Blocking Blue Light Exposure from Smartphone Screens Improves Sleep Quality

by | Sep 9, 2020 | 2018, Brain Health, Sleep

Written by Angeline A. De Leon, Staff Writer. Blocking the short-wavelength blue light on cell phone screens with an amber filter improved the sleep quality of study participants.

cell phoneA growing body of research supports the critical role of retinal light exposure on human sleep quality 1, with studies highlighting the sensitivity of the circadian system to the short-wavelength portion of the visible light spectrum (blue light) 2. Nighttime exposure to artificial light is now known to adversely impact melatonin production in the brain 3, suppressing its production and thereby increasing risk of sleep disorders 4. Given the ubiquity of blue light exposure in modern times, reports estimate that a large percentage of the global population experiences nighttime exposure to artificial light, with numbers only projected to increase 5. Although blue light demonstrates certain therapeutic qualities and has been employed in phototherapy 6 and as part of antibacterial treatment regimens (periodontal disease) 7, nighttime exposure to artificial light, like that emitted by smartphone screens, has also been implicated in the development of certain types of cancer, including breast and prostate cancer 8. The full health effects associated with blue light are still being explored; however, from a sleep research perspective, regulation of nighttime blue light exposure from smartphone displays appears to have clear benefits 9. One sleep study, for example, reported that use of a blue-light shield not only improved sleep efficacy and sleep latency, but was also associated with greater sleepiness during use of a self-luminous portable device 10. In 2018, a study 11 published in the Journal of Biomedical Physics and Engineering investigated the effects of using different types of smartphone filters on the sleep quality of young adults.

A total of 43 healthy university students (15 males, 28 females, mean age = 23.58 years) were enrolled in an observational study in which they were instructed to watch a documentary film on their mobile phones for 60 minutes in bed for 3 consecutive nights. Each night, students were assigned to use one of three screen filter settings on their phone, changing the effective output spectra of passing light to blue light, amber light (allowing minimal blue light to pass through), or no filter (selected in random order), while maintaining consistent screen brightness. After 1 hour, subjects completed a sleep time sheet to record their sleep delay time.

At the end of the study, a mean sleep delay time of 20.84 +/- 9.15 minutes was observed for the “no filter” night, while use of amber and blue light filters was linked to a mean sleep delay time of 15.26 +/- 1.04 and 26.33 +/- 1.59 minutes, respectively.

General findings support the relationship between nighttime exposure to blue light emitted by smartphone displays and diminished quality of sleep. In line with literature suggesting that blue light exposure may suppress the production of melatonin (3, 4), the longest sleep delay time in the current study was associated with the blue filter, while the shortest delay time was associated with amber. Findings suggest that blocking exposure to the short-wavelength component of light emitted from smartphone screens may help enhance sleep quality. Some of the limitations that pertain to the current study involve the short duration of the study period, the absence of direct measures of melatonin, and the measurement of only a single parameter of sleep quality (sleep delay time). Additional studies are warranted, ideally using a larger sample size and a randomized, controlled design.

Source: Mortazavi SAR, Parhoodeh S, Hosseini MA, et al. Blocking short-wavelength component of the visible light emitted by smartphones’ screens improves human sleep quality. J Biomed Phys Eng. 2018; 8(4): 375.

Posted September 9, 2020.

Angeline A. De Leon, MA, graduated from the University of Illinois at Urbana-Champaign in 2010, completing a bachelor’s degree in psychology, with a concentration in neuroscience. She received her master’s degree from The Ohio State University in 2013, where she studied clinical neuroscience within an integrative health program. Her specialized area of research involves the complementary use of neuroimaging and neuropsychology-based methodologies to examine how lifestyle factors, such as physical activity and meditation, can influence brain plasticity and enhance overall connectivity.

References:

  1. Ichikawa K. Changes in blood pressure and sleep duration in patients with blue light-blocking/yellow-tinted intraocular lens (CHUKYO study). Hypertension research : official journal of the Japanese Society of Hypertension. 2014;37(7):659-664.
  2. Figueiro MG, Plitnick BA, Lok A, et al. Tailored lighting intervention improves measures of sleep, depression, and agitation in persons with Alzheimer’s disease and related dementia living in long-term care facilities. Clin Interv Aging. 2014;9:1527-1537.
  3. Kozaki T, Kubokawa A, Taketomi R, Hatae K. Light-induced melatonin suppression at night after exposure to different wavelength composition of morning light. Neurosci Lett. 2016;616:1-4.
  4. Figueiro MG, Plitnick B, Rea MS. Pulsing blue light through closed eyelids: effects on acute melatonin suppression and phase shifting of dim light melatonin onset. Nature and science of sleep. 2014;6:149-156.
  5. Tosini G, Ferguson I, Tsubota K. Effects of blue light on the circadian system and eye physiology. Mol Vis. 2016;22:61-72.
  6. Ebbesen F, Vandborg PK, Madsen PH, Trydal T, Jakobsen LH, Vreman HJ. Effect of phototherapy with turquoise vs. blue LED light of equal irradiance in jaundiced neonates. Pediatr Res. 2016;79(2):308-312.
  7. Mahdi Z, Habiboallh G, Mahbobeh NN, Mina ZJ, Majid Z, Nooshin A. Lethal effect of blue light-activated hydrogen peroxide, curcumin and erythrosine as potential oral photosensitizers on the viability of Porphyromonas gingivalis and Fusobacterium nucleatum. Laser therapy. 2015;24(2):103-111.
  8. Smolensky MH, Sackett-Lundeen LL, Portaluppi F. Nocturnal light pollution and underexposure to daytime sunlight: Complementary mechanisms of circadian disruption and related diseases. Chronobiol Int. 2015;32(8):1029-1048.
  9. Oh JH, Yoo H, Park HK, Do YR. Analysis of circadian properties and healthy levels of blue light from smartphones at night. Scientific reports. 2015;5:11325.
  10. Ayaki M, Hattori A, Maruyama Y, et al. Protective effect of blue-light shield eyewear for adults against light pollution from self-luminous devices used at night. Chronobiol Int. 2016;33(1):134-139.
  11. Mortazavi SAR, Parhoodeh S, Hosseini MA, et al. Blocking Short-Wavelength Component of the Visible Light Emitted by Smartphones’ Screens Improves Human Sleep Quality. Journal of biomedical physics & engineering. 2018;8(4):375-380.