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Author (up) Gringras, P.; Middleton, B.; Skene, D.J.; Revell, V.L. url  doi
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  Title Bigger, Brighter, Bluer-Better? Current Light-Emitting Devices – Adverse Sleep Properties and Preventative Strategies Type Journal Article
  Year 2015 Publication Frontiers in Public Health Abbreviated Journal Front Public Health  
  Volume 3 Issue Pages 233  
  Keywords Ligthing; apps; light; melatonin; sleep disorders; smartphone; tablets; chronobiology; photobiology  
  Abstract OBJECTIVE: In an effort to enhance the efficiency, brightness, and contrast of light-emitting (LE) devices during the day, displays often generate substantial short-wavelength (blue-enriched) light emissions that can adversely affect sleep. We set out to verify the extent of such short-wavelength emissions, produced by a tablet (iPad Air), e-reader (Kindle Paperwhite 1st generation), and smartphone (iPhone 5s) and to determine the impact of strategies designed to reduce these light emissions.

SETTING: University of Surrey dedicated chronobiology facility.

METHODS: First, the spectral power of all the LE devices was assessed when displaying identical text. Second, we compared the text output with that of “Angry Birds” – a popular top 100 “App Store” game. Finally, we measured the impact of two strategies that attempt to reduce the output of short-wavelength light emissions. The first strategy employed an inexpensive commercially available pair of orange-tinted “blue-blocking” glasses. The second strategy tested an app designed to be “sleep-aware” whose designers deliberately attempted to reduce short-wavelength light emissions.

RESULTS: All the LE devices shared very similar enhanced short-wavelength peaks when displaying text. This included the output from the backlit Kindle Paperwhite device. The spectra when comparing text to the Angry Birds game were also very similar, although the text emissions were higher intensity. Both the orange-tinted glasses and the “sleep-aware” app significantly reduced short-wavelength emissions.

CONCLUSION: The LE devices tested were all bright and characterized by short-wavelength enriched emissions. Since this type of light is likely to cause the most disruption to sleep as it most effectively suppresses melatonin and increases alertness, there needs to be the recognition that at night-time “brighter and bluer” is not synonymous with “better.” Ideally future software design could be better optimized when night-time use is anticipated, and hardware should allow an automatic “bedtime mode” that shifts blue and green light emissions to yellow and red as well as reduce backlight/light intensity.
 
  Address Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK; paul.gringras(at)gstt.nhs.uk  
  Corporate Author Thesis  
  Publisher Frontiers Media Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2296-2565 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:26528465; PMCID:PMC4602096 Approved no  
  Call Number IDA @ john @ Serial 1306  
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