrong and sometimes does. So it's important for them to have conditions that support them being awake. Not alert – you don't want people being alert, you want them to be awake! Being alert means stress. What you want, though, is for these people to be awake and focused on their work. And a second point here would be competing demands. You have something like regular surgery, then you have laparoscopy where you need a totally different lighting system, and the third one is remote surgery. These are fields that we are pursuing.

LED professional: So all in all, your research is in the field of medicine.

Octavio Perez: Yes. And the discussion now in healthcare is moving the patient room to homes sometime in the future. This means that we need to think about improving lighting conditions in homes, especially for elderly people. There are two reasons for this: The elderly are the most sensitive population in two areas: One, they fall and they break bones. This is a liability for the hospital. Two, they get hospital acquired infections. So if you don't move the patient to the patient room and you can treat them in their homes, you can avoid both of these problems. If they fall, it's their own fault, and not that of the hospital. And they will not acquire infections at the hospital because they are in their homes.

Light parameters were accurately controlled to guarantee stable test conditions

Light parameters were accurately controlled to guarantee stable test conditions to avoid possible unwanted side-effects that could affect the results

LED professional: If we focus on your work in the emergency department, could you tell our readers what the main setting and outcome was in the paper that won the Scientific Award?

Octavio Perez: The research question is: Can we improve clinician wellness and performance through lighting? The next question is: How are we going to study it? You don't go in trying to prove it. You research it. If you want to prove something – that's not science. So we go into this because I have, through my knowledge, an idea that blue-enriched lighting will have an acute effect on clinician wellness and performance during the execution of clinical procedures compared to the lighting that they currently have. And it's very important to have the control conditions because you can find research from very well known people that are saying something like – red light has an acute effect. And this is true, if you compare it with darkness. It doesn't mean that it is the right condition, because you are comparing against darkness.

So the hypothesis was to conduct research in a room that was set up for training. And we needed a total intervention. So we painted the room – and this was very important because the room is a part of the lighting system in that it reflects the light. Then we installed a system based on indirect lighting. The system has 54 channels so we can change, not only the spectrum, but also the directionality of light. We can have the light going upwards or downwards and you are also able to change wavelengths.

The system has 54 channels that allow for the changing of the spectrum and directionality of light

The system has 54 channels that allow for the changing of the spectrum and directionality of light. For the study the CCT was set to around 78,000 K and the color-rendering index R9 was perfect at 84 (main image). The small images show other color setting possibilities

LED professional: In your lecture you said that you had extremely high color temperature and you also had a very good color rendering.

Octavio Perez: Yes, the color temperature was around 78,000 K and the color-rendering index R9 was perfect at 84.

LED professional: What was surprising to me was the completely changeable directionality. Did you use this opportunity just to find a setting for all of the research or did the research go on for so long that you could try out different settings?

Octavio Perez: During the research we went for a very special setting because it's exploratory research with limited funding and limited experimental grounds. So the idea was to go to an extreme to see if something was going to happen or not. Other studies will show if this is the right parameter or not, but we did show that clinician performance and well-being could be improved with lighting.

LED professional: So that means that these opportunities are already implemented and if you get more funding you'll be able to narrow down the most important influence factors.

Octavio Perez: Yes. As it is related to the clinician – the clinician would prefer a different setting. Here we have to be very careful because many people are working on preferences – they go to the clinician and ask them which one he or she prefers. The clinician says, "Oh, I like this one." But what happens is the opposite. People that refused the system at the beginning, even had a feeling of nausea for the first two minutes, but by the end of the experiment, these were the people hat had the highest improvement when compared to the control conditions. The reason for this was that the lighting was affecting them more even if they didn't like it at the beginning. So you have to be very critical of it when you ask for preferences. Most people choose what is in their comfort zone. But this is the wrong approach. You have to choose the performance zone.

LED professional: I think that is a very critical point because if you are pushing people in the performance zone, how long can they keep it up before they need to come down again and relax?

Octavio Perez: Yes, and that is the main question. It's all about the effects and the dose. The correct term for it is the pharmacal dynamics of lighting. It tells us what is going on with the amount of light you receive, the dose and the effect and how long it affects your body.

LED professional: How long did the clinicians stay in the emergency room?

Octavio Perez: Fifteen to twenty minutes. Without question, you need to adapt to the environment. So we had questionnaires and we did them inside the room before and after the treatment. The ones before were about adapting to the environment.

LED professional: Is the short work period typical for clinicians in the E.D.?

Octavio Perez: Yes.

LED professional: So if they have one emergency case, they treat the patient and then they leave and have a rest.

Octavio Perez: Yes, or another clinician comes in and takes over. In the E.D., you have two different areas: One is called resuscitation. It's the one where, for example, there is someone from a car accident and there are ten people working on that person trying to bring him back to life. But we're not talking about those ones – we're talking about the patients that have an injury on one part of their body and they need to be prepared for surgery.

LED professional: So what happens if you have a critical patient and the clinician needs a minute or two to adapt to the lighting?

Octavio Perez: The adaption process is usually only the first time that the clinician goes into the room. If you work there every day, it will only take seconds to adapt – after the initial adaptation. What I observed was that once you have become familiar with this type of lighting you like it.

But going back to your original question: you cannot say that a certain type of lighting is good for this or that and for how long. You have to be very careful with lighting. It works for a while but then you have to switch to another one. What I proposed at the hospital is to have a type of amber showers to relax and blue showers to activate the clinician before he enters the room.

This is also something that should be considered for the ambulances, because the first fifteen or twenty minutes are critical for saving a life or losing it.

Color rendition is also very important. One of the problems, I'm not sure if you are familiar with it: In Australia, when they first began with fluorescent lighting in the 1960's death rate of patients increased. The fluorescent lighting didn't allow the clinicians to see the color of the lips when the patient was going into cyanosis. And this is very important in an ambulance.

LED professional: I'd like to touch on the more general topic of Human Centric Lighting now. These days, everybody talks about human centric lighting and everybody seems to have a different understanding of what it really is. What is your understanding of human centric lighting?

Octavio Perez: There are a couple of definitions. One is from the ZVEI in Germany, that talks about the emotional, biological and visual effects of lighting. This is what you would call a simplified definition of human centric lighting. CIE has gone with the term "integrity of lighting", where they speak about potentially beneficial psychophysiological effects on people considering visual and non-visual effects of light. So I think that if you want the big picture you have to add at least two more circles of interaction. One is about ergonomy and the interaction with space. So the lighting in one space is going to be totally different than lighting in another space and it is going to be related to the activity you are performing. This is very important. And the other one is about energy. We cannot forget about energy. Even if it doesn't have to be the main driver we still have to be very careful because the moment you begin to play with the spectrum you will start introducing wavelengths that are very inefficient from an energy point of view. So you have to consider the energy implications even if they are not a priority.

I think that you have to consider what CIE and ZVEI are discussing, then you have to add the context – ergonomics (including visual ergonomics) – and then you have to consider energy to make the whole thing happen. You cannot speak about human centric lighting without speaking about energy. And you cannot speak about human centric lighting without speaking about the activity that will be performed.

In my doctoral dissertation I introduced an author by the name of Gibson. He talks about something that he called "affordances". The affordance is very interesting because it's about the information that the space is giving to your sub-conscious mind. So, for example, if you see a door, you should know by looking at it and the shape of the objects, if it is a push or pull door. And the same thing is true with lighting. And this is where I introduced the term: Non-visual affordances. When you speak about visual, it's clear, but when you speak about non-visual – you don't see it. It's what the lighting configuration is giving to you.

LED professional: Some people talk about improving performance in the patient room using HCL. So I think that there are also some ethical questions, and I was wondering how you see this. When does it start to be an abuse rather than a use of Human Centric Lighting?

Octavio Perez: First of all you have to differentiate between two approaches in ethics. One is precautionary approach, which is very trendy now. It's a misleading "do no harm" approach. Many people say – we don't know enough about it so we don't use it and that way we will do no harm. Then you have the proactionary approach. This approach is based on the concept that "we have the technology, we have the knowledge, we don't need to know the basic science, but with what we know – we can do good." My opinion is that we do more harm by not doing than by doing with the knowledge that we already have. We know basic elements that will improve our conditions and we should use them.

The second thing is – going into doping the spectrum. If you can reproduce daylight with LEDs the ethical question is not there – because you are using a light source that reproduces the light source from which we have evolved. The problems start when you begin to modify the spectrum to have acute effects. It's like you want me to drink coffee instead of water so I will perform better. Let's say the performance raises up 20%. Are you going to pay 20% more money? More free days? More vacation? This is the ethical question – when the company is making more money because the worker is performing better. So when it comes to the lighting – in the future, I think the worker will probably have to sign a paper allowing for HCL lighting to be used. So that's about offices – but what about schools? In schools the ethical question is different. We have studies that show that academic performance can be increased by 20% by using HCL. And what's about students in non- Human Centric Lighting facilities? Should we compensate this somehow?

In healthcare, when you go to the patient room, the patient might tell you that they don't want HCL. When we had fluorescent lighting, even though it wasn't very pleasant, no one complained about it, but now people have started thinking about the lighting. So you have to be very careful. Even though you know that you can improve healing and the length of stay, the patient might say, that he doesn't want this. This means that the patient will have to stay longer – maybe they will pick up an infection. Who will pay for the extra days and treatments? The patient or the insurance company?

What about the clinician? What if the clinicians say they don't want to use the new light? What if they say they want to use incandescent light and then they make an error? Who is responsible for the error? Is it the clinician or the hospital?

So I think that there will be a lot of ethical issues with human centric lighting. It's not going to be easy, especially when it comes to liabilities and the compensation of workers. This is the debate that we are having.

Fundamental knowledge of the ipRGC mechanisms, visual mechanisms of the eye and brain and the pharmacal dynamics of light is required Fundamental knowledge of the ipRGC mechanisms, visual mechanisms of the eye and brain and the pharmacal dynamics of light is required to design true Human Centric Light [1]

LED professional: Another very interesting point is blue light. On the one side it seems to activate the circadian rhythm and on the other side people are talking about the "blue light hazard" and the possible connection between blue light and cancer. And you are using a very blue light in your experiment. Can you comment on this?

Octavio Perez: I think we have to go back to the pharmacal dynamics of light. You have to know what you are doing because, for example, you can run for one hundred meters, and this can be fine. But if you want to run for one kilometer at a rate of ten seconds per hundred meters, it would probably kill you.

First, we have to define what blue light is. While we are doing that we'll find that we'll be able to differentiate different areas. We know that, depending of the age of the person; something between 460 nm and 490 nm is what will trigger the circadian effect. This will be beneficial in the morning because you will wake up properly but it won't be as good at night. So you would have to have blue depleted light at night. And now you have all these filters and glasses to filter out this wavelength. But the problem is if you filter out this wavelength, you will fall into a depression during the day. We need it to wake up. And it isn't going to damage you in any way. You have it in the sky and nothing happens. And if I compare my spectra with the spectra of the sun in absolute peaks, the blue peak in the E.D. is only 20% of the maximum of daylight.

Also, the advantage of using this area of the spectrum is that it triggers the pupillary light reflex: You constrict your eye and you reduce the amount of light that goes in. So you regulate the light with your natural mechanisms. If you remove this mechanism from the eye, you get glare and extra light. Many people claim that we need amber light at night. The problem is, if you use amber light, your eye won't constrict the pupil. A Scottish clinician discovered that in the 17th century. He realized that constricting your pupil was a non-visual effect – it doesn't need the brain. So what is going to happen when your body can't constrict your pupil because of all the amber light at night?

We know a few mechanisms, but we don't know exactly what each of them does. My opinion – and this is only my opinion – is that we need to have the spectrum that we had when we evolved because this is what our biology knows. And then the biology will react to it. If you begin to have peaks, you have strange things. So you have to be careful with it. You can use peak performance for a few minutes but then you have to release the systems otherwise you burn it out.

Coming back to the blue light: We have receptors in the blue range. I guess that if our eye has these photoreceptors, or is sensitive to these wavelengths, we need it.

Also, blue light at around 480 nm also controls the axial length growth of the eye and if you don't work with it, you will end up with myopia. And this is what is happening. In regards to physical health, my criterion is that we need a balanced spectrum. So coming back to ethical issues, if you you do peaks, you have to be careful.

LED professional: But you're working with 78,000 K and these are not natural conditions.

Octavio Perez: Absolutely not. Peak performance and the acute effect of light. What did the clinician say about this? At the beginning some of them were very disappointed. At the end, when I talked to them they were really surprised that they had been focused on their work and very relaxed. And this is apparently a contradictory effect of blue light. Again – we don't say it out loud, but we have blue light in our dorm and we put it on before we go to sleep – and it's relaxing. So blue light at a low level is relaxing and at a high level it can affect performance greatly.

LED professional: Prof. Cajochen also mentioned something like that. He said that a low dose of blue at a certain time can trigger dopamine and help you to sleep better.

Octavio Perez: Yes – it's more in the cyan area – 500 to 505.

LED professional: So we have to learn a lot more about blue light.

Octavio Perez: I think all these theses are a big business for people selling filters and glasses. The thing you have to be careful with when it comes to blue light in LEDs is that it has a peak and then it has a valley and then it rises again. This happens around 480 and this means that you are not going to regulate your pupil. This is the real hassle. Because if you fill up the valley – nothing happens with this.

Blue light at 480 nm may reduce the risk of myopia

By 2050 half of the world's population is expected to be myopic. However, blue light at 480 nm may reduce the risk of myopia. While there is much talk about the "blue light hazard" it has to be mentioned that this discussion mainly concerns blue light below 470 nm. In addition, part of the problem is due to the fact that in most LED lights the spectrum between 470 nm and 500 nm and the trigger for pupil constriction is missing. It is also important to understand that most of this research is based on in vitro cell cultures that do not provide the body's repair mechanisms [1]

LED professional: Is the eye the only receptor that reacts to light?

Octavio Perez: No, it begins with the skin. And this is one of the questions that was raised in the panel discussion. It came about because I introduced the term: Indoor Daylight. The indoor daylight doesn't contain UV or infrared. Do we need UV and infrared? They are probably more important than the blue light. Do we need this range of the spectrum even if they are non-visual? Yes, we do!

LED professional: I guess we should - unfortunately - slowly start to wrap up the interview, if you don't mind, even though we haven't touched all the topics we wanted to talk about.

Octavio Perez: Yes, no problem. But I would like to touch on why human centric lighting is only happening in research and not happening on the market. The first thing is awareness: Probably not many people in the world know about HCL. And if you don't know about it, you won't buy it or demand it. Even if you have a big budget – you won't buy it.

I have heard people say that they think they can sell human centric lighting fixtures for 20% more than regular ones and I have to say to them: "You don't know what you're talking about." You have to sell solutions, not fixtures. If you sell fixtures – you aren't in the human centric lighting business. You can't go into new markets with old arguments.

We probably have to find new sales channels for HCL solutions. Is it still procurement or do we have to go to Human Resources or the departments that are now created and called "Happiness"? You have these departments in the U.S. and they are beginning to be more popular in Europe.

So who is going to enable this from the infrastructure point of view? IT. Because we talk about dynamic lighting, and who knows how to do these types of things? The answer: IT. When you move like this fixture into power over Ethernet, you are going to control through switches, you're going to be linked to information systems where you can link information from the patient to the lighting – this is IT. Facilities are not going to buy it. Commissioning by IT will make it happen.

So probably the channel is wrong. The argument of sales is that it's only about 20% more. It's another value. It's like when you have a typewriter and you have a computer.

They are different products. Even if you can do word processing with both – it's a totally different thing.

This is something that I think is very critical – the arguments and the channels. Wrong arguments. Wrong channels. No value perception.

But the most important one is: "Who are the stakeholders? Who are the players that are going to move this field farther and the comparison they do between railways and airplanes. When we speak about transportation, no one from the railways was promoting airlines. But when air travel started to happen, the railways started to go broke. And this is probably what is going to happen in the lighting industry. Once human centric lighting, intelligent lighting, IoT and what ever else you can think of, begins to happen, lighting industry is going to die and then the IT industry is going to jump in. So we have these two factors that are critical besides all the technology and what's behind it all and how we define it.

LED professional: This was very interesting discussion – thanks so much.

Octavio Perez: Thank you.

References:
[1] Image credits: LED professional Symposium +Expo 2018, Bregenz,
     Tunable LED Lighting and the Retinal Dopamine Response: A Remedy for Myopia, Dr Stephen A. Mason B Optom FAAO Dip.OT., Sustainable Eye Health Pty Ltd

Dr. Octavio Perez:

Dr. Octavio L. Perez is a passionate professional, researcher and scholar who contributes to exploring, developing and bringing to the real world the benefits of light and lighting for human wellbeing and wellness, and ultimately health.
He works internationally as an independent consultant, focused in translational research in human centric lighting (HCL), more precisely "affective lighting". Currently developing the HCL business intelligence for LLEDO Lighting in Madrid, Spain, he is also an adjunct researcher at Mount Sinai Hospital in NYC, NY, USA. Dr. Perez serves in several international technical committees and he is a WELL Building Standard Accredited Professional.

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