Don't Look Into The Blue Light
Hello and thank you for joining me today for “Don’t Look into the Blue Light”. My name is Dani Hill and I am one of the health educators with health and preventive services. I wanted to thank you for your time today.
We are going to go over the topic of blue light and a lot of this is stemming from an interest that I have gained over the course of the last year with working from home and having my children doing school virtually. It has piqued a lot of interest; I'm sure, for many of you as well.
Today what we're going to do is discuss in detail about blue light and how it interacts with our eye, then we'll go into some of the health claims around blue light and finish up with some of these light/blue light reduction products, and if they are beneficial.
So to begin, we have to understand what exactly blue light is and for that, we're going to need to go back to science. I'm curious if many of you remember learning about the electromagnetic spectrum. Essentially, what’s happening is the sun is continuously expelling energy down to earth. Earth receives that energy in different degrees of intensity; some of which our atmosphere protects us from. But most of the energy that's coming down (in the form of these wavelengths that you're seeing on your screen) isn't visible to us.
However, we do have a small slice of it that we can see and that's visible light. We know about visible light because that's how we're able to see our world in color. And as you're looking on your screen, what you'll notice is that over on the left hand side, we have these wavelengths that have pretty considerable space between the peaks. As we move to the right the space between this gets smaller and smaller. And what that, what that is illustrating to us, is that as we move farther down the spectrum, farther to the right, the intensity of that light becomes greater and greater so it can pose some more health risk to us.
We're familiar with visible light because that's how we, again, see the world in color. We learn about the rainbow at a very early age. We know about ROY G BIV - the acronym for the colors of the rainbow. Well, when we combine all of these colors together, we get white light, or what we see when we look at the sun. However, if you think about a day that you've been outside where it was rainy and then the sun came out, we might see a rainbow in the sky. That's when the rain in the sky, the water in the sky, is acting as a prism for us and breaking that light apart into the different colors of the rainbow. The same can be said for when we're outside and it's a bright, sunny day, we might notice that the sun is shining and the sky is bright blue and you may have had a child or grandchild in the past ask you why the sky is blue or you may have wondered that yourself. And that's because blue light scatters more broadly than all the other colors of the rainbow. It has a more intense, higher frequency wavelength that we just talked about, than some of our other colors and it's just able to interact with the particles in the atmosphere better.
So, blue light certainly is very powerful. Blue light from the sun can be beneficial to us. During daylight hours, sunlight can help to boost our mood and our alertness. Sunshine during the day can also help us to sleep better at night. I know for me personally, I'm usually much more productive on days. That are bright and sunny versus those that are rainy and overcast. However, the vast majority of our smart gadgets nowadays contain blue light as well. And if you follow wellness trends at all, you've probably seen or heard something about the claimed health concerns around the amount of blue light that comes from our devices. So, we're going to take a second to understand how blue light impacts our eyes to lay a foundation for these claims.
So, you're looking at a depiction or illustration of the eye here and this would be someone looking to their right. So the outer layer of the eye is the cornea and light passes through that section first. That's the clear front layer of our eye. The cornea is shaped like a dome. It helps to bend the light to help the eye focus so similar to what we talked about with a rainbow in the sky. When there's water droplets in the sky, they act as little prisms. They help to bend the light so that we can see the different colors of the rainbow. The cornea is doing something similar for us. Some of that light passes through the cornea. It enters the eye through an opening called the pupil. And then the iris, on the outside of the pupil (that colored part of our eye) helps to control how much light the pupil lets in. So if you've ever had your eyes dilated and stepped outside, you realize that it's just so incredibly bright. Because your pupil is much larger versus if you're in the dark and your pupil’s big, that helps you to see a lot better. After we passed through the iris and pupil, we then go through the lens. That's the clear inner part of the eye and the lens works together with the cornea to help focus the light correctly onto the retina. And when the light hits the retina, that's our light sensitive layer of tissue at the back of the eye, there are specialized cells in the retina that are called photo receptors. And this is going to be something that you'll hear me refer to throughout the course of the presentation, these photoreceptors, these specialized cells in the retina, help to turn light into electrical signals. Those signals then travel from the retina through the optic nerve, at the back of the eye, and then go up to the brain and the brain turns those signals into images that we see.
There is something important about this process and that is the production of tears. Tears help to keep our eyes wet and smooth. They help us to focus light so that we can see clearly. Every time we blink there's a thin layer of tears called a tear film that spreads across the surface of our cornea. When we're not making tears correctly, or if we're not making them enough, then we tend to have dry eye. And dry eye makes it difficult for us to perceive light the correct way. So, why is there concern around blue light in the eye, as opposed to some of the other colors on the light spectrum? Well, basically, our eyes aren't good at blocking blue light as well as they are at blocking other colors on that light spectrum, which is what I want to try to simulate for you here in the second. What you're going to see is that this light is going to pass through the different colors of light, not blue light, but the others pass through, um, different sections of the retina. So the retina is getting partial amounts of those other colors. However, almost all blue light can pass through the back of the retina. It has more of a straight shot; a little bit better at taking that light in. Almost all blue light, like I mentioned, passes through the retina.
So, now that we have an understanding of how blue light may be more easily transmitted through the eye and that it’s a more impactful, a higher frequency light on the light spectrum, now we can lay the foundation as to whether or not there's good, bad, or no difference in terms of our overall health. You Google that question - “How does blue light impact health”? You're more likely than not to find answers that fall into 1 of these 3 categories: eye disease, sleep health and eye discomfort. So what I thought we would do is talk through each of these categories and examine the research versus the claims. So we're going to get started first with eye disease.
And here's a question for you to think about for a second: can blue light can cause some forms of eye disease? As we just talked about, blue light is a higher frequency and it moves through the back of the retina much more effectively than the other colors of the rainbow. So, what would your answer be here? Well, the answer is actually: No. We're going to go through this a little bit to explore why.
So, if we go back to our eye anatomy, you'll remember that light passes through the eye and makes its way to the retina where a little physiology happens to take that light and convert it into a signal that the brain understands as an image. You'll also remember, from our previous slides, that blue light is lighter, excuse me, is a higher energy light. It has a smaller wavelength. In essence, the claim here is that blue light enters the retina and, because of its high energy, it causes these retinal cells, the specialized cells that we talked about, to die which, in turn, results in different forms of disease developing in the retina. That's the claim. Here's what's fascinating about that theory: it comes, in large part, from the results of one study. This one study was kind of the catalyst of this claim; made for big headlines - specifically that blue light could cause everything from blindness to macular degeneration to cancer because of this cell death that we just went over. But, the author of the study himself is quoted as saying that the results should not conclude that. Let's talk about why.
Here's the gist the study, those specialized cells in the retina (those photoreceptors) utilize a molecule called retinal to sense light and trigger that cascade of signaling to the brain. So, researchers wanted to look at what happens when retinal (this molecule) is exposed to blue light. So, what they did was they, they took retinal, they beamed it with blue light and it triggered a reaction that basically generated a poisonous chemical in the molecule. So, retinal basically deteriorated into a toxic molecule and when that toxic molecule interacted with the cells, the cells died. But, the study's findings could not be turned into recommendations for the real world and here is why. First off, the experiment didn't mimic what happens in live eyes. The cells that were used for the the study were not derived from retinal cells; were not derived from those specialized photoreceptors. The cells in the study were also not exposed blue light in the way that cells in a live eye would naturally be exposed to blue light. And third, the cells, part of those cells, um, that were affected by retinal in the experiments do not touch retinal in the eyes of living people. So there's 3 components to that first consideration. These live cells: (1) were not cells that are typically found in the retina, (2) were not exposed to blue light and the way that they would be naturally and (3) were not interacting with retinal in the way that retinal would interact with cells within the retina. So that's the 1st consideration. The next one is that retinal is toxic to some cells whether or not it's exposed to blue light.
Live cells in the retinal, in the retina, excuse me, have proteins that protect them from those possible toxic effects. So, the specialized cells in the retina have a way to protect themselves against those toxins naturally. And the thirrd consideration is that other cells that were exposed to this retinal, the toxic retinal and blue light, by these investigators were not exposed to blue light as they would be in the body. Blue light only reaches the skin and the eyes. It can't have a deeper effect in the body. So, um, it's hard to take a cell that's not from the retina, expose it to blue light and consider that is how it, the retinal cells, would interact with it as well because they're not the same. In other words, the researchers took cells that were not from the eye, put them together with a retinal in a way that doesn't happen in the body and exposed the cells to light in a way that doesn't happen in the real world. So far, evidence from research, like this one, have not found any meaningful link between blue light and damage to a human retina. So that's why the claim doesn't fall true. So far there just hasn't been a study that's been able to prove that blue light interacting with retina cells, as it would in the in real life, would have this type of impact.
Next let's move on to sleep health. The common thought around sleep health and blue light is that excess blue light can disrupt sleep. So, my question for you is, can blue light make it more difficult to sleep? The answer to this one is yes, so let's explore it.
First off, we need to think about two internal biological mechanisms that happen in the body that help us to sleep. One is circadian rhythm and this directs a wide variety of functions in our body. Obviously we are most familiar with circadian rhythm and our ability to sleep. However, there are other circcadian rhythms in the body that control things like our body temperature, our metabolism, um, release of different hormones in the body. These rhythms, um, are running on a biological clock, a 24 hour clock that, um, our body sets and utilizes a lot of environmental cues, things like a light and temperature. But probably the most potent those is, um, is light. However, our biological clock, and our circadian rhythms, can continue to function even in the absence of those cues. So, let's think of an example of when we travel to a different time zone. So let's say, are you based on the East Coast and it's 5 o'clock in the morning and you want to fly out to California. When you get to California it’s, you know, 6 o'clock in the morning there, your body feels like it might be 9 o'clock in the morning. Right? So our body continues to function on the biological clock that we set even in the absence of the cues that help us to understand what time of day it is. The other process or mechanism that helps us to maintain our sleep patterns is something called sleep wake homeostasis and this tracks our need for sleep. This is a sleep drive.
It helps to remind our body that we need to go to sleep after a certain time and it helps to regulate how deep we're sleeping when we are sleep. Um, the sleep drive gets stronger every hour that we're awake. It causes us to sleep longer and more deeply after a period of sleep deprivation and the example, I like to use to illustrate this is a pressure cooker. If you've ever cooked anything in a pressure cooker (instant pot) you know when you put your food in and you close the lid and turn the timer on, your food doesn't instantly start to cook. It has to build pressure up within that internal component before the food begins to cook. And similar is what's going on with our sleep drive in our body. The pressure for us to sleep has to build and it does that throughout the day. There are some factors that can influence when we feel sleepy and when we feel awake. Those are things like medical conditions, medications, stress or sleep environment, even what we eat and drink.
But perhaps the greatest influence on our need for sleep and our need to be awake is exposure to light. And again, we have those specialized cells (those photoreceptors) in the retina of our eye that processes light and tells our brain whether or not it's day or night and can advance or delay our sleep wake cycle. So, exposure to light can make it difficult to fall asleep and can make it difficult to return to sleep if we are woken up in the middle of night. What's interesting is that exposure to all colors of light kind of help control our natural circadian rhythm. So, some, some light, um, helps us to understand that it's getting darker, uh, think about, you know, if it's been a bright day outside the sky's nice and blue, but as the sunsets, the sky might turn into like a orange yellow. Our body understands those colors as that it’s getting closer to bedtime. Blue light, however, has more of an ability to mess with that sleep wake cycle more than any other color and that's because it can impact our body’s ability to produce and release a hormone melatonin. Melatonin helps us to feel sleepy. It helps to allow us to go to bed at night and keep us asleep. Blue light has the ability to interfere with a natural release of that hormone. Our last claim involves blue light’s responsibility for eye discomfort. So, the question here is: is blue light responsible for eye discomfort from smart gadgets? So, things like our TVs, computers, tablets, cell phones and the blue light coming off of those - is that impacting our eye comfort?
And the answer here again is no, so let's dive into it. So, eye discomfort is usually referred to as either digital eye strain or computer vision syndrome and it's accompanied by one or more of the symptoms that you see listed on your screen. It happens because your eyes follow the same path over and over again when you're looking at a monitor or a screen of any sort, and it can get worse the longer you continue that movement. Think about muscle movement, muscle memory in your body. Your eyes are doing the same thing. When we're working on a computer or a device, like a tablet or cell phone, our eyes have to focus and refocus all the time. So they move back and forth as we read. They might need to look up. It looks down at papers and then backup on our screen to type something. So our eyes are constantly reacting to a change in images. We talked about, how the light comes in and we perceive those light, those different colors of light as images. Well, our eyes are constantly darting back and forth when we're looking at screens, having the shift focus. And so we're sending rapidly varying images to the brain. All of these jobs require a lot of effort on our eye muscles and to make things worse, unlike looking at a book, or a piece of paper, our screens have considerable contrast in them. A lot of, uh, you know, white and black next to each other for example, we have flicker on our screens, um, that causes a lot of movement and also glare from our screens. What's more? It's proven that we blink far less frequently when we're looking at a smart gadget and that causes an increase in our eyes, drying out;l causes our vision to blur, periodically, while we're working at the computer, or are looking at a device for a long period of time.
As we talked about in the beginning of our presentation, the production of tears and that tear film that we get from blinking are important for how our eyes are perceiving light, so we are losing out on our typical blinking patterns when we're looking at computers or any other digital device for a long time.
So, now that we understand more about how blue right interacts with our eyes, let's talk about ways to reduce the impact of digital devices on our eyes, and on our health. We're going to do that by going to the same three categories again. So, first, eye disease. As we talked about, the claim is that blue light from smart devices is entering the retina and damaging the cells which can lead to a range of eye diseases or eye disorders. We've already discussed how that claim has not been backed up by science and that research, um, that's investigated this really hasn't drawn the same conclusion as what you might see in the headlines. So, blue light blocking glasses or screen protectors, or any of those other products that are marketed to prevent eye disease from blue light, aren't really preventing anything based on current science.
However, we also talked about blue light coming from sunlight and, in addition to the blue light coming from the sun, we are also getting exposed to a great deal of UV light from the sun. As a reminder UV light isn't visible to us, but it sits just to the right of visible light on the electromagnetic spectrum. It's a shorter wavelength so it's a stronger, um, higher frequency energy that we have to consider. UV radiation can damage the anatomy within the eye. So, um, some of the conditions that you might see or eye diseases that you might see from high exposure to UV radiation from the sun can be things like cataracts and eye cancers. These can take years to develop but each time you spend time in the sun without protection, you're certainly increasing your risk. Another one that you might notice is growths on the eye that can appear as early as our teens and 20’s. And then, lastly, um, snow, sand, ice or water blindness can quickly develop when UV light is reflecting off of those surfaces. So we definitely can have some impact from the sun and eye disease.
So, what can we do? Well, to protect our eyes, regardless of the season, here some things that you might want to consider. First is to pick out the right kinds of sunglasses to wear. Many sunglasses that we shop for we don't look at the UV rating before we purchase a pair. You want to make sure that you're looking at that. You want to have sunglasses that are providing you with 100% UV protection or it might be referred to as UV400 protection, or look for something that, you know, advertises that it blocks both UV-A and UV-B rays. The next is that we want to wear a hat along with our sunglasses. Broad brimmed are certainly going to be the best. Even if it's cloudy outside, don't think that that means the UV light is not coming through. Clouds do not block UV light. Uh, the sun's rays can pass right through those haze and clouds. So make sure you're considering that when you're outdoors on cloudy days. Next sunlight is the strongest from midday to early afternoon, um, at higher altitudes and when light is being reflected off of the surfaces that I mentioned before: s, water, ice or snow. Be mindful of that. Next, never looked directly into the sun. Doing so at any time, even during an eclipse, can damage your eyes’ retina. It can cause some serious injury to your retina so, um, you know, things like the eclipse - we have special glasses that you use to look at an Eclipse. There was one what maybe 3 or 4 years ago that, um, that was we all heard about - don't look directly into the sun at that time. So, take that into consideration. And then last thing, avoid tanning beds. Tanning beds pose the same risks to your eyes and body as outdoor sunlight. One thing that's important to consider, is that some damage, whether it's to our eyes, or to our skin applies to everyone regardless of age. So everyone from infants to seniors can have an impact from, um, sunlight so consider these rules for everyone. One thing also to remember is that healthy exposure to sunlight can have really positive effects as long as you're protecting your eyes from the damage. For one, you need a little natural light every day to help you sleep, like, we talked about and also spending time outdoors during daylight is a great way to help kids prevent nearsightedness. So make sure you're spending time outside, getting some fresh air, but just make sure that you're protecting yourself with hat, sunglasses and sunscreen.
Alright now that we've talked about eye disease, let's move on to sleep health. So what do we do to get a better night’s sleep? If you're having a difficult time getting to sleep or staying asleep at night and you're guilty of having your phone, your computer, TV, et cetera on at that time, are there products out there that can help? Well, the answer is yes but you don't necessarily need them. The simplest way that you can, um, lower your exposure to artificial blue light at night is just to turn your gadgets off well, before bedtime. There's some other things that you can do. You certainly can purchase blue light blocking glasses. They’re everywhere nowadays. Ones that have an amber or brown tint to the lens may help the best. But also consider just cutting back your screen time, maybe a few hours before bed. Certainly dimming the brightness on your devices will help. This is often called night mode or dark load. It helps to change the background from your screens from a white to a black. And that helps with the amount of blue light coming through. You can also look at installing some of the blue light filtering apps onto your smart devices as well. They filter out a lot of the light from reaching your eyes without making it harder to see your display. Another thing that you might want to consider is swapping out your light bulbs. LED lights give off more blue light than fluorescent lights. They both admit more blue light than incandescent bulb, which you know to be the energy hungry bolts. Um, those are starting to be phased out. But you can also think about using a dim red light bulb as a nightlight. Red light is a color that tends to affect our circadian rhythm the least. So that's something else to consider. Another is to set an alarm about an hour before bed. That'll help you to remember to put your devices away. If you are someone that likes to lay in bed and watch TV, for example, try switching to an audio book or a podcast, allow yourself to wind down. It's going to be more beneficial to your overall sleep if you're being impacted by, um, exposure to your smart devices in the evening.
Last, but not least, let's talk about, again, digital eye strain. Again, we learned that eye strain is not being caused specifically by the blue light being emitted from our screens but by the amount of work our eyes have to do to look at these things as well as the amount of time that we spend looking at them. So, what are some tools or best practices that we can use to give our eyes a break? The first is to take breaks and we can do that by using the 20-20-20 rule. This rule basically says every 20 minutes that you're looking at a screen, take a second, turn away from your screen and look at an object that's 20 feet away for at least 20 seconds. All right, so let me repeat that again. The 20-20-20 rule every 20 minutes look away from your screen at an object that's 20 feet away for at least 20 seconds. This gives your eyes a chance to reset and replenish themselves. The next is to use artificial tears to lubricate your eyes. Um, when they feel dry again, you'll have the beneficial impact of that tear film that we talked about before. Next keep your distance, you should be about 25 inches, or roughly the length of your arm, away from your screen and adjust your height of your screen. So that you're looking slightly downward that will help with the amount of light coming in to the back of the retina. Another thing we can do is reduce the glare and the brightness from our devices. Devices with glass screens usually cause more glare, so to reduce that you can look at buying one of the matte screen filters for your device. Um, also just adjusting the brightness and contrast on your screen, dimming the light, uh, near your screen can also help to reduce the ice drainage you're getting. And then, finally, if you're a contact lens wearer consider switching to eyeglasses, uh, when you're working at a computer for long periods of time. That can help to reduce the dryness and irritation that you may be feeling from looking at the screen.
So, the final question here is do you need to buy blue light glasses? The overwhelming response I saw from resource after resource after resource while I was building this presentation was - if you want to wear them, wear them. But they're not the end all to be all. If anything you may notice a difference in that digital ice stream that we talked about or your ability to sleep better at night, but they're not necessarily helping to reduce your risk of eye disease as we've discussed throughout the presentation. I didn't find any resources that suggested that they were harmful, but you might be just experiencing a placebo effect. If you practice some of the other habits that we discussed, you're likely to experience some of the same benefits.
But if you are interested in learning more about blue eye, blue light, and, or eye health in general, I highly recommend checking out the American Academy of Ophthalmology. Their website is awesome. There's a section that's specifically to the public and patients. It's robust. It provides really great information about blue light as well as many other topics.
Wanted to say thank you to you for joining me for this presentation. Every month we have another live presentation that we welcome you to come visit us and and join us for. If not, you're welcome to come back to the website here on optimahealth.com and look for some of our other archived presentations at your convenience. Thanks so much and have a great day.
Last Updated: 1/26/2021