Sleep & Health
How Does Blue Light Affect Your Sleep
Digital displays in the last two decades have transformed our daily lives and are now almost the main means of seeing the vast ocean of digital information that is available all around us. From television, computers, smartphones, and LED screens, the content displayed not only keeps us informed but can also educate and alerts us. What most people don't realize is that long-term exposure to these electronic displays actually poses health risks, which can disrupt your sleep.
- Blue Light & Brain
- How to Minimize the Eye Damage from Blue Light
- Will it Help to Switch to the Phone Night Shift Mode?
Blue Light & Brain
Electronic displays emit a large number of short wavelengths of light, which is also known as high-frequency light. Since our visual nervous system will perceive short wavelengths of light as subjective “blue”, we generally call these short wavelengths of high-frequency light “blue light”. It is this blue frequency of light that could cause sleep latency, which means the light from your digital device will most likely make it more difficult for you to doze off in the evening.
Blue light is the shortest wavelength and most energetic light that the eye can see. Unlike ultraviolet light, this unique wavelength of light is not absorbed by the cornea and crystalloids and cannot be transmitted to the retina at the base of the eye. The glare tends to produce a scattered image, and the eye tends to feel fatigued because the eyes will always try to naturally stay focused.
In addition to damaging the eyes through stress, blue light has the potential to affect the sleep-wake cycle, which is often referred to as the 'biological clock.' The human physiological clock is regulated by a part of the brain called the suprachiasmatic nucleus (SCN), which coordinates the pineal gland of the brain to properly release the sleeping substance - melatonin. The brain registers the light information (such as light intensity) received by the retina (retina). to regulate the time to fall asleep.
During the evening, the light tends to be dim because of the night. With the help of our physiological clock, the SCN signals the brain to start getting ready for sleep. When this set of instructions is given the pineal glands work with SCN to release melatonin, which causes you to get tired and hopefully doze off.
The world in which we live has changed significantly, even after the industrial revolution. Due to the light pollution in cities, the night is not as dark as before. Before the invention of digital displays, artificial sources of blue light were not easily available. The only major source of blue light naturally was the sun. Yes, sunlight! The light that separates day and night. Our natural bodily function from an evolutionary standpoint used sunlight in the management of being active during the day and resting during the night. Nowadays, digital displays are everywhere, the blue light that is emitted from the screen negatively impacts the very controls that are involved in our sleep cycle making it harder to fall asleep.
The “retinohypothalamic path” is the name given to the pathway that connects the SCN to the retina of our eye, as was previously demonstrated. The unique aspect of this pathway is that it originates from a very unique retinal ganglion cell, as opposed to the more generally recognized cone or rod cell, which is highly sensitive to short-wavelength blue light. As a result, when we are exposed to blue light at night when the lights are dim, the brain's SCN will wrongly interpret it as a signal for daytime and will modify the pineal gland to release less melatonin, which will diminish our tiredness. Over time, the SCN will begin to confuse when it is daytime and when it is nighttime, which will have an impact on our biological clock and sleep rhythm. It is a lack of restorative sleep that has long-term risks that can affect our health and day-to-day activities.
How to Minimize the Eye Damage from Blue Light
- Avoid electronic devices before bed. Remember not to use electronic devices close to bedtime as the blue light disrupts your natural sleep rhythm and causes sleep latency. Try to be in a comfortable state without any forms of interference or disturbance.
- Do not use displays in a dimly lit room. The iris of the eyes opens up in a dimly lit room in order to enhance vision. If you are looking at an artificially bright device in a dark room, it causes eye strain. and damage over time.
- Anti-Blue Light Glasses. Wearing anti-blue light glasses when using electronic devices, can help you filter blue light so that your eyes can view the screen and minimize strain damage.
- Using sleep-friendly gadgets. If you feel eye stress or having difficulties falling asleep, an eye mask can help a lot. Compare to disposable steam eye masks, a portable eye massager mask, with a built-in heating and cooling element, works gently to relieve eye stress.
Will it Help to Switch to the Phone Night Shift Mode?
The hazard of blue light from electronic screens has begun to attract attention in the past few years. There are a lot of anti-blue light solutions on the market, and Apple also included a “Night Shift” option to IOS 9.3 in 2016 to cut down on blue light, but British researchers recently discovered that a warm light view may not aid in sleep and may even worsen insomnia.
First of all, there is indeed a scientific basis for the night vision model. There is a ganglion cell protein in our retina called "melanopsin" (also called retinoid), which response to the intensity of light, especially the shorter wavelength of blue light, which in turn resists the secretion of melatonin and ultimately affects sleep.
Each pixel of the phone screen consists of red, blue, and green sub-pixels, the blue sub-pixel has the shortest wavelength, the principle of the night view mode is to significantly reduce the brightness of the blue sub-pixel or even turn it off completely, so the screen will appear yellowish phenomenon.
Since there is nothing wrong, why does night vision still prevent sleep? The problem lies in the longer average wavelength of light in Night Shift mode.
The benefits of reducing blue light were completely offset by yellow light, or even counterproductive, as evidenced by experiments on rats conducted by researchers at Manchester University, who discovered that when the phone was in night-viewing mode, the cone cells in the eye responded much more strongly to the yellow color than the dark-vision protein did to blue light. This is because when it comes to sending biological clock signals to the brain to determine whether it is day or night, the co-opting yellow light is actually counterproductive. Cone cells may have a greater "say" in the process of sending signals from the biological clock to the brain whether it is day or night. As a result of the heated screen’s stimulation, the visual cone cells become especially active, disrupting the workday.
Although this conclusion is based only on the researchers' observation of the rats under various lighting conditions, it is not particularly rigorous. The study's findings revealed that high-intensity yellow and white light—which our bodies are exposed to the most during the day—have the biggest effects on the sleep cycle.
In short, whether it is the results of research or common sense tell us that what affects our sleep is actually the phone itself, the lighted phone screen is undoubtedly telling the brain that we do not want to sleep, so the best and easiest way to avoid the phone to prevent sleep is not to use it.