scholarly journals Electrochromic selective filtering of chronodisruptive visible wavelengths

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241900
Author(s):  
Maria Angeles Bonmati-Carrion ◽  
Javier Padilla ◽  
Raquel Arguelles-Prieto ◽  
Anna M. Österholm ◽  
John R. Reynolds ◽  
...  
Keyword(s):  
Blue Light ◽  
Ganglion Cells ◽  
Light Exposure ◽  
Control Sample ◽  
Color Naming ◽  
Internal Clock ◽  
Light Sources ◽  
Melatonin Suppression ◽  
Pupil Constriction ◽  
Visible Wavelengths

We present evidence of pupil response modification, as well as differential theoretical melatonin suppression through selective and dynamic electrochromic filtering of visible light in the 400–500 nm range to minimize chronodisruptive nocturnal blue light exposure. A lower activation of intrinsically photosensitive retinal ganglion cells (ipRGCs), the first step for light to reach a human’s internal clock, is related to melatonin secretion therefore avoiding detrimental effects of excessive blue light exposure. Pupillary Light Reflex and Color Naming were experimentally assessed under light filtered by two different coloration states (transmissive and absorptive) of these novel dynamic filters, plus an uncoated test device, in 16 volunteers. Also, different commercial light sources at illuminances ranging from 1 to 1000 lux were differentially filtered and compared in terms of theoretical melatonin suppression. Representative parameters of the pupil responses reflected lower pupil constriction when the electrochromic filters (ECFs) were switched on (absorptive state, blue light is absorbed by the filter) compared to uncoated filters (control sample), but failed to do so under transmissive state (blue light passes through the filter) indicating less activation of ipRGCs under absorptive state (although no significant differences between states was found). Out of eight colors tested, just one showed significant differences in naming between both filter states. Thus, the ECF would have some protecting effect on ipRGC activation with very limited changes in color perception. While there are some limitations of the theoretical model used, the absorptive state yielded significantly lower theoretical melatonin suppression in all those light sources containing blue wavelengths across the illuminance range tested. This would open the way for further research on biological applications of electrochromic devices.

scholarly journals Visible blue light inhibits infection and replication of SARS-CoV-2 at doses that are well-tolerated by human respiratory tissue

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nathan Stasko ◽  
Jacob F. Kocher ◽  
Abigail Annas ◽  
Ibrahim Henson ◽  
Theresa S. Seitz ◽  
...  
Keyword(s):  
Visible Light ◽  
Blue Light ◽  
Light Exposure ◽  
Light Emitting Diode ◽  
Spectral Band ◽  
Dependent Manner ◽  
Light Emitting ◽  
Biological Surfaces ◽  
Visible Wavelengths ◽  
High Doses

AbstractThe delivery of safe, visible wavelengths of light can be an effective, pathogen-agnostic, countermeasure that would expand the current portfolio of SARS-CoV-2 intervention strategies beyond the conventional approaches of vaccine, antibody, and antiviral therapeutics. Employing custom biological light units, that incorporate optically engineered light-emitting diode (LED) arrays, we harnessed monochromatic wavelengths of light for uniform delivery across biological surfaces. We demonstrated that primary 3D human tracheal/bronchial-derived epithelial tissues tolerated high doses of a narrow spectral band of visible light centered at a peak wavelength of 425 nm. We extended these studies to Vero E6 cells to understand how light may influence the viability of a mammalian cell line conventionally used for assaying SARS-CoV-2. The exposure of single-cell monolayers of Vero E6 cells to similar doses of 425 nm blue light resulted in viabilities that were dependent on dose and cell density. Doses of 425 nm blue light that are well-tolerated by Vero E6 cells also inhibited infection and replication of cell-associated SARS-CoV-2 by > 99% 24 h post-infection after a single five-minute light exposure. Moreover, the 425 nm blue light inactivated cell-free betacoronaviruses including SARS-CoV-1, MERS-CoV, and SARS-CoV-2 up to 99.99% in a dose-dependent manner. Importantly, clinically applicable doses of 425 nm blue light dramatically inhibited SARS-CoV-2 infection and replication in primary human 3D tracheal/bronchial tissue. Safe doses of visible light should be considered part of the strategic portfolio for the development of SARS-CoV-2 therapeutic countermeasures to mitigate coronavirus disease 2019 (COVID-19).

scholarly journals Artificial light sources as light pollutant of humans melatonin suppression

2019 ◽  
Vol 11 (3) ◽  
pp. 78 ◽  
Author(s):  
Piotr Jakubowski
Keyword(s):  
Blue Light ◽  
Power Distribution ◽  
Optical Radiation ◽  
Spectral Power ◽  
International Workshop ◽  
Action Spectrum ◽  
Legal Aspects ◽  
Light Sources ◽  
Research Technology ◽  
Melatonin Suppression

Blue light emitted by LEDs might influence on natural biological rhythm of human being, what can be considered as environment pollution. In this paper the effect of the latest commercially available LEDs on melatonin suppression index (MSI) was analyzed. Research was done based on spectral power distribution of given LED (SPD) and melatonin suppression function in reference to melatonin suppression under daylight (illuminant D65). Results of calculations shows strong correlation between CCT and MSI, however MSI factor might vary for different LEDs with same CCT. Full Text: PDF ReferencesC. C. Sun, et al., Packaging efficiency in phosphor-converted white LEDs and its impact to the limit of luminous efficacy, Journal of Solid State Lighting, 1:19, (2014). CrossRef M. S. Rea, M. G. Figueiro, J. D. Bullough, "Circadian photobiology: An emerging framework for lighting practice and research", Light Research Technology Vol. 34(3), (2002). CrossRef I. Fryc, P. Jakubowski, K. Kołacz, Analysis of optical radiation parameters of compact discharge HID lamps and LED COB modules used for illuminating shop windows, Przeglad Elektrotechniczny, R. 93, No. 11, (2017). CrossRef G. C. Brainard, J. P. Hanifin, J.M. Greeson, B. Byrne, E. Gerner, D. D. Rollang, "Action spectrum for melatonin regulation in humans: evidence for a novel circadian photoreceptor", Journal of Neuroscience vol. 21, (2001). CrossRef K. Thapan, J. Arendt, D. J. Skene, "An action spectrum for melatonin supression: evidence for a novel non-rod, non-cone photoreceptor system in humans," Journal of Physiology vol. 535, (2001). CrossRef I. Fryc, J. Fryc, P. Jakubowski, K. A. Wąsowski, Technical, medical and legal aspects of domestic light sources photobiological safety, Przeglad Elektrotechniczny, R. 93, No. 3, (2017). CrossRef J. Enzi et. al, A "Melanopic" Spectral Efficiency Function Predicts the Sensitivity of Melanopsin Photoreceptors to Polychromatic Lights Journal of biological rhytms, Vol. 26 No. 4, (2011). CrossRef M. Aube, J. Roby J, M. Kocifaj, Evaluating Potential Spectral Impacts of Various Artificial Lights on Melatonin Suppression, Photosynthesis, and Star Visibility. PLOS ONE, Vol. 8, (2013). CrossRef P. Jakubowski, I. Fryc, Metrological requirements for measurements of circadian radiation, Optica Applicata, Vol. 48 Issue 4, (2018). CrossRef P. Jakubowski, I. Fryc, Measurement methods of optical radiation in circadian active range, Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej, nr 54 (2017). DirectLink P. Jakubowski, Comparative analysis of light parameters of LEDs and OLEDs in context of blue light emission, Polish Journal for Sustainable Development 21 (2), (2017). CrossRef CIE TN003:2015, "Report on the First International Workshop on Circadian and neurophysiological Photometry", (2015). DirectLink

scholarly journals The effect of blue-blocking lenses on photostress recovery times for low and high contrast chromatic and achromatic stimuli

2019 ◽  
Author(s):  
Hind Saeed Alzahrani ◽  
Sieu K. Khuu ◽  
Adiba Ali ◽  
Maitreyee Roy
Keyword(s):  
Light Exposure ◽  
Bright Light ◽  
Light Sources ◽  
High Contrast ◽  
Night Time ◽  
Low Light ◽  
Low Contrast ◽  
Light Levels ◽  
Recovery Times ◽  
Visible Wavelengths

AbstractThe selective reduction in visible wavelengths transmitted through commercially available blue-blocking lenses (BBLs) is known to influence the appearance and contrast detection of objects, particularly at low light levels which may impact the human retinal receptor response time to dynamic light changes during phostress events. In the present study, we assessed whether BBLs selectively affect photostress recovery times (PSRTs) in 12 participants for chromatic and achromatic stimuli presented under low and high contrast luminance conditions. Four types of commercially available BBLs were evaluated, and their effects on PSRTs were investigated. Our results showed that PSRTs required to detect high contrast chromatic and achromatic stimuli were unaffected by BBLs when compared to a clear control lens. However, PSRTs were significantly affected by BBLs and were longer when chromatic and achromatic stimuli were of low contrast. In addition, BBLs had the greatest impact on the PSRTs of blue coloured targets, and this was dependent on the spectral transmittance profile. These results indicate that wearing BBLs under low contrast conditions can have serious implications for visual behavior, particularly under low-light levels and in situations in which the observer is directly exposed to bright light sources. For example, during night time driving, the driver might be briefly exposed to bright lights by glancing at the headlights of a passing car. This increases the time required for vision to be restored after bright light exposure, resulting in delayed object detection, and therefore stoppage and reaction times, which might pose a safety risk for a driver.

scholarly journals Correlated color temperature and light intensity: Complementary features in non-visual light field

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254171
Author(s):  
Raquel Arguelles-Prieto ◽  
Juan Antonio Madrid ◽  
Maria Angeles Rol ◽  
Maria Angeles Bonmati-Carrion
Keyword(s):  
Ganglion Cells ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Color Temperature ◽  
Theoretical Modelling ◽  
Light Sources ◽  
Retinal Ganglion ◽  
Melatonin Suppression ◽  
Retinal Photoreceptors ◽  
Light Effects

An appropriate exposure to the light-dark cycle, with high irradiances during the day and darkness during the night is essential to keep our physiology on time. However, considering the increasing exposure to artificial light at night and its potential harmful effects on health (i.e. chronodisruption and associated health conditions), it is essential to understand the non-visual effects of light in humans. Melatonin suppression is considered the gold standard for nocturnal light effects, and the activation of intrinsically photosensitive retinal ganglion cells (ipRGCs) through the assessment of pupillary light reflex (PLR) has been recently gaining attention. Also, some theoretical models for melatonin suppression and retinal photoreceptors activation have been proposed. Our aim in this study was to determine the influence of correlated color temperature (CCT) on melatonin suppression and PLR, considering two commercial light sources, as well as to explore the possible correlation between both processes. Also, the contribution of irradiance (associated to CCT) was explored through mathematical modelling on a wider range of light sources. For that, melatonin suppression and PLR were experimentally assessed on 16 healthy and young volunteers under two light conditions (warmer, CCT 3000 K; and cooler, CCT 5700 K, at ~5·1018 photons/cm2/sec). Our experimental results yielded greater post-stimulus constriction under the cooler (5700 K, 13.3 ± 1.9%) than under the warmer light (3000 K, 8.7 ± 1.2%) (p < 0.01), although no significant differences were found between both conditions in terms of melatonin suppression. Interestingly, we failed to demonstrate correlation between PLR and melatonin suppression. Although methodological limitations cannot be discarded, this could be due to the existence of different subpopulations of Type 1 ipRGCs differentially contributing to PLR and melatonin suppression, which opens the way for further research on ipRGCs projection in humans. The application of theoretical modelling suggested that CCT should not be considered separately from irradiance when designing nocturnal/diurnal illumination systems. Further experimental studies on wider ranges of CCTs and light intensities are needed to confirm these conclusions.

Nighttime Blue Light Exposure and Breast Cancer

2021 ◽  
pp. 30-33
Author(s):  
David Jaynes ◽  
Paul Switzer
Keyword(s):  
Breast Cancer ◽  
Risk Factor ◽  
Blue Light ◽  
Shift Work ◽  
Light Exposure ◽  
Night Shift ◽  
Background Information ◽  
Common Disease ◽  
Essential Information ◽  
Night Shift Work

The purpose of this article is to provide background information and the current understanding of a less familiar cause of female breast cancer; exposure to ultraviolet light at night. Breast cancer is a common disease that causes significant morbidity and mortality in women. There are several risk factors for breast cancer, most of which are genetic and environmental in nature. An often-overlooked risk factor is exposure to blue light during night shift work, which decreases melatonin production. One of the many cancer-preventing properties of melatonin is to limit estrogen production. Increased lifetime exposure to estrogen is a well-known cause of breast cancer. Awareness of nighttime blue light exposure as a breast cancer risk factor by women doing night shift work and those exposed to nighttime light via smartphones and laptops, is essential information to know so that protective measures can be taken.

Effects of pre-bedtime blue-light exposure on ratio of deep sleep in healthy young men

2021 ◽  
Author(s):  
Masao Ishizawa ◽  
Takuya Uchiumi ◽  
Miki Takahata ◽  
Michiyasu Yamaki ◽  
Toshiaki Sato
Keyword(s):  
Blue Light ◽  
Light Exposure ◽  
Young Men ◽  
Deep Sleep

scholarly journals Fundamentals of circadian entrainment by light

2021 ◽  
Vol 53 (5) ◽  
pp. 377-393
Author(s):  
RG Foster
Keyword(s):  
Ganglion Cells ◽  
Light Exposure ◽  
Bright Light ◽  
Evidence Based ◽  
Retinal Ganglion ◽  
Rods And Cones ◽  
Long Duration ◽  
Lighting Systems ◽  
Short Wavelength Light ◽  
Wavelength Light

Light at dawn and dusk is the key signal for the entrainment of the circadian clock. Light at dusk delays the clock. Light at dawn advances the clock. The threshold for human entrainment requires relatively bright light for a long duration, but the precise irradiance/duration relationships for photoentrainment have yet to be fully defined. Photoentrainment is achieved by a network of photosensitive retinal ganglion cells (pRGCs) which utilise the short-wavelength light-sensitive photopigment, melanopsin. Although rods and cones are not required, they do play a role in photoentrainment, by projecting to and modulating the endogenous photosensitivity of the pRGCs, but in a manner that remains poorly understood. It is also important to emphasise that the age and prior light exposure of an individual will modify the efficacy of entrainment stimuli. Because of the complexity of photoreceptor interactions, attempts to develop evidence-based human centric lighting are not straightforward. We need to study how humans respond to dynamic light exposure in the ‘real world’ where light intensity, duration, spectral quality and the time of exposure vary greatly. Defining these parameters will allow the development of electric lighting systems that will enhance human circadian entrainment.

scholarly journals Predicting conversion to dementia of the Alzheimer’s type in a healthy control sample: The power of errors in stroop color naming.

2010 ◽  
Vol 25 (1) ◽  
pp. 208-218 ◽  
Author(s):  
David A. Balota ◽  
Chi-Shing Tse ◽  
Keith A. Hutchison ◽  
Daniel H. Spieler ◽  
Janet M. Duchek ◽  
...  
Keyword(s):  
Control Sample ◽  
Color Naming ◽  
Healthy Control Sample ◽  
Healthy Control

Blue light-induced retinal damage: a brief review and a proposal for examining the hypothetical causal link between person digital device use and retinal injury

2021 ◽  
Vol 1 (3) ◽  
pp. 129-134
Author(s):  
Michael R. Kozlowski
Keyword(s):  
Blue Light ◽  
Additional Data ◽  
Light Exposure ◽  
High Energy ◽  
Causal Link ◽  
Retinal Damage ◽  
Digital Devices ◽  
Retinal Injury ◽  
Device Use ◽  
Harmful Effects

Background: There is growing concern that the increased use of personal digital devices, which emit a high proportion of their light in the blue wavelengths, may have harmful effects on the retina. Extensive historical as well as current research demonstrates that exposure to high energy visible light (blue light) can damage the retina under certain circumstances. There are, however, no studies that directly address whether blue light at the intensities emitted by digital devices can potentially cause such harm. The present review aimed to examine whether blue light exposure from computers, tablets, and cell phones can, when used habitually over a prolonged period of time, be harmful to the retinal. Methods: A search of the literature on blue light-induced retinal damage was performed using a number of scientific search engines, including BioOne Complete™, Google Scholar™, Paperity™, PubMed™, and ScienceOpen™. Studies most significant for addressing the question of possible harmful effects of blue light emitted by personal digital devices were selected from this search and reviewed. Results: The data from the selected studies were summarized and their limitations in addressing the question of whether the blue light from personal digital devices is capable of producing retinal damage were addressed. Based on these limitations, a practical experimental protocol for collecting the additional data needed was proposed. Data from pilot experiments are presented that indicate the practicality of this approach. Conclusions: The currently available data on the effects of blue light on the retina are not sufficient to refute the hypothesis that the use of personal digital devices could, over a lifetime, produce retinal damage. Additional studies, such as those proposed in this article, are needed to resolve this issue.

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