Blue Light Hazard Research Articles

Realization of a Healthy Spectrum With High Color Rendering Index and Low Blue Light Hazard Based on Longitudinal Regulation of Luminous Intensity Ratio

Realization of a Healthy Spectrum With High Color Rendering Index and Low Blue Light Hazard Based on Longitudinal Regulation of Luminous Intensity Ratio

A highly transparent cellulose film for shielding ultraviolet and high-energy visible blue light.

The ultraviolet (UV) and high-energy visible blue (HEVB) light can cause damage to the eyes and skin. In this study, a cellulose composite film with UV and HEVB light shielding properties was prepared through the incorporation of a shielding agent into a carboxymethyl cellulose (CMC) solution. The shielding agent was synthesized through a Schiff base reaction between vanillin (VA) and 3-aminopropyltriethoxysilane (APS). The composite films exhibited excellent shielding performance against UV and HEVB light and maintained high visible light transmittance. Additionally, the films achieved shielding ratios of 100% for UV (200 to 400nm) and 93% for HEVB (400 to 450nm), respectively. Even under prolonged UV irradiation, the composite films maintained excellent shielding stability. The composite films exhibited higher performance in blocking UV and HEVB light than commercial shielding films. Moreover, the composite films achieved 100% antibacterial efficiency against both Staphylococcus aureus and Escherichia coli, even with minimal amounts of the shielding agent. Furthermore, the films exhibited significant improvements in thermal stability, oxidation resistance, and mechanical properties. The multifunctional UV and HEVB shielding films have broad potential applications in food packaging, anti-UV/HEVB radiation display screens, and mobile phone screens.

High-Performance Quantum Dot Near-Infrared Upconversion Devices Based on the Hole-Only Injection Mechanidsm.

Colloidal quantum dot (CQD) near-infrared (NIR) upconversion devices (UCDs) can directly convert low-energy NIR light into higher energy visible light without the need for additional integrated circuits, which is advantageous for NIR sensing and imaging. However, the state-of-the-art CQD NIR upconverters still face challenges, including high turn-on voltage (Von), low photon-to-photon (p-p) upconversion efficiency, and low current on/off ratio, primarily due to inherent limitations in the device structure and operating mechanisms. In this work, we developed a CQD NIR UCD based on a hole-only injection mechanism. Our device effectively suppresses electron injection from the cathode without hindering hole injection from the anode. As a result, the dark current of the device is reduced to a low level, which is favorable for the balance of photogenerated carriers and injected charges. Furthermore, we employed a liquid-phase ligand-exchange process to treat the PbS CQD photosensitive layer (PSL), which enhances the uniformity and charge transport capability of PSL, further optimizing the utilization of photogenerated carriers. We achieved a record high current on/off ratio exceeding 3.5 × 105 for the CQD NIR UCD. Additionally, the device exhibits a high p-p upconversion efficiency of 12.8% and a low Von of 1.8 V.

Multi-primary-color light-emitting diode display schemes in terms of color gamut, blue light hazard, and circadian rhythm

Multi-primary-color light-emitting diode display schemes in terms of color gamut, blue light hazard, and circadian rhythm

Enhanced upconversion and photoconductive nanocomposites of lanthanide-doped nanoparticles functionalized with low-vibrational-energy inorganic ligands.

Upconverting nanoparticles (UCNPs) convert near-infrared (IR) light into higher-energy visible light, allowing them to be used in applications such as biological imaging, nano-thermometry, and photodetection. It is well known that the upconversion luminescent efficiency of UCNPs can be enhanced by using a host material with low phonon energies, but the use of low-vibrational-energy inorganic ligands and non-epitaxial shells has been relatively underexplored. Here, we investigate the functionalization of lanthanide-doped NaYF4 UCNPs with low-vibrational-energy Sn2S64- ligands. Raman spectroscopy and elemental mapping are employed to confirm the binding of Sn2S64- ligands to UCNPs. This binding enhances upconversion efficiencies up to a factor of 16, consistent with an increase in the luminescent lifetimes of the lanthanide ions. Annealing Sn2S64--capped UCNPs results in the formation of a nanocomposite comprised of UCNPs embedded within an interconnected matrix of SnS2, enabling each UCNP to be electrically accessible through the semiconducting SnS2 matrix. This facilitates the integration of UCNPs into electronic devices, which we demonstrate through the fabrication of a UCNP-SnS2 photodetector that detects UV and near-IR light. Our findings show the promise of using inorganic capping agents to enhance the properties of UCNPs while facilitating their integration into optoelectronic devices.

Managing Blue Light Exposure: Impacts on Sleep Quality and Circadian Health

Introduction: Blue light, a high-energy visible light emitted from natural and artificial sources, plays a crucial role in regulating circadian rhythms and sleep quality. While essential for maintaining alertness and synchronizing the biological clock, excessive exposure, especially during evening hours, disrupts melatonin production, adversely impacting sleep and overall health. Purpose of Work: This paper investigates the effects of blue light exposure on circadian rhythms and sleep quality, aiming to evaluate its biological mechanisms and health implications. Additionally, it explores evidence-based preventive measures to mitigate its negative impacts. State of Knowledge: Research reveals that prolonged blue light exposure delays sleep onset, shortens sleep duration, and impairs sleep efficiency by suppressing melatonin secretion. Disrupted circadian rhythms are linked to mood disorders, cognitive decline, and metabolic imbalances. Preventive strategies, including blue light-blocking glasses, screen filters, optimized lighting environments, and adherence to healthy screen-time habits, demonstrate effectiveness but require further validation in diverse populations. Material and methods: This study employed a systematic literature review approach, comprising a comprehensive search across scientific databases such as PubMed and Google Scholar, followed by a screening process to identify relevant studies for further investigation. Summary: Blue light exposure significantly influences circadian rhythms and sleep quality, with implications for mental and physical health. Preventive measures, when adopted consistently, offer promising solutions to mitigate adverse effects. Continued research is necessary to refine these strategies and ensure widespread applicability in an increasingly digital world.

In Vitro Testing of Protective Eye Wear in Blocking Blue Light from Dental Light Curing Unit

Aim: To evaluate the ef?cacy of wearing protective eyewear in preventing harmful Dental light-curing units (LCUs). Background: Dental light-curing units generate blue light, capable of inducing soft-tissue burns and ocular harm like retinal damage. The intensity of blue light emitted by dental Light Curing Units is substantially higher, thereby potentially constituting a significant "blue light hazard." Material and Methods: To study the effect of protective glasses, reverse methodology was followed as the effect of blue light on the eye is difficult to measure; Circular composite disc samples were grouped into two, one of which was polymerized directly while the other had protective glass in between, Fourier transform infrared spectroscopy (FTIR) analysis was done and the degree of conversion was calculated. Results: Data obtained were analysed using One Way ANOVA. The mean values for "Degree of Conversion" in Group I (Without Protective Glass) is 1.334 +512 and for Group II (with protective glass) is -2.623 + 1.544 .One Way ANOVA revealed statistically significant difference between Group I and Group II (p=0.000) Conclusion: Within the limitations of this in vitro study, it can be concluded that the protective glasses are successful in filtering the harmful blue light emitted by LCU and should be used in day-to-day practice to improve the amount of light they deliver to the restoration from the LCU and prevent any harm to the ocular tissues. Clinical implications: Blue light filtering glasses in a dental operatory provide optimum protection, and the operator can safely watch and improve the amount of light delivered to the restoration from the LCU.

Stabilizing Dye-Sensitized Upconversion Hybrids by Cyclooctatetraene.

Lanthanide-doped upconversion nanoparticles (UCNPs) can convert low-energy near-infrared (NIR) light into high-energy visible light, making them valuable for broad applications. UCNPs often suffer from poor light-harvesting capabilities, which can be significantly improved by incorporating organic dye antennas. However, the dye-sensitized upconversion systems are prone to severe photobleaching in an ambient atmosphere. Here, we present a synergistic approach to mitigate photobleaching by introducing triplet state quencher cyclooctatetraene (COT). COT effectively suppresses the generation of singlet oxygen by quenching the triplet states of the dye and consumes the existing singlet oxygen through oxidant reactions. The inclusion of COT extends the half-life of IR806 by 4.7-times by preventing the oxidation of its poly(methylene) chains. Without significantly affecting emission intensity and dynamics, COT effectively stabilized dye-UCNPs, demonstrating a notable 3.9-fold increase in half-life under continuous laser irradiation. Our findings suggest a new strategy to enhance the photostability of near-infrared dyes and dye-sensitized upconversion nanohybrids.

Low blue-hazard white-light emission based on color-tunable triplet-triplet annihilation upconversion

The commonly used artificial light sources, such as fluorescent lamps and white light-emitting diodes, often have a high ratio of blue light emission, which poses potential blue light hazards, especially one of the main culprits leading to eye diseases. Therefore, developing novel white lighting sources with low blue-hazard is highly appreciated. In this work, an air-stable and color-tunable triplet–triplet annihilation upconversion (TTA-UC) mechanism was proposed to realize the low blue-hazard white-light emission. The proposed design was composed of three primary RGB colors from the annihilator (9,10-diphenylanthracene, DPA), the laser excitation source, and the photosensitizer (palladium (II) octaetylporphyrin, PdOEP), respectively. The introduction of oil-in-water (o/w) microemulsion can effectively block the potential oxygen-induced triplet-quenching and benefit high UC efficiency. Moreover, either raising ambient temperatures or adding isobutanol can activate the UC process to yield white-light emission. Notably, the white-light emission with a Commission Internationale de l’Eclairage (CIE) coordinate of (0.33, 0.33) as well as a low ratio of blue emission (14.2 %) was achieved at an ambient temperature of 42 °C. Therefore, the proposed air-stable TTA-UC mechanism can significantly lower the blue-hazard and provide a novel solution for applications in lighting and display.

Investigation on a high-quality health laser light source based on the age of lighting users.

The optimal laser spectrum for users of all ages is determined by considering the health implications of laser lighting across different age groups. We present a theoretical calculation model for age-related blue light hazard (BLH) and Circadian Action Factor (CAF), establishing optimization criteria that integrate visual and health factors. Health assessments of white laser light source spectra, obtained from the combination of RGB-LDs, were conducted using BLH and CAF at various illumination color temperatures. Based on our proposed comprehensive optimization criteria, white-light laser sources with high luminous efficacy (LER ≥ 330 lm/W), good color rendering (Ra ≥ 70), and color coordinates within the quadrangle region specified by the ANSI C78.377-2008 standard were obtained. This research provides a theoretical foundation for the personalized design and application of high-quality, healthy laser light sources for users of different ages.

Spectral transmission of commercially available high-energy visible light-filtering spectacle lenses.

High-energy visible (HEV) light-filtering spectacle lenses are being widely promoted despite limited evidence to support their use. The spectral transmission properties of commercially available lenses varied, particularly in the HEV light region, and they do not perform in the same way for transmission of ultraviolet (UV)-A and HEV light. Although HEV light is important for several visual and nonvisual functions, there are concerns over the potential adverse effects of increased HEV light exposure. High-energy visible light-filtering spectacle lenses are being widely marketed to promote ocular health and improve sleep by reducing exposure to HEV light. This study reports on the spectral transmission characteristics of commercially available HEV light-filtering spectacle lenses based on the recommendations of the Spectral Bands Task Force technical report. The spectral transmission of light through nine afocal plastic lenses, including eight commercially available HEV light-filtering lenses and one clear uncoated control lens, was evaluated using a Cary 5000 UV-Vis-NIR spectrophotometer (Agilent Technologies, Johannesburg, South Africa) for wavelengths 250 to 780 nm. The percentage transmission values are reported for UV radiation and visible light, with emphasis for HEV light (380 to 500 nm) and the three subbands therein. All lenses blocked UV-C and UV-B radiation (250 to 315 nm). For UV-A radiation (315 to 380 nm), six lenses showed optimal 100% absorption, whereas three lenses allowed ≤12%. The transmission values for the HEV light-filtering lenses ranged from 55 to 90% and 75 to 95% for HEV light of wavelengths 400 to 455 nm and 455 to 500 nm, respectively. In contrast, the control lens showed 92 (400 to 455 nm) and 93% (455 to 500 nm) transmission. The HEV light-filtering spectacle lenses varied in their transmission properties and do not necessarily perform in the same way for transmission of UV-A and HEV light. Optometric personnel should consider these transmission properties, particularly for HEV light, when making recommendations to patients about HEV light-filtering spectacle lenses.

A Sensitive Lead-Free Perovskite Photodetector for Self-Powered Blue Light Hazard Detection Application

A Sensitive Lead-Free Perovskite Photodetector for Self-Powered Blue Light Hazard Detection Application

Comparative Study of the Phytochemical Profile and Biological Activity of Ajuga reptans L. Leaf and Root Extracts

In this work, the phytochemical composition and the biological activity of the ethanolic extracts obtained from Ajuga reptans L. (Lamiaceae) leaves and roots (growing in Lesser Poland Voivodeship, Poland) were compared. The phytochemical composition of the extracts were determined by the high-performance liquid chromatography with diode-array detection (HPLC–DAD) method. The dominant compounds in both extracts were verbacoside, isoverbacoside, 3,4-dihydroxyphenylacetic acid and rosmarinic acid. The antioxidant capacity of the extracts was evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and 2,2’-azobis(3-ethylbenzothiazoline-6-sulfonate (ABTS) tests. The Folin–Ciocalteu assay was used to determine the total polyphenolic content. Additionally, enzyme (tyrosinase, collagenase) inhibition tests and metal chelating ability were studied to assess the anti-aging properties of the extracts. Moreover, the A. reptans extracts’ capacity to absorb the whole range of ultraviolet radiation and high-energy visible (HEV) light was evaluated. The skin irritation test (SIT) EpiDerm was applied to evaluate the safety of the bugle extracts. The noteworthy point is that there is a lack of literature on the assessment of A. reptans root extract activity. Our study is the only one that compares the quantitative composition and biological activity of extracts from the root and leaves of A. reptans. The obtained results indicated that both of the extracts exhibit high antioxidant, chelating and photoprotective activity, but the extract from A. reptans roots showed a higher enzyme inhibition effect for mature skin. The A. reptans root extract, similarly to the leaf extract, could be applied as potentially multi-functional, safe and sensitive cosmetic raw materials, especially in anti-aging and anti-pollution cosmetics.

Proposal and practicality of an alternative blue-light hazard risk assessment method for high-intensity white-light sources at workplaces

Objectives. It is prescribed to determine blue-light hazard (BLH) weighted radiances, L B , for an assessment of spotlights with an angular subtense α ≥ 11 mrad . The BLH weighted irradiance, E B , can be used alternatively for smaller sources. Appropriate instruments are not common among persons commissioned with risk assessment (RA), and especially L B measurements may be challenging. Therefore, a practical BLH RA approach is proposed that is based on illuminance, E v , pre-calculated blackbody BLH efficacies of luminous radiation, K B,v Planck , and solid angle considerations. Methods. The practicality of this method was examined and compared against other RA approaches. Results. To ensure comparability of the applied instruments, measurements were performed close to a radiance standard, showing deviations within the lamp’s expanded uncertainties ( < 4 % ), whereas the deviations were ± 15 % for longer distances. Focusing on a complex light-emitting diode (LED) spotlight, all detected values could be converted to L B by means of the RA methods within ± 20 % . Two field tests with several spotlights yielded maximum permissible exposure durations (MPED) obtained from the different RA approaches that agreed among each other within uncertainties largely below ± 30 % . Conclusion. The general practicality of the proposed E v method can be concluded for a workplace BLH RA of white-light sources.

Spectral Dependence of Light Exposure on Retinal Pigment Epithelium Disruption in Living Primate Retina.

RPE disruption with light exposures below or close to the American National Standards Institute (ANSI) photochemical maximum permissible exposure (MPE) have been observed, but these findings were limited to two wavelengths. We have extended the measurements across the visible spectrum. Retinal imaging with fluorescence adaptive optics scanning light ophthalmoscopy (FAOSLO) was used to provide an in vivo measure of RPE disruption at a cellular level. The threshold retinal radiant exposures (RREs) for RPE disruption (localized detectable change in the fluorescence image) were determined at 460, 476, 488, 530, 543, 561, 594, 632, and 671nm (uniform 0.5° square exposure) using multiples locations in 4 macaques. FAOSLO is sensitive in detecting RPE disruption. The visible light action spectrum dependence for RPE disruption with continuous wave (CW) extended field exposures was determined. It has a shallower slope than the current ANSI blue-light hazard MPE. At all wavelengths beyond 530nm, the disruption threshold is below the ANSI blue-light hazard MPE. There is reciprocity of exposure irradiance and duration for exposures at 460 and 594nm. We measured with FAOSLO the action spectrum dependence for photochemical RPE disruption across the visible light spectrum. Using this in vivo measure of phototoxicity provided by FAOSLO, we find that thresholds are lower than previously measured. The wavelength dependence in our data is considerably shallower than the spectral dependence of the traditional ANSI blue-light hazard, emphasizing the need for more caution with increasing wavelength than expected.

Blue light impairs the repair of UVB-induced pyrimidine dimers in a human skin model.

In recent years, interest is growing in the biological cutaneous effects of high-energy visible light (400-450 nm). In the present study, we explored the impact of blue light (BL) on the repair of pyrimidine dimers, the major class of premutagenic DNA damage induced by exposure to sunlight. We unambiguously demonstrate that the exposure of invitro reconstructed human epidermis to environmentally relevant doses of BL strongly decreases the rate of repair of cyclobutane pyrimidine dimers and pyrimidine (6-4) pyrimidone photoproducts induced by a subsequent UVB irradiation. Using the highly sensitive and specific liquid chromatography-tandem mass spectrometry assay, we did not observe induction of pyrimidine dimers by BL alone. Finally, we showed that application, during the BL exposure step, of a formula containing a new filter, named TriAsorB and affording BL photoprotection, prevented the decrease in DNA repair efficiency. These results emphasize the potential deleterious effects of BL on DNA repair and the interest in providing adequate skin protection against this wavelength range of sunlight.

The blue light hazard and its use on the evaluation of photochemical risk for domestic lighting. An in vivo study

BackgroundNowadays artificial light highly increases human exposure to light leading to circadian rhythm and sleep perturbations. Moreover, excessive exposure of ocular structures to photons can induce irreversible retinal damage. Meta-analyses showed that sunlight exposure influences the age of onset and the progression of Age-related macular degeneration (AMD), the leading cause of blindness in people over fifty-year old. Currently, the blue-light hazard (BLH) curve is used in the evaluation of the phototoxicity of a light source for domestic lighting regulations. ObjectivesHere, we analyze the phototoxicity threshold in rats and investigate the role played by the light spectrum, assessing the relevance of the use of the BLH-weighting to define phototoxicity. MethodsWe exposed albino rats to increasing doses of blue and white light, or to lights of different colors to evaluate the impact of each component of the white light spectrum on phototoxicity. Cellular mechanisms of cell death and cellular stress induced by light were analyzed. ResultsOur results show that the phototoxicity threshold currently accepted for rats is overestimated by a factor of 50 when considering blue light and by a factor of 550 concerning white light. This is the result of the toxicity induced by green light that increases white light toxicity by promoting an inflammatory response. The content of green in white light induces 8 fold more invasion of macrophages in the retina than the content of blue light. Moreover, the use of BLH-weighting does not evaluate the amount of red radiations contained in white light that mitigates damage by inhibiting the nuclear translocation of L-DNase II and reducing by 33% the number of TUNEL-positive cells. DiscussionThese findings question the current methods to determine the phototoxicity of a light source and show the necessity to take into account the entire emission spectrum. As current human phototoxicity thresholds were estimated with the same methods used for rats, our results suggest that they might need to be reconsidered.

Hazards associated with blue light emitted during gas metal arc welding of mild steel using various shielding gases and currents

Blue light emitted during arc welding is known to potentially cause photoretinopathy. To help prevent retinal injury, it is important to identify the hazards associated with various welding conditions. The present work conducted experiments involving gas metal arc welding of mild steel under various conditions, and measured the spectral radiance of the arcs. The effective radiance values, as used by the American Conference of Governmental Industrial Hygienists (ACGIH) to quantify exposure level of blue light, were subsequently calculated from the data. The resulting values were in the range of 5.0-118 W/cm2/sr, corresponding to hazardous levels according to ACGIH guidelines. The effective radiance was increased at higher welding currents and when pulsed currents were used rather than steady currents. The blue light hazard was also affected by the type of shielding gas employed. These data confirm that it is very hazardous to stare at arcs during gas metal arc welding of mild steel. As such, appropriate eye protection is necessary during arc welding, and directly staring at the arc should be avoided.

A circadian lighting method for low blue light hazard, high color rendering index, and tunable circadian stimulus

A circadian lighting method for low blue light hazard, high color rendering index, and tunable circadian stimulus

Indenopyrene and Blue-Light Co-Exposure Impairs the Tightly Controlled Activation of Xenobiotic Metabolism in Retinal Pigment Epithelial Cells: A Mechanism for Synergistic Toxicity.

High energy visible (HEV) blue light is an increasing source of concern for visual health. Polycyclic aromatic hydrocarbons (PAH), a group of compounds found in high concentrations in smokers and polluted environments, accumulate in the retinal pigment epithelium (RPE). HEV absorption by indeno [1,2,3-cd]pyrene (IcdP), a common PAH, synergizes their toxicities and promotes degenerative changes in RPE cells comparable to the ones observed in age-related macular degeneration. In this study, we decipher the processes underlying IcdP and HEV synergic toxicity in human RPE cells. We found that IcdP-HEV toxicity is caused by the loss of the tight coupling between the two metabolic phases ensuring IcdP efficient detoxification. Indeed, IcdP/HEV co-exposure induces an overactivation of key actors in phase I metabolism. IcdP/HEV interaction is also associated with a downregulation of proteins involved in phase II. Our data thus indicate that phase II is hindered in response to co-exposure and that it is insufficient to sustain the enhanced phase I induction. This is reflected by an accelerated production of endogenous reactive oxygen species (ROS) and an increased accumulation of IcdP-related bulky DNA damage. Our work raises the prospect that lifestyle and environmental pollution may be significant modulators of HEV toxicity in the retina.