scholarly journals Preliminary Results: The Impact of Smartphone Use and Short-Wavelength Light during the Evening on Circadian Rhythm, Sleep and Alertness

2021 ◽  
Vol 3 (1) ◽  
pp. 66-86
Author(s):  
Christopher Höhn ◽  
Sarah R. Schmid ◽  
Christina P. Plamberger ◽  
Kathrin Bothe ◽  
Monika Angerer ◽  
...  
Keyword(s):  
Circadian Rhythm ◽  
Blue Light ◽  
Short Wavelength ◽  
Light Filter ◽  
Negative Effects ◽  
Sleep Physiology ◽  
Short Wavelength Light ◽  
Blue Light Filter ◽  
The Impact ◽  
Wavelength Light

Smartphone usage strongly increased in the last decade, especially before bedtime. There is growing evidence that short-wavelength light affects hormonal secretion, thermoregulation, sleep and alertness. Whether blue light filters can attenuate these negative effects is still not clear. Therefore, here, we present preliminary data of 14 male participants (21.93 ± 2.17 years), who spent three nights in the sleep laboratory, reading 90 min either on a smartphone (1) with or (2) without a blue light filter, or (3) on printed material before bedtime. Subjective sleepiness was decreased during reading on a smartphone, but no effects were present on evening objective alertness in a GO/NOGO task. Cortisol was elevated in the morning after reading on the smartphone without a filter, which resulted in a reduced cortisol awakening response. Evening melatonin and nightly vasodilation (i.e., distal-proximal skin temperature gradient) were increased after reading on printed material. Early slow wave sleep/activity and objective alertness in the morning were only reduced after reading without a filter. These results indicate that short-wavelength light affects not only circadian rhythm and evening sleepiness but causes further effects on sleep physiology and alertness in the morning. Using a blue light filter in the evening partially reduces these negative effects.

scholarly journals Short-Wavelength Light Enhances Cortisol Awakening Response in Sleep-Restricted Adolescents

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mariana G. Figueiro ◽  
Mark S. Rea
Keyword(s):  
Adrenal Gland ◽  
Short Wavelength ◽  
Light Exposure ◽  
Secondary Analysis ◽  
Cortisol Awakening Response ◽  
Dim Light ◽  
Short Wavelength Light ◽  
The Impact ◽  
Rising Time ◽  
Wavelength Light

Levels of cortisol, a hormone produced by the adrenal gland, follow a daily, 24-hour rhythm with concentrations reaching a minimum in the evening and a peak near rising time. In addition, cortisol levels exhibit a sharp peak in concentration within the first hour after waking; this is known as the cortisol awakening response (CAR). The present study is a secondary analysis of a larger study investigating the impact of short-wavelength(λmax≈470 nm)light on CAR in adolescents who were sleep restricted. The study ran over the course of three overnight sessions, at least one week apart. The experimental sessions differed in terms of the light exposure scenarios experienced during the evening prior to sleeping in the laboratory and during the morning after waking from a 4.5-hour sleep opportunity. Eighteen adolescents aged 12–17 years were exposed to dim light or to 40 lux (0.401 W/m2) of 470-nm peaking light for 80 minutes after awakening. Saliva samples were collected every 20 minutes to assess CAR. Exposure to short-wavelength light in the morning significantly enhanced CAR compared to dim light. Morning exposure to short-wavelength light may be a simple, yet practical way to better prepare adolescents for an active day.

Wavelength-dependent effects of evening light exposure on sleep architecture and sleep EEG power density in men

2006 ◽  
Vol 290 (5) ◽  
pp. R1421-R1428 ◽  
Author(s):  
Mirjam Münch ◽  
Szymon Kobialka ◽  
Roland Steiner ◽  
Peter Oelhafen ◽  
Anna Wirz-Justice ◽  
...  
Keyword(s):  
Blue Light ◽  
Rem Sleep ◽  
Short Wavelength ◽  
Sleep Eeg ◽  
Sleep Architecture ◽  
Circadian Phase ◽  
Eeg Power ◽  
The Impact ◽  
Wavelength Light ◽  
Sleep Cycles

Light strongly influences the circadian timing system in humans via non-image-forming photoreceptors in the retinal ganglion cells. Their spectral sensitivity is highest in the short-wavelength range of the visible light spectrum as demonstrated by melatonin suppression, circadian phase shifting, acute physiological responses, and subjective alertness. We tested the impact of short wavelength light (460 nm) on sleep EEG power spectra and sleep architecture. We hypothesized that its acute action on sleep is similar in magnitude to reported effects for polychromatic light at higher intensities and stronger than longer wavelength light (550 nm). The sleep EEGs of eight young men were analyzed after 2-h evening exposure to blue (460 nm) and green (550 nm) light of equal photon densities (2.8 × 1013 photons·cm−2·s−1) and to dark (0 lux) under constant posture conditions. The time course of EEG slow-wave activity (SWA; 0.75–4.5 Hz) across sleep cycles after blue light at 460 nm was changed such that SWA was slightly reduced in the first and significantly increased during the third sleep cycle in parietal and occipital brain regions. Moreover, blue light significantly shortened rapid eye movement (REM) sleep duration during these two sleep cycles. Thus the light effects on the dynamics of SWA and REM sleep durations were blue shifted relative to the three-cone visual photopic system probably mediated by the circadian, non-image-forming visual system. Our results can be interpreted in terms of an induction of a circadian phase delay and/or repercussions of a stronger alerting effect after blue light, persisting into the sleep episode.

Yellow Intraocular Lenses – To Block or Not to Block

2009 ◽  
Vol 03 (02) ◽  
pp. 77 ◽  
Author(s):  
Elfriede Wenzl ◽  
Matthias G Wirtitsch ◽  
Navid Ardjomand ◽  
◽  
◽  
...  
Keyword(s):  
Cataract Surgery ◽  
Short Wavelength ◽  
Chromatic Aberration ◽  
Positive Influence ◽  
Light Filter ◽  
Intraocular Lenses ◽  
Age Related Macular Degeneration ◽  
Age Related ◽  
Short Wavelength Light ◽  
Wavelength Light

Yellow filters for the eye have been of interest to ophthalmologists and optometrists for the last 30 years. Certain fish species can change the colour of the cornea in response to the level of illumination and regulate the amount of short-wavelength light reaching the retina. A positive influence of yellow eye filters on reduction of chromatic aberration has been found in a fish eye model. Blue-light-filter (yellow) intraocular lenses (IOLs) were introduced for cataract surgery almost 20 years ago. The main advantage of yellow IOLs is thought to be the reduction of chromatic aberration under photopic conditions and protection of the retina from phototoxic short-wavelength light, especially in eyes at risk of age-related macular degeneration (AMD). This article highlights the importance of yellow IOLs for cataract surgery in terms of quality of vision and AMD protection.

257 How Much Blue Do Blue-Blockers Block if Blue-Blockers Do Block Blue?

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A103-A103
Author(s):  
Brooke Mason ◽  
Andrew Tubbs ◽  
William Killgore ◽  
Fabian-Xosé Fernandez ◽  
Michael Grandner
Keyword(s):  
Light Source ◽  
Blue Light ◽  
Short Wavelength ◽  
Light Exposure ◽  
Visible Spectrum ◽  
Group Differences ◽  
Melatonin Secretion ◽  
Short Wavelength Light ◽  
Wavelength Light ◽  
One Way Anova

Abstract Introduction Short-wavelength light (440-530nm) can suppress endogenous melatonin secretion from the pineal gland. This has been observed in realworld settings when people use electronic media at night that emits light from this part of the visible spectrum. Blue-blocking glasses are a possible intervention to reduce blue light exposure. The present study evaluated the ability of commercially available blue-blockers to block blue light emitted by LEDs. Methods A calibrated spectroradiometer (Ocean Insight), cosine corrector, optic fiber, and software package were used to measure the absolute irradiance (uW/cm^2/nm) generated from a blue light source (Phillips Go Lite Blu) in an otherwise completely dark room. Thirty-one different commercially-available blue-blockers were individually placed between the cosine corrector and the light source at a standardized distance, and then intensity was measured and analyzed. Lenses were evaluated with regards to the amount of blue light they suppressed both individually and grouped by lens tint: red-tinted lenses (RTL), orange-tinted lenses (OTL), orange-tinted lenses with blue reflectivity (OBL), brown-tinted lenses (BTL), yellow-tinted lenses (YTL), and clear lenses with blue reflectivity (RBL). Results RTL blocked 100% of the short-wavelength light, while OTL and OBL blocked 99%, BTL blocked 66%, YTL blocked 38%, and RBL blocked 11% of it. This represented a statistically significant between-group difference (one-way ANOVA, < 0.0001). Within groups, there was variability in performance among individual lenses, though this variability was small compared to the between-group differences. Conclusion The RTL, OTL, and OBL block light best capable of suppressing melatonin secretion at night (440-530 nm); with slightly less efficacy, BTL and YTL also restricted much of the light exposure. Lastly, RBL were not effective at curtailing short-wavelength light. Those looking to optimize blue-blocking capabilities should use RTL, OTL, and OBL, rather than other lens types. Support (if any):

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