Work Text:
Diana Cavendish is a good student.
Well, she's actually far more than a 'good student', but it's a nice, concise way to summarize it.
So, being a 'good student', no one would be surprised if they knew she enjoyed researching in her free time. They would however be surprised to find out that she often did not research topics in the magical world.
While Diana definitely could write incredible papers on any topic in the magical world, enough of her studies are swallowed in it, and writing papers was her idea of fun. It would be far less fun for her to write papers on her studies. Instead, she enjoys researching outside of the magical world, focusing on any topic that picks up her fancy.
Her latest project started when she ran into Akko while on patrol. The little energizer had been awake at midnight, sneaking into the kitchen to steal pastries. After she had reprimanded her (Reprimanded, really reprimanded. She was not soft on Akko, no matter what anyone says. Especially Amanda.), Akko had, for the first time, came back with an excuse. That being that her phone 'was being mean to her' and 'causing her to stay awake'. The idea stuck with her after she had escorted Akko back to her dorms (Not. Soft.), and throughout the next day. Cellular devices causing insomnia? It seemed rather... farfetched, but then again, the more farfetched an idea was, the less likely it was that Akko was making it up.
So, she started researching. It was exciting, at first, to see some results instantly. But... the media coverage she found seemed quite minimal with further investigation. There wasn't any coverage on any magic-related media either... which really was quite disappointing. Young students, studying magic or not, needed to understand how dangerous their devices really could be. Diana found herself quite concerned for the health of her peers. As such, a paper was in order.
Not one specific peer, peers. She was not writing an entire research paper for Akko. She was not. However it would be pertinent to have her read the paper... though knowing Akko she likely wouldn't be able to get far before getting distracted. Maybe Diana could read it to her then? She could make a study session for it, sit in the library with her, read her research and answer any question she may have... teach her all of the ins and outs of the subject... pet her hair as she sat in her-
Ahem.
The important thing is that she wrote it for everyone, not just one, very cute, very hyper, very very...
EVERYONE. For everyone to read, research for themselves, and learn from.
Now, the paper had finally reached a state of completion. Diana had reviewed it her normal 10 times for mistakes, had it peer reviewed once thus far, and was waiting on 4 other reviews. A project well done. However... she did write and review a decent chunk of the paper while on... let's say minimal sleep. Another review couldn't hurt, could it?
Closing the 30 tabs of research she had open, Diana began to read over her review.
The Effects of Electronically-Emitted Blue Light on Student’s Circadian Rhythm and Day to Day Life: A Review
Diana Cavendish
Luna Nova Magical Academy
December 15 th , 2021
Abstract
Electronically-emitted blue light is light in the visible spectrum emitted from light-emitting diodes (LEDs), and ranges between 400 and 490 nanometers. Blue light is linked with the regulation of the circadian rhythm via regulating the secretion of melatonin. To provide a deeper understanding of the effects of electronic blue light on students' sleep and health, numerous studies were analyzed. The final conclusion of this review is that electronically-emitted blue light exposure during dark/sleeping hours results in a decrease in metabolic function, a higher risk of diabetes, and reduced cognitive function. Certain studies also suggest a risk of severe retinal damage as well. The limitations of this review are discussed and any suggestions for further research are given.
Keywords: Blue light, circadian rhythm, melatonin, Light-emitting diode, LED, sleep, retinal damage, retina, diabetes, metabolism
The Effects of Electronically-Emitted Blue Light on Student’s Circadian Rhythm and Day to Day Life: A Review
Introduction
Through the past few decades, technology has been advancing at an increasing rate. While the magical world has yet to see an increased usage of technology in it’s instruction modality, new innovations have led to the vast majority of young students to be reliant on technology for work, education, and more. As technology use rises, the amount of time spent staring at a screen per day does as well [1].
...Was that too casual of a way to say it? There must be a better way of communicating the same thought. Maybe 'The ascent of technology use has simultaneously caused a significant increase in time spent looking at a screen per day'? Mmmmmm... yes that sounds better.
The ascent of technology use has simultaneusly caused a significant increase in time spent looking at a screen per day [1]. To cite a recent example, a team of researchers from the Pravara Institute of Medical Sciences in Loni, Ghaziabad, India observed how device usage at bed-time affected quality of sleep, as well as the extent of blue light exposure from student to student [2]. They observed that students were commonly spending time on blue-light emitting devices during their regular sleeping hours, and that increased device usage resulted in a significant decrease in sleep quality, reduced sleep duration, and overall cognitive dissonance [2]. Adverse effects are not just limited to these findings, and can also include increased risk to disease, decreased metabolic function, and possible severe retinal damage [3-7].
Hmmmm, this line feels too... something. Not Right. 'Adverse effects are not just...', maybe 'The effects of blue light are'? No, no, that doesn't work.
Damn... damn damn.
Maybe add a 'However'?
'However, adverse effects...'
That feels better.
However, adverse effects are not just limited to these findings, and can also include increased risk to disease, decreased metabolic function, and possible severe retinal damage [3-7]. Research on blue light side effects and prevention has increased over the years, yet still lacks in some areas [2-7]. As such, this review aims to collect and review recent research, investigate the effects of increased blue light exposure, and suggest topics for further exploration. Background on blue light and other general information will be presented first, followed by effects of electronically-emitted blue light exposure during late hours, and prevention methods. The literature chosen as well as reasons for selection is found in table 1. The limitations of studies and this review will be analyzed in closing.
Table 1: Summary and modalities of selected literature
Background Information on Blue Light and the Circadian Rhythm
In humans, blue light (light falling between 400 nanometers and 490 nanometers on the visible spectrum) regulates the secretion of melatonin, a hormone that regulates sleep [8]. In natural settings,
That feels like far too much of an elementary of a way to transition into that idea...
Add the sun part to the beginning, then...
A human is naturally exposed to blue light from the sun during the day, halting melatonin secretion and keeping them alert and awake. Then, once exposure decreases at night, melatonin is secreted to induce drowsiness [8,9]. This cycle is commonly known as the circadian rhythm, or the sleep-wake cycle. While this is a natural process, the body is not capable of differentiating between natural blue light and artificial blue light. A 2019 study demonstrated this by exposing 20 individuals to artificial blue light during nighttime hours. It was found that subject’s melatonin levels were decreased during exposure (Figure 1), and awareness was increased for an extended duration [3].
Figure 1: Individual melatonin profiles 2 h prior to, during (boxed area) and 4 h after 6.5 h exposure to 17,000 K (Blue-spectrum light) and 4000 K (White-spectrum light) light, normalized to each individuals' fitted peak value during the first melatonin cycle on CR1 [3].
These significant decreases in melatonin production during nighttime hours can lead to a lack of sleep, and a disruption in the normal circadian rhythm [3]. While this study uses a more general context and population, an aforementioned 2020 study [2]
Is this the correct way I should word this? Or do I rewrite the introduction of the study? I really need to read that textbook again.
I have a few other texts I need to review, so I'll have to make a day trip to the library. It's always so dull when I'm there on my own for long hours, though. Maybe I could convince Akko to join me...
focused on medical undergraduate students, seeking to measure the usage of smartphones (a common source of electronic blue light) and the subsequent effect on quality and quantity of sleep [2]. The study found that students with an increased level of smartphone usage exhibited in creased sleep latency, reduced sleep duration, sleep inefficiency, and increased daytime sleep disturbances [2].
Ending the section on just that feels odd but... I really am incapable of thinking of a better way to do it without making it sound forced. I suppose this will do for now.
How Shifts in the Circadian Rhythm Affect Health
A shift in the circadian rhythm is defined as when melatonin secretion is delayed outside of the natural sleep wake schedule [1,3,4,8-11]. As discussed above [2], the result of such a shift can be a lack of adequate sleep, sleep inefficiency, and daytime drowsiness [2]. However further research suggests that these are not the only possible effects [1,4-7]. In a 2012 clinical trial, 24 healthy adults underwent controlled circadian disruptions and sleep deprivation and saw effects Participants exhibited
Ah... that's slipped through the cracks. I really should get some sleep sometime soon...
In a 2012 clinical trial, 24 healthy adults underwent controlled circadian disruptions and sleep deprivation over the course of 39 days following a controlled sleep period. Participants exhibited a decreased metabolic rate, a relative reduction in insulin secretion (possibly due to inadequate pancreatic beta cell response) and an increase in postprandial glucose (glucose in plasma after a meal) [1]. This suggests is that there exists links between circadian shifts and sleep deprivation, decreased metabolic activity, as well as increased risk of diabetes, as increased postprandial glucose and decreased insulin secretion is indicative of diabetes [1,4]. The trial closed with a 9 day period of recovery, during which metabolic activity, postprandial glucose levels, and insulin secretion all normalized [1]. This suggestion can be further evidenced by a 2019 study that had participants use blue light blocking lenses 2-3 hours before they went to sleep over the course of the month. During the month that participants wore these lenses, significant improvements in insulin resistance was observed (Figure 2) [4].
Figure 2: Clinical parameters after wearing blue-light shield glasses at night. Blue-light shield eyewear is shown in (A). Glucose metabolism including fasting plasma glucose (B), fasting insulin (C), and C peptide (D) before and after 1-month use of blue-light shield eyewear at night was measured. Fasting plasma glucose decreased significantly. HOMA-β (E) and HOMA-IR (F) before and after 1-month use of blue-light shield eyewear at night were also measured, with HOMA-IR showing significant decreases. Lipid metabolism including triglyceride (G), HDL-ch (H), and LDL-ch (I) levels before and after 1-month use of blue-light shield eyewear at night are shown. Liver function including ALT (J) and AST (K) before and after 1-month use of blue-light shield eyewear at night was observed, with significant increases in AST. Subjective sleep quality (assessed with PSQI) (L) and depression (assessed with CES-D) (M) were assessed before and after 1-month use of blue-light shield eyewear at night. There were significant improvements in PSQI. *P < 0.05, paired t-test [4].
Blue Light and Eye Damage
The effects of blue light on the human retina is not yet fully understood, and having become a concern only in the past decade, there is not a lot of research supporting the topic. However, from what studies that have been conducted, it is known that there does exist possible links between blue light and photoreceptor cell death [5,6]. One example of blue light promoting apoptosis in photoreceptor cells was seen in a 2014 study, where photoreceptor cells were exposed under blue, white, and green light. Out of the different wavelengths, the cells under blue light (450 nm to 495 nm in the context of the trial) showed the most significant retinal damage, greatly reducing cell viability (Figure 3) [5]. These cells also saw an increase in reactive oxygen species (ROS), which is induced by photoreceptor cell death (Figure 3) [5]. A 1985 study that exposed albino rats to high-intensity fluorescent light at different times of day was chosen to supplement the information from this trial [6]. While this was an older source of information, the results were irrefutably valuable in the context of this review. The trial concluded that the retinas of rats exposed during the dark/nighttime period were significantly more damaged than rats exposed during light/daytime periods [6]. This opens the suggestion that increased blue light exposure specifically at night could possibly mean significantly increased retinal damage. With context of the discussion thus far [1-6,8,10-12], it can be concluded that students using cellular devices during sleeping hours could be the most at-risk for significantly increasing their risk of photoreceptor and retinal damage [5,6].
Figure 3: (A) The exposure of blue, white, and green LED light to cells cultured in a 96-well plate. (B) The observation of cell morphology using bright field microscopy, showing blue LED light caused the morphological changes compared with the control. Green LED light did not change the cells. (C–E) The quantitative evaluation of cell viability by the CCK-8 assay. This result is consistent with the observed change in cell morphology. Cell viability was reduced by blue and white LED light exposure, but not green LED light. The scale bar represents 50 μm. Data are expressed as mean ± SEM (n = 6). ## indicates p < 0.01 vs. control (ANOVA) [6].
Preventative Measures
As we have thus far discussed [1-6,8,10-12], increased exposure to blue light during sleeping hours can lead to a plethora of negative effects on human metabolism and eye health. This raises the question, how can this be prevented?
Putting questions in my papers never fails to feel off. I could probably word this better.
Avoiding the question feels like the best solution.
While one may suggest not allowing blue light exposure during nighttime hours, the reality is not so simple. Many people cannot avoid working on their devices late at night, and as such raises the need for an active solution for exposure. One very simple solution is the usage of amber blue light blocking lenses [4,7,9,11,12]. This modality of prevention is backed with significant amounts of clinical trials, and has thus far proven to be effective [4,7,9,11,12]. In one 2018 study, individuals with insomnia were provided with amber blue light filtering lenses to wear for 2 hours immediately preceding bedtime, and significant improvements in sleep quality and duration were observed [11]. A second study in 2019 that examined the metabolic effects of blue light used similar methods and saw significant improvements in sleep quality as well as healthy metabolic activity in participants [4]. A third trial in 2021 used similar methods with managers and employees of a call center, and observed improvements in sleep, work engagement, and task performance [12]. This study also observed that improvements were more significant for employees who, on average, had sleep periods that were later in the day [12]. Based on these results, it can be concluded that the usage of blue light blocking lenses is very effective in significantly reducing or outright eliminating the adverse effects of blue light exposure late at night [4,11,12 ].
That feels so... redundant to say. Is there a better way to express the idea? Maybe...
These study's results lead to the conclusion that the usage of blue light blocking lenses is very effective in significantly reducing or outright eliminating the adverse effects of blue light exposure late at night [4,11,12 ].
Mhm, yes, better.
However, there do exist other solutions that have seen research over the years [7,13,14 ]. One randomized controlled trial in 2011 sought to reduce asthenopia (eye strain) in adults via the usage of fish oil, bilberry extract, and lutein supplements [13]. 11 participants in the active group took the supplements for 4 weeks, and saw improvements in critical symptoms of asthenopia (eye fatigue and a “stuffy head) as well as mental fatigue [13]. A second study in 2017 provided participants with Lutein and Zeaxanthin over the course of a year. During this time period, it was found that cognitive function among the active group was improved [14]. While this is a far more indirect and symptom-focused method of prevention, it is worth further investigation. Another method that has seen research is the usage of intraocular lenses to block blue light. Intraocular lenses in humans are commonly used as solutions for cataracts of myopia, and are a far more permanent treatment [7]. In a 2009 clinical trial, blue light filtering intraocular lenses (IOL) were used to filter light above human retinal pigment epithelium (RPE) cells, and found that blue light filtering IOLs were effective in significantly reducing cell damage, suggesting that the usage of blue light filtering IOLs may prevent retinal damage in clinical use [7]. IOLs are, essentially, permanent blue light filters. The invasiveness of this method makes it a far less attractive option, and only applicable in very specific contexts. Research would likely be better spent on the less invasive options.
I both like and hate that sentence. It feels so... abrupt. But, I suppose being abrupt and upfront is in the nature of this type of research.
Conclusion
Blue light exposure has become an increasingly pertinent issue in recent years. Media coverage has been limited, and as such the common person does not fully understand the full risks of regular device usage during night hours. While blue light in humans is naturally meant to regulate and maintain a healthy circadian rhythm, the increased usage of blue-light emitting electronic devices has changed the regular exposure to blue light. Currently, the majority of literature investigating blue light’s exposure during regular dark/sleeping hours is testing the effects on sleep and metabolic activity, and generally concludes that effects include sleep deprivation, cognitive dissonance, decreased metabolic health/activity, and an increased risk of diabetes. Literature studying blue light’s effects on retinal health on the other hand is limited, and primarily rests in cellular research, without any clinical trials with humans. Therefore there still remains a quandary as to the true severity of blue light exposure on the human retina. There does exist strong evidence pointing in the direction of this quandary, and as such is a field where further research should be considered. The prevention methods for blue light exposure is a very well researched and supported field. The vast majority of research points towards the simple solution of blue-light blocking lenses (glasses) or filters applicable during night hours, as well as dietary supplements being an option for prevention of side effects. There is some evidence for other methods of reducing symptoms or blocking blue light, but it is highly experimental and is invasive, as well as likely unnecessary. Further research into other options is therefore suggested. With the understanding that technology use will increase an incredible amount in our very near future, we must attempt to further understand the facets and byproducts of this increase. Creating a sufficient understanding of blue light and its effect on humans is critical to maintaining the continued health and well-being of current and future generations.
Should I really end this paper like this? Maybe I've confused myself... I've made a half review and half narrative paper...
A narrative review. Ah, that's an actual thing isn't it? Then, I've made a half narrative review, half argumentative essay. How annoying.
This one will go to the discussion boards, then. Extensive peer review is in order.
And only now do I realize the irony in writing research on blue light at night and lack of sleep, while doing everything I wrote I shouldn't... I should take my own advice sometime.
References
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- Krishnan B, Sanjeev RK, Latti RG. Quality of Sleep Among Bedtime Smartphone Users. Int J Prev Med. 2020 Aug 6;11:114. doi: 10.4103/ijpvm.IJPVM_266_19. PMID: 33088442; PMCID: PMC7554597.
- Hanifin JP, Lockley SW, Cecil K, West K, Jablonski M, Warfield B, James M, Ayers M, Byrne B, Gerner E, Pineda C, Rollag M, Brainard GC. Randomized trial of polychromatic blue-enriched light for circadian phase shifting, melatonin suppression, and alerting responses. Physiol Behav. 2019 Jan 1;198:57-66. doi: 10.1016/j.physbeh.2018.10.004. Epub 2018 Oct 5. PMID: 30296404.
- Nagai N, Ayaki M, Yanagawa T, Hattori A, Negishi K, Mori T, Nakamura TJ, Tsubota K. Suppression of Blue Light at Night Ameliorates Metabolic Abnormalities by Controlling Circadian Rhythms. Invest Ophthalmol Vis Sci. 2019 Sep 3;60(12):3786-3793. doi: 10.1167/iovs.19-27195. PMID: 31504080.
- Kuse Y, Ogawa K, Tsuruma K, Shimazawa M, Hara H. Damage of photoreceptor-derived cells in culture induced by light emitting diode-derived blue light. Sci Rep. 2014;4:5223. Published 2014 Jun 9. doi:10.1038/srep05223
- Duncan TE, O'Steen WK. The diurnal susceptibility of rat retinal photoreceptors to light-induced damage. Exp Eye Res. 1985 Oct;41(4):497-507. doi: 10.1016/s0014-4835(85)80007-5. PMID: 4085578.
- Kernt M, Neubauer AS, Liegl R, Eibl KH, Alge CS, Lackerbauer CA, Ulbig MW, Kampik A. Cytoprotective effects of a blue light-filtering intraocular lens on human retinal pigment epithelium by reducing phototoxic effects on vascular endothelial growth factor-alpha, Bax, and Bcl-2 expression. J Cataract Refract Surg. 2009 Feb;35(2):354-62. doi: 10.1016/j.jcrs.2008.10.052. PMID: 19185255.
- Touitou Y, Touitou D, Reinberg A. Disruption of adolescents' circadian clock: The vicious circle of media use, exposure to light at night, sleep loss and risk behaviors. J Physiol Paris. 2016 Nov;110(4 Pt B):467-479. doi: 10.1016/j.jphysparis.2017.05.001. Epub 2017 May 12. PMID: 28487255.
- Burkhart K, Phelps JR. Amber lenses to block blue light and improve sleep: a randomized trial. Chronobiol Int. 2009 Dec;26(8):1602-12. doi: 10.3109/07420520903523719. PMID: 20030543.
- Wahl S, Engelhardt M, Schaupp P, Lappe C, Ivanov IV. The inner clock-Blue light sets the human rhythm. J Biophotonics. 2019 Dec;12(12):e201900102. doi: 10.1002/jbio.201900102. Epub 2019 Sep 2. PMID: 31433569; PMCID: PMC7065627.
- Shechter A, Kim EW, St-Onge MP, Westwood AJ. Blocking nocturnal blue light for insomnia: A randomized controlled trial. J Psychiatr Res. 2018 Jan;96:196-202. doi: 10.1016/j.jpsychires.2017.10.015. Epub 2017 Oct 21. PMID: 29101797; PMCID: PMC5703049.
- Guarana CL, Barnes CM, Ong WJ. The effects of blue-light filtration on sleep and work outcomes. J Appl Psychol. 2021 May;106(5):784-796. doi: 10.1037/apl0000806. Epub 2020 Jul 13. PMID: 32658494.
- Kawabata F, Tsuji T. Effects of dietary supplementation with a combination of fish oil, bilberry extract, and lutein on subjective symptoms of asthenopia in humans. Biomed Res. 2011 Dec;32(6):387-93. doi: 10.2220/biomedres.32.387. PMID: 22199129.
- Renzi-Hammond LM, Bovier ER, Fletcher LM, Miller LS, Mewborn CM, Lindbergh CA, Baxter JH, Hammond BR. Effects of a Lutein and Zeaxanthin Intervention on Cognitive Function: A Randomized, Double-Masked, Placebo-Controlled Trial of Younger Healthy Adults. Nutrients. 2017 Nov 14;9(11):1246. doi: 10.3390/nu9111246. PMID: 29135938; PMCID: PMC5707718.
The references all seemed in order and accurate to Diana, no research missing, no citations gone un-cited... a few corrections on the communication of ideas and it would be ready to publish.
Diana quickly navigated to the review forums she frequented, posting a quick request for the latest version of her paper. All that was left now was to wait a few days for a proper amount of reviews, then finalize and post.
Maybe she could set up those study session with Akko in the meantime...