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All About Blue Light

In this digital era, it is difficult to avoid television, smartphones, laptops, or any electronic devices. Other than the content you see, do you know something emitting from the devices is potentially harmful to your eyes? Should you be concerned about the blue light? It can cause blurred vision, dry eyes, cataracts, and also sleep problems. Here we are going to break down blue light and learn how to reduce the exposure.


What Is blue light?


Electromagnetic radiation is composed of various waves such as ultraviolet (UV) rays, gamma waves, microwaves, most of which are invisible. However, the electromagnetic spectrum also includes visible light, which is the area in which blue light falls. According to Healthline, blue light has short, high-energy waves, which are only slightly less potent than UV light. We have always been told to stay away from UV light rays from the sun, but blue light can be as damaging as those rays.


Image is courtesy of ResearchGate.


Where can we find blue light?


Blue light can be found everywhere. Sun is the main and natural source, but other sources include fluorescent light, light-emitting diode (LED) light, computer tablets, and flat-screen televisions that can emit up to 490 nanometers. However, most concerns regarding blue light have been referring to technology. We are exposed to it for much longer periods and closer distances than the sun, as the Canadian Association of Optometrists (CAO) explains.

Image is courtesy of Designecologist via Pexels.


What Are the Benefits of Blue Light?


Although we typically hear the detrimental effects of blue light, our body also needs blue light to function properly.


Helps With Memory


Research from PLoS One shows that 30-minute exposure of blue light performs better on memory consolidation compared to amber light exposure.


Regulates Circadian Rhythms


The Sleep Foundation explains that light is the most crucial factor regarding circadian rhythms as they align with sunrise and sunset. This is because exposure to blue light helps suppress melatonin production, which in turn stimulates our brain, boosts alertness, and raises body temperature and heart rate. Some treatments like bright light therapy have been shown to treat sleeping disorders such as delayed sleep phase syndrome (DSPS), advanced sleep phase syndrome (ASPS), and insomnia, according to Stanford Healthcare. It uses a technique called phototherapy to shift sleeping patterns back to normal gradually.


Boosts Alertness and Performance


As mentioned above, blue light alters our circadian rhythms, which improves alertness. A Frontiers in Psychology study shows that blue light enriched white light enhances vigilance and cognitive performance of the day, as shown in the results of morning and evening drivers. The Journal of Biophotonics states that this is likely because blue light stimulates alpha wavelengths associated with alertness, stimulating your brain even if you are not at peak performance of the day.


Improves Seasonal Affective Depression (SAD)


SAD describes people who have depression symptoms during the fall and winter. Symptoms include lack of energy, depressed mood, changes in appetites, etc. It is thought to be caused by hormonal imbalances in the brain due to the shorter daylight. Since blue light suppresses melatonin, phototherapy can help to boost energy levels, improve mood, and positively contribute to one's well-being and happiness, according to MedicineNet.


How Does Blue Light Affect Your Eyes?


Digital Eye Strain


Prevent Blindness writes that blue light from digital devices decreases the contrast of light, which can cause eye strain. Research from the National Library of Medicine has shown that smartphones and tablets are associated with visual and ocular discomfort. Since we often blink less when staring at a screen, it causes eye strain such as dry eyes, sore eyes, irritated eyes, difficulty focusing, and headaches.


Lens Damage


The lens in each of our eyes contains structural proteins, enzymes, and protein metabolites that can filter short light waves to reduce retinal light damage, as stated by the International Journal of Opthalmology. However, long-term exposure to blue light can reduce the protection and reduce the lens’ transparency which causes cataract formation.


Retina Damage


The retina plays an essential role in preventing blindness. WebMD shows that when blue light penetrates through the lens and to the retina, it may cause retina photochemical damage, A.K.A. phototoxicity. Blue light can also accelerate age-related macular degeneration (AMD) after cataract surgery, according to the International Journal of Opthalmology.


Other Health Impacts


Blue light has often been associated with poor sleeping quality. Usually, when it gets dark, the pineal gland secretes melatonin, making us feel tired and sleepy. Therefore, during nighttime, exposure to blue light disrupts our natural sleeping rhythm as it tricks our brain to think it is daytime. Consequently, people take longer to fall asleep, their circadian clock can be delayed, and they may be less alert the following day, describes Brigham Health Hub. Sleep deprivation can cause various health risks such as heart disease, obesity, cancers, and other mental impacts. You can find more about sleep deprivation’s effects on the brain in our article.


How Can We Limit Blue Light Exposure?


Ever since the beginning of the COVID-19 pandemic, the usage of digital devices has surged across the globe. Youth are using their computers rather than going to school while adults are working at home for more than a year. An Indian Journal of Opthalmology study shows that 93.6% of 407 respondents reported an increase in screentime with the total usage per day of 8.65 hours or even more. Unfortunately, 95.8% have also experienced at least one symptom related to digital usage.


Image is courtesy of the Indian Journal of Opthalmology.


In this situation, it is difficult to avoid the usage of digital devices, but it's important to find ways to minimize their adverse effects.


20-20-20 Rule


We are always told not to look at the screen too close since we are small. The Canadian Association of Optometrists suggests that every 20 minutes, you should take a 20-second break and focus your eyes on something at least 20 feet away. If you struggle to do so, set a timer or a Pomodoro method to remind yourself.


Blue Light-Blocking Glasses


There has been a controversial debate about the effectiveness of blue-light-blocking glasses. Ophthalmologist Dr. Singh from the Cleveland Clinic says that experiencing digital eye strain is caused by the way people use the screen, not essentially the blue light per se. So far, there has not been a lot of research done on these new glasses. Dr. Mark Rosenfield, a professor at State University of New York (SUNY) College of Optometry, conducted two studies in 2019 and 2020 demonstrating that blue-light blocking glasses posed no evidence of preventing digital eye strain.


Regarding sleeping quality, there are a few studies that find that blue-light glasses improve sleep and productivity. A 2017 study by the University of Houston discovered that participants increased melatonin production and increased sleeping time. Nevertheless, there is still a lack of high-quality evidence. The American Academy of Ophthalmology believes that it is not necessary to purchase special eyewear for computer use. Simply decreasing evening screen time and changing device settings is sufficient.


Changing Device Settings


The standard way to do this is to change the settings on your device directly. On an Apple device, go to Settings, then Display & Brightness, and tap the night shift setting, altering the screen temperature to a warmer colour. This function allows you to adjust the colour so that you can find the right temperature balance. It can also set time zones or scheduled times. If you use an Android device, go to Settings and Display & Brightness to turn on the night light or blue light filter. Adjust the Opacity option to change the colour temperature and schedule when to turn it on.


Another popular way to reduce the detrimental effects of screens is to install a program called f.lux on the computer. It automatically adjusts colour and brightness on the screen based on the timezone. At night, it shifts to an amber/red colour to reduce blue light exposure.


Avoid Using Devices Before Bed


Despite the advanced method mentioned above, the National Sleep Foundation recommends that you stop using electronic devices at least 30 minutes before bedtime. Instead, develop a new bedtime routine such as reading or stretching. This may help your brain develop a sleeping mode to improve sleeping quality.


Overall, we can never avoid blue light both from natural sources and artificial sources. However, it is vital to reduce screen time and exposure in order to protect your eyes and improve sleep quality. Remember to take frequent breaks if school or work involves long hours of screen time, and we hope you have a good night's sleep.



Article author: Michelle Lam

Article editors: Valerie Shirobokov, Stephanie Sahadeo