Should we avoid blue light?

by Gagandeep Munday

The black mirrors that we gaze into every day provide an illuminating source of information and entertainment.  Over the past few decades these devices have changed the way we work and the way we relax. They are an important part of our lifestyle. Consequently, we are bombarded by artificial blue light whenever we utilize our computers, stare at our phones/tablets, or watch TV. Recently, android and apple devices have introduced a built-in feature called “night mode” which reduces the amount of blue light emitted during evening hours1,2. A phone screen displaying a warmer spectrum of light is said to have less of an effect on our eyes2. Is there any basis for this assertion? Should we really avoid this spectrum of light at night? What are the benefits and consequences of exposure to blue light at night?

The sun is a natural source of bright light and it contains blue light3. Out of all the colors in the bright light spectrum, blue light has the largest effect on our sleep cycle8. Daytime exposure to blue light is said to regulate the human 24-hour circadian rhythm and provides photosensitive cues to our brain that we are supposed to be awake4,5,6. This is accomplished by activation of the melanopsin receptor in the retina and downstream inhibition of the hormone melatonin’s secretion by the pineal gland5,9. Ophthalmology researchers have also speculated that decreased exposure to blue light during the day could have a negative effect on circadian rhythm4,6. In addition, sleep medicine researchers have ascertained that even the sleep cycles of blind people with intact eyes are affected by exposure to bright light, which as mentioned earlier contains blue light7. Therefore, there have been concerns that the disruption of the circadian rhythm at night by artificial sources of blue light can lead to a variety of problems such as decreased alertness, decreased performance at work/school, and tragic traffic accidents.

When we are working late or using our phones late into the night, we are preventing ourselves from getting the rest that we need. This is partly attributed to disruption of circadian by the blue light emitted from screens. In one study, over 60% of young adult students reported use of cell phones when they were supposed to be asleep11. In another study, young adults reported 3-5 hours of smart phone use after their projected bed time14. This resulted in insomnia, fatigue, and headaches11. A combination that is suspected to negatively influence academic performance. Overall, lack of sleep has been shown to negatively impact cognitive performance13. This is such a pertinent issue for young adults, whose prime years are impacted and possibly put in harm. Some studies speculate that excessive smartphone usage can lead to psychological issues in young adults20,21. However, the danger is not just at home. According to the NHTSA there were 91,000 crashes in 2017 due to drowsy driving, of which 795 were fatal10. The organization notes concern for teenagers, indicating that they are not getting enough sleep10. In all, adult drivers with a disrupted circadian rhythm remain a bigger area of concern because it said to mimic alcohol-impaired driving12.

Due to the ubiquitous presence of blue light and its potent effects on increasing alertness and suppressing biological sleep mechanisms, there have been some developments to maximize on potential benefits for while mitigating perceived harms. Blue light filtering spectacles have been shown to reduce the blue light transmission and lead to substantial improvements in visual performance and in quality of sleep16,17. Further studies have indicated that reduction of blue light transmission can lead to a marked decrease in adrenocortical hormone production, the stress hormone8,18,19. A study involving adolescent males from the age of 15-17 indicated that wearing blue light-blocking glasses favored sleep initiating mechanisms25. Similarly, smart phone blue light filters have been shown to offer similar effects as glasses18,22,23. Smartphone blue light filters can reduce visual fatigue and improve visual performance in certain tasks24. In all, through these methods there seems to be marked effort to mitigate the harmful effects of too much screen time while promoting “safe screen use”. While there is a reduction in blue light transmission and improvement in sleep quality that still does not mean that detrimental effects of prolonged exposure are eliminated.

On the other hand, exposure to blue light is beneficial during the period in which you are expecting to be awake. Studies have shown that bright light rich in blue light might be particularly potent in reducing depression and other mood maladies 8,16. An experiment involving exposure to 30 mins of blue light, has shown enhancement in cognitive performance26. Similarly, a longitudinal study involving 44 adults indicated that a blue light environment leads to subjective alertness, lower sleepiness, and objectively measurable cognitive performance enhancement28. In all, exposure to blue light can be beneficial unless you are trying to sleep.

This overview of the issue suggests that there needs to be further research into this topic and there also needs to be a public service campaign to raise awareness. The prevalence of multimedia usage in the evening is particularly high among adolescents and young adults. Research has made it clear when we shouldn’t be exposing ourselves to blue light during that time of the day. Prolonged exposure to blue light at night is suspected to have physical and psychological effects on young adults. What I recommend is a series of laws and social changes that reduce the amount of exposure. First, highways and intersections should be lit with blue light enriched lights in order to promote alertness and to decrease sleepiness on the road. This is a costly measure and it could also have some negative effect on the natural landscape. Research would be needed to be conducted in order to determine the effects of blue lighting on animals and greenery. Secondly, all smartphones, tv screens, tablets, and computers should come in with a built-in blue light filter. Laws mandating these changes would have a marked effect on the level of exposure to blue light. Many blue light filter apps are free and should come standard with all devices. The user should retain the power to set the filter depending on their own schedule. Thirdly, there should be public campaigns that help enlighten the public about the effects of prolonged blue light. Letters should be sent by public schools to parents about limiting screen exposure. Clinicians should warn parents of potential harms about prolonged screen usage. Public service announcements should be made about the connection between blue light exposure and lack of sleep. These suggestions are not extremely costly. In summation, further research would enlighten the public about the detriments of late-night blue light exposure. As of right now researchers have found a significant connection between blue light exposure and the detriments associated with the disruption of the circadian rhythm.

Sources:

  1. https://www.androidauthority.com/blue-light-filters-1067108/
  2. https://support.apple.com/en-us/HT207570
  3. O’Hagan JB, Khazova M, Price LL. Low-energy light bulbs, computers, tablets and the blue light hazard. Eye. 2016;30(2):230-3. PubMed Central PMCID: PMCPMC4763136. doi: 10.1038/eye.2015.261 26768920
  4. Mainster MA, Turner PL. Blue-blocking IOLs decrease photoreception without providing significant photoprotection. Surv Ophthalmol. 2010;55(3):272-89. doi: 10.1016/j.survophthal.2009.07.006 19883931
  5. Viola AU, James LM, Schlangen LJ, Dijk DJ. Blue-enriched white light in the workplace improves self-reported alertness, performance and sleep quality. Scand J Work Environ Health. 2008;34(4):297-306. 18815716
  6. Mainster MA. Intraocular lenses should block UV radiation and violet but not blue light. Archives of ophthalmology. 2005;123(4):550-5. doi: 10.1001/archopht.123.4.550 15824232
  7. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0169114
  8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2831986/
  9. https://link.springer.com/article/10.1007%2Fs004410050579
  10. https://www.nhtsa.gov/risky-driving/drowsy-driving
  11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4733306/
  12. https://www.nhtsa.gov/sites/nhtsa.dot.gov/files/drowsydriving_strategicplan_030316.pdf
  13. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2656292/
  14. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6191085/
  15. Chiu, Hsiao‐Ping, and Chien‐Hsiou Liu. “The Effects of Three Blue Light Filter Conditions for Smartphones on Visual Fatigue and Visual Performance.” Human Factors and Ergonomics in Manufacturing & Service Industries, vol. 30, no. 1, 2020, pp. 83–90.
  16. https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0169114
  17. https://go-gale-com.york.ezproxy.cuny.edu/ps/i.do?id=GALE%7CA476237340&v=2.1&u=cuny_york&it=r&p=HWRC&sw=w
  18. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6288536/
  19. https://www.hindawi.com/journals/ije/2010/829351/
  20. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5802650/?report=reader
  21. https://link.springer.com/article/10.1007%2Fs00038-011-0234-z
  22. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5854379/
  23. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6280115/
  24. https://onlinelibrary.wiley.com/doi/pdf/10.1002/hfm.20824
  25. https://www.jahonline.org/article/S1054-139X(14)00324-3/fulltext
  26. Meesters, Ybe, et al. “The Effects of Low-Intensity Narrow-Band Blue-Light Treatment Compared to Bright White-Light Treatment in Seasonal Affective Disorder.” Journal of Affective Disorders, vol. 232, 2018, pp. 48–51.
  27. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4989256/
  28. https://link.springer.com/article/10.1007%2Fs00702-006-0621-4

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