Biology:Biological effects of high-energy visible light

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Short description: Blue-light toxicity
Blue light, a type of high-energy light, is part of the visible light spectrum

High-energy visible light (HEV light) is short-wave light in the violet/blue band from 400 to 450 nm in the visible spectrum, which has a number of purported negative biological effects, namely on circadian rhythm and retinal health (blue-light hazard), which can lead to age-related macular degeneration.[1][2] Increasingly, blue blocking filters are being designed into glasses to avoid blue light's purported negative effects. However, there is no good evidence that filtering blue light with spectacles has any effect on eye health, eye strain, sleep quality or vision quality.[3]

Background

Blue LED light

Blue LEDs are often the target of blue-light research due to the increasing prevalence of LED displays and Solid-state lighting (e.g. LED illumination), as well as the blue appearance (higher color temperature) compared with traditional sources. However, natural sunlight has a relatively high spectral density of blue light, so exposure to high levels of blue light is not a new or unique phenomenon despite the relatively recent emergence of LED display technologies. While LED displays emit white by exciting all RGB LEDs, white light from lighting is generally produced by pairing a blue LED emitting primarily near 450 nm combined with a phosphor for down-conversion of some of the blue light to longer wavelengths, which then combine to form white light. This is often considered “the next generation of illumination” as SSL technology dramatically reduces energy resource requirements.[4]

Luminous efficiency

Blue LEDs, particularly those used in white LEDs, operate at around 450 nm, where V(λ)=0.038.[5][6] This means that blue light at 450 nm requires about 25 times the radiant flux (energy) for one to perceive the same luminous flux as green light at 555 nm. For comparison, UV-A at 380  nm (V(λ)=0.000 039) requires 25 641 times the amount of radiometric energy to be perceived at the same intensity as green, three orders of magnitude greater than blue LEDs.[7][8] Studies often compare animal trials using identical luminous flux rather than radiance meaning comparative levels of perceived light at different frequencies rather than total emitted energy.[9][10]

Physiological effects

Blue light hazard

A 2019 report by France's Agency for Food, Environmental and Occupational Health & Safety (ANSES) highlights short-term effects on the retina linked to intense exposure to blue LED light, and long-term effects linked to the onset of age-related macular degeneration.[11] Although few studies have examined occupational causes of macular degeneration, they show that long-term sunlight exposure, specifically its blue-light component, is associated with macular degeneration in outdoor workers.[12] However, the CIE published its position on the low risk of blue-light hazard resulting from the use of LED technology in general lighting bulbs in April 2019.[13]

The international standard IEC 62471 assesses the photobiological safety of light sources.[14] A proposed standard, IEC 62778, provides additional guidance in the assessment of blue-light hazard of all lighting products.[15]

Circadian rhythm

Main page: Biology:Circadian rhythm

The circadian rhythm is a mechanism that regulates sleep patterns. One of the primary factors affecting the circadian rhythm is the excitation of melanopsin, a light sensitive protein that absorbs maximally at 480 nm, but has at least 10% efficiency in the range of 450-540 nm.[16] The periodic (daily) exposure to sunlight generally tunes the circadian rhythm to a 24-hour cycle. However, exposure to light sources that excite melanopsin in the retina during nighttime can interfere with the circadian rhythm. Harvard Health Publishing asserts that exposure to blue light at night has a strong negative effect on sleep.[17] The aforementioned ANSES report "highlights [the] disruptive effects to biological rhythms and sleep, linked to exposure to even very low levels of blue light in the evening or at night, particularly via screens".[18] A 2016 press release by the American Medical Association concludes that there are negative effects on the circadian rhythm from the unrestrained use of LED street lighting and white LED lamps have 5 times greater impact on circadian sleep rhythms than conventional street lamps.[19] However, they also indicate that street lamp brightness is more strongly correlated to sleep outcomes.

Blue light is essential for regulating the circadian rhythm, because it stimulates melanopsin receptors in the eye.[20] This suppresses daytime melatonin, enabling wakefulness. Working in blue-free light (aka yellow light) for long periods of time disrupts circadian patterns because there is no melatonin suppression during the day, and reduced melatonin rebound at night.

Eye strain

Blue light has been implicated as the cause of digital eye strain, but there is no robust evidence to support this hypothesis.[21][22]

Dermatology

As with other types of light therapy, there is no good evidence that blue light is of use in treating acne vulgaris.[23][24]

Blue light blocking

Concerns over exposure to blue light has predicated several solutions to decreasing blue light exposure, including disabling or attenuating blue LEDs in displays, color shifting displays towards yellow, or wearing glasses that filter out blue light.

Digital filters

Apple's and Microsoft's operating systems and even the preset settings of standalone computer monitors include options to reduce blue-light emissions by adjusting color temperature to a warmer gamut.[25][26] However, these settings dramatically reduce the size of the color gamut of the display, as they essentially simulate tritan color blindness, thereby sacrificing the usability of the displays. The filters can be set on a schedule to activate only when the sun is down.

Intraocular lenses

During cataract surgery, the opaque natural crystalline lens is replaced with a synthetic intraocular lens (IOL). The IOL may be designed to filter out equal, more or less UV light than the natural lens (have a higher or lower cutoff), and therefore attenuate or accentuate the blue-light hazard function. The effects of long term exposure of UV, violet and blue light on the retina can then be studied.[27] However, it has been argued that IOLs that remove more blue light than natural lenses negatively affect color vision and the circadian rhythm while not offering significant photoprotection.[28] Systematic reviews found no evidence of any effect in IOLs filtering blue light,[29] and none provided any reliable statistical evidence to suggest any effect regarding contrast sensitivity, macular degeneration, vision, color-discrimination or sleep disturbances.[30] One study claimed a large difference in observed fluorescein angiography examinations and observed markedly less "progression of abnormal fundus autofluorescence"; [31] however the authors failed to discuss the fact that the excitation beam is filtered light between 465 and 490 nm,[32] is largely blocked by blue light filtering IOLs[33] but not clear IOLs present in the control patients.

Blue light blocking lenses

Lenses that filter blue light have been on the market for a long time in the form of brown-, orange-, and yellow-tinted sunglasses.[34] These tinted lenses were popular for the belief that they enhanced contrast and depth perception, but after early research showing the health risks of blue light exposure,[35][36] became more popular for the purported health benefits of blocking blue light.[37]

The efficacy of blue-blocking lenses in blocking blue light is not disputed, but whether typical exposure to blue light is hazardous enough to require blue blocking lenses is highly disputed.[38] One problem with the glasses is that they cannot achieve positive outcomes in blue-light hazard and sleep simultaneously. To be effective in against blue-light hazard, the glasses must be worn continuously, especially during the day when exposure is higher. However, to force blue-light exposure that mimics the normal daylight cycle, the glasses must only be worn at night, when the exposure is already quite low from a photoprotective perspective. Regardless, some evidence shows that lenses that block blue light may be particularly useful for people with insomnia, bipolar disorder, delayed sleep phase disorder, or ADHD, though less beneficial for healthy sleepers.[39]

Aggressive advertisements may contribute to the incorrect public perception of the purported dangers of blue light. Even when research has shown no evidence to support the use of blue-blocking filters as a clinical treatment for digital eye strain, ophthalmic lens manufacturers continue to market them as lenses that reduce digital eye strain.[40]

The UK's General Optical Council has criticised Boots Opticians for their unsubstantiated claims regarding their line of blue-light filtering lenses; and the Advertising Standards Authority fined them £40,000. Boots Opticians sold the lenses for a £20 markup.[41] Trevor Warburton, speaking on behalf of the UK Association of Optometrists stated: "...current evidence does not support making claims that they prevent eye disease."[42].

In July 2022, a Gamer Advantage advert on Twitch channel BobDuckNWeave was banned by the Advertising Standards Authority for making claims that blue light glasses could improve sleep without substantiation.[43][44]

See also

References

  1. ↑ "Could blue light-blocking lenses decrease the risk of age-related macular degeneration?". Retina (Philadelphia, Pa.) 26 (1): 1–4. January 2006. doi:10.1097/00006982-200601000-00001. PMID 16395131. 
  2. ↑ "Do blue light filters confer protection against age-related macular degeneration?". Prog Retin Eye Res 23 (5): 523–31. September 2004. doi:10.1016/j.preteyeres.2004.05.001. PMID 15302349. 
  3. ↑ "Blue-light filtering spectacle lenses for visual performance, sleep, and macular health in adults.". Cochrane Database Syst Rev 2023 (8): CD013244. 2023. doi:10.1002/14651858.CD013244.pub2. PMID 37593770. PMC 10436683. https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD013244.pub2/full. 
  4. ↑ US. Department of energy. (2013). Solid-State Lighting Technology Fact Sheet (Optical Safety of LEDs). Available at: https://www.lightingglobal.org/wp-content/uploads/bsk-pdf-manager/82_opticalsafety_fact-sheet.pdf
  5. ↑ "Product family datasheet:Cree® XLamp® XM-L LEDs". Cree. p. 4. https://www.cree.com/led-components/media/documents/XLampXML-11E.pdf. 
  6. ↑ "Technical Data Sheet X42182(Z-power LEDs)". pp. 12–13. http://www.seoulsemicon.com/upload2/X42182(0).pdf. 
  7. ↑ "Colorimetry -- Part 1: CIE standard colorimetric observers". International Organization for Standardization. https://www.iso.org/standard/74164.html. 
  8. ↑ "Kay & Laby;tables of physical & chemical constants;General physics;SubSection: 2.5.3 Photometry". National Physical Laboratory; UK. http://www.kayelaby.npl.co.uk/general_physics/2_5/2_5_3.html. 
  9. ↑ Krigel, Arthur (2016). "Light-induced retinal damage using different light sources, protocols and rat strains reveals LED phototoxicity". Neuroscience (Centre de Recherches des Cordeliers. Université Paris Descartes, France.(Sorbonne University Faculty of Medicine, Physiology Department)) 339: 296–307. doi:10.1016/j.neuroscience.2016.10.015. PMID 27751961. https://hal.sorbonne-universite.fr/hal-01383394/file/Krigel_Light-induced.pdf. Retrieved December 9, 2018. 
  10. ↑ "Light-emitting-diode induced retinal damage and its wavelength dependency in vivo". International Journal of Ophthalmology, Vol. 10, No. 2. Feb 18, 2017. http://www.ijo.cn/en_publish/2017/2/20170203.pdf. 
  11. ↑ "LEDs & blue light | Anses - Agence nationale de sécurité Sanitaire de l'alimentation, de l'environnement et du travail". 13 August 2019. https://www.anses.fr/en/content/leds-blue-light. 
  12. ↑ Modenese, Alberto; Gobba, Fabriziomaria (September 6, 2018). "Macular degeneration and occupational risk factors: a systematic review". International Archives of Occupational and Environmental Health 92 (1): 1–11. doi:10.1007/s00420-018-1355-y. PMID 30191305. 
  13. ↑ "Position Statement on the Blue Light Hazard (April 23, 2019) | CIE" (in en). http://www.cie.co.at/publications/position-statement-blue-light-hazard-april-23-2019. 
  14. ↑ Tsankov, Plamen Ts. (2020). "Lighting Technologies". in Pavlovic, Tomislav. The Sun and Photovoltaic Technologies. Cham, Switzerland: Springer Nature Switzerland. p. 261. ISBN 978-3-030-22402-8. https://books.google.com/books?id=PEa5DwAAQBAJ. Retrieved May 26, 2022. 
  15. ↑ "The IEC addresses characterization of the blue light hazard (MAGAZINE)". 15 January 2014. https://www.ledsmagazine.com/smart-lighting-iot/smart-cities/article/16695043/the-iec-addresses-characterization-of-the-blue-light-hazard-magazine. 
  16. ↑ Enezi, Jazi al; Revell, Victoria; Brown, Timothy; Wynne, Jonathan; Schlangen, Luc; Lucas, Robert (August 2011). "A "Melanopic" Spectral Efficiency Function Predicts the Sensitivity of Melanopsin Photoreceptors to Polychromatic Lights". Journal of Biological Rhythms 26 (4): 314–323. doi:10.1177/0748730411409719. PMID 21775290. 
  17. ↑ "Blue Light Has A Dark Side". Harvard Health Letter. August 13, 2018. https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side. 
  18. ↑ "LEDs & blue light | Anses - Agence Nationale de sécurité Sanitaire de l'alimentation, de l'environnement et du travail". 13 August 2019. https://www.anses.fr/en/content/leds-blue-light. 
  19. ↑ "AMA adopts guidance to reduce harm from high intensity street lights" (in en). https://www.ama-assn.org/press-center/press-releases/ama-adopts-guidance-reduce-harm-high-intensity-street-lights. 
  20. ↑ Beaulé, C.; Robinson, B.; Lamont, E. W.; Amir, S. (2003). "Melanopsin in the circadian timing system". Journal of Molecular Neuroscience 21 (1): 73–89. doi:10.1385/JMN:21:1:73. PMID 14500998. https://www.ncbi.nlm.nih.gov/pubmed/14500998. 
  21. ↑ Rosenfield, Mark (2016). "Computer vision syndrome (aka digital eye strain)". Optometry in Practice 17 (1). 
  22. ↑ LaMotte, Sandee (2023-08-17). "Blue-light glasses don't help with eye strain, major study says" (in en). https://www.cnn.com/2023/08/17/health/blue-light-glasses-study-wellness/index.html. 
  23. ↑ "Light therapies for acne: abridged Cochrane systematic review including GRADE assessments". Br J Dermatol 178 (1): 61–75. January 2018. doi:10.1111/bjd.15495. PMID 28338214. 
  24. ↑ "Blue-Light Therapy for Acne Vulgaris: A Systematic Review and Meta-Analysis". Ann Fam Med 17 (6): 545–553. November 2019. doi:10.1370/afm.2445. PMID 31712293. 
  25. ↑ "How to use Night Shift on your Mac". March 13, 2019. https://support.apple.com/en-us/HT207513. 
  26. ↑ "Set your display for night time in Windows 10". March 13, 2019. https://support.microsoft.com/en-in/help/4027563/windows-10-set-your-display-for-night-time. 
  27. ↑ Bullough, John D.; Bierman, Andrew; Rea, Mark S. (3 April 2019). "Evaluating the blue-light hazard from solid state lighting". International Journal of Occupational Safety and Ergonomics 25 (2): 311–320. doi:10.1080/10803548.2017.1375172. PMID 28876164. 
  28. ↑ Mainster, Martin A.; Turner, Patricia L. (May 2010). "Blue-blocking IOLs Decrease Photoreception Without Providing Significant Photoprotection". Survey of Ophthalmology 55 (3): 272–283. doi:10.1016/j.survophthal.2009.07.006. PMID 19883931. 
  29. ↑ Vagge, Aldo; Ferro Desideri, Lorenzo; Del Noce, Chiara; Di Mola, Ilaria; Sindaco, Daniele; Traverso, Carlo E. (2021-03-18). "Blue light filtering ophthalmic lenses: A systematic review". Seminars in Ophthalmology (Informa UK Limited) 36 (7): 541–548. doi:10.1080/08820538.2021.1900283. ISSN 0882-0538. PMID 33734926. 
  30. ↑ Downie, L. E.; Busija, L.; Keller, P. R. (May 22, 2018). "Artificial, blue-light filtering lenses in the eye for protecting the macula (back of the eye) after cataract surgery". The Cochrane Database of Systematic Reviews (Cochrane) 2018 (5): CD011977. doi:10.1002/14651858.CD011977.pub2. PMID 29786830. PMC 6494477. https://www.cochrane.org/CD011977/EYES_artificial-blue-light-filtering-lenses-eye-protecting-macula-back-eye-after-cataract-surgery. 
  31. ↑ Nagai, H.; Hirano, Y.; Yasukawa, T.; Morita, H.; Nozaki, M.; Wolf-Schnurrbusch, U.; Wolf, S.; Ogura, Y. (September 2015). "Prevention of increased abnormal fundus autofluorescence with blue light-filtering intraocular lenses". Journal of Cataract and Refractive Surgery (Journal of Cataract & Refractive Surgery) 41 (9): 1855–9. doi:10.1016/j.jcrs.2015.01.017. PMID 26471051. 
  32. ↑ Bennett, Timothy J. (2017). "Equipment & Technique". Ophthalmic Photographers' Society. https://www.opsweb.org/page/FAequipment. 
  33. ↑ Bennett, Timothy J. (2017). "Fluorescein Fundamentals". Ophthalmic Photographers' Society. https://www.opsweb.org/page/FA. 
  34. ↑ Clark, B. a. J. (November 1969). "Color in Sunglass Lenses". Optometry and Vision Science 46 (11): 825–839. doi:10.1097/00006324-196911000-00004. ISSN 1538-9235. https://journals.lww.com/optvissci/Abstract/1969/11000/COLOR_IN_SUNGLASS_LENSES_.4.aspx. 
  35. ↑ Anderson, Kenneth V; Coyle, Frances P; O'Stben, W. Keith (1 May 1972). "Retinal degeneration produced by low-intensity colored light". Experimental Neurology 35 (2): 233–238. doi:10.1016/0014-4886(72)90149-5. PMID 5030851. 
  36. ↑ Ham, William T.; Mueller, Harold A.; Sliney, David H. (11 March 1976). "Retinal sensitivity to damage from short wavelength light". Nature 260 (5547): 153–155. doi:10.1038/260153a0. PMID 815821. Bibcode: 1976Natur.260..153H. 
  37. ↑ Hovis, Jeffery K.; Lovasik, John V.; Cullen, Anthony P.; Kothe, Angela C. (October 1989). "Physical Characteristics and Perceptual Effects of "Blue-Blocking" Lenses". Optometry and Vision Science 66 (10): 682–689. doi:10.1097/00006324-198910000-00004. ISSN 1538-9235. PMID 2587033. https://journals.lww.com/optvissci/Abstract/1989/10000/Physical_Characteristics_and_Perceptual_Effects_of.4.aspx. 
  38. ↑ Yousef, Tareq. "There's no evidence that blue‑light blocking glasses help with sleep" (in en). https://www.dal.ca/news/2020/09/08/there-s-no-evidence-that-blue-light-blocking-glasses-help-with-s.html. 
  39. ↑ Shechter, Ari; Quispe, Kristal A; Mizhquiri Barbecho, Jennifer S; Slater, Cody; Falzon, Louise (June 4, 2020). "Interventions to reduce short-wavelength ("blue") light exposure at night and their effects on sleep: A systematic review and meta-analysis". SLEEP Advances 1 (1): zpaa002. doi:10.1093/sleepadvances/zpaa002. PMID 37192881. PMC 10127364. https://academic.oup.com/sleepadvances/article/1/1/zpaa002/5851240?login=true. Retrieved May 25, 2022. 
  40. ↑ M, Rosenfield; RT, Li; NT, Kirsch (2020). "A double-blind test of blue-blocking filters on symptoms of digital eye strain". Work (Reading, Mass.) 65 (2): 343–348. doi:10.3233/WOR-203086. PMID 32007978. https://pubmed.ncbi.nlm.nih.gov/32007978/. 
  41. ↑ Woodley, Matthew (May 31, 2017). "Optical chain fined $69,000 for misleading ad". Insight. https://www.insightnews.com.au/Article3/810/Optical-chain-fined-69-000-for-misleading-ad. 
  42. ↑ Powell, Selina (May 26, 2017). "BOOTS OPTICIANS FINED £40,000 OVER MISLEADING BLUE LIGHT ADVERTISING". Optometry Today. https://www.aop.org.uk/ot/industry/high-street/2017/05/26/boots-opticians-fined-40000-over-misleading-blue-light-advertising. 
  43. ↑ "Gamer Advantage LLC". Advertising Standards Authority. https://www.asa.org.uk/rulings/gamer-advantage-llc-a22-1147415-gamer-advantage-llc.html. 
  44. ↑ "Gamer Advantage's Blue-Light Glasses" (in en). 2022. https://truthinadvertising.org/articles/gamer-advantages-blue-light-glasses/. 




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