A rapid single session invivo method to quantify blue light protection using immediate pigmentation darkening.

There are numerous cosmetic ingredients that have been identified to have blue light protection benefits. The urge to learn more about blue light protection claims has led to several substantiation test methods that can be utilized by companies to prove product efficacy. PartII of this article provides up-to-date information on cosmetic ingredients that can provide protection from blue light, and methods companies can use to substantiate blue light protection claims. An Internet search was completed using the Google Scholar database and a cosmetic ingredient supplier database (UL Prospector) for ingredients and relevant literature. Multiple ingredient categories, for example, algae-derived ingredients, UV filters, botanical extracts, antioxidants, and vitamins, are available on the market to fight against blue light-induced skin damage. There is not a formal standardized method to test for blue light protection; however, spectrophotometers, imaging devices, measuring oxidative stress, and visual evaluations are some of the methods being used today. The number of ingredients launched for blue light protection and new methods developed to test products for blue light protection claims is expected to increase in the near future as we are learning more about the mechanism of damage that occurs in the skin upon blue light exposure.

Blue light from electronic devices enriched with a peak at 456nm affects circadian rhythm and antioxidant balance of skin, necessitating the study of photoprotection against the 456-nm blue light. This study aims to report that blue light (456nm) can cause skin pigmentation and proposes a new clinical evaluation method for blue light (456nm) protection based on the skin pigmentation level. We developed a clinical device (ABC deviceTM ) that emitsblue light (peak=456nm). Based on the minimal persistent pigment darkening dose (MPPD) determined from visual evaluation and melanin index measurements, we proposed the "protection grade of blue light (PB)" guideline to assess the protective ability of skin against blue light. Human skin irradiated with blue light (456nm) showed a light dose-dependent degree of pigmentation. The MPPD on unprotected and protected skin was 135J/cm2 or 180J/cm2 and 135-225J/cm2 , respectively. The ABC device™ and the proposed clinical method were used to test the four blue light blocking assessments of TiO2 . Consequently, the inorganic filter with TiO2 effectively blocked the blue light (456nm). The AP product demonstrated the ability to block blue light by 1.15 times (PB=1.15), which significantly lowered the melanin index of the skin after irradiation as compared to that of the unprotected skin (P<.001). We propose an objective clinical evaluation method for blue light protection. This study elucidates the properties of blue light blockers for customers suffering from blue light pollution.

Constant exposure to blue light emanating from screens, lamps, digital devices, or other artificial sources at night can suppress melatonin secretion, potentially compromising both sleep quality and overall health. Daytime exposure to elevated levels of blue light can also lead to permanent damage to the eyes. Here, we have developed blue light protective plasmonic contact lenses (PCLs) to mitigate blue light exposure. Crafted from poly(hydroxyethyl methacrylate) (pHEMA) and infused with silver nanoparticles, these contact lenses serve as a protective barrier to filter blue light. Leveraging the plasmonic properties of silver nanoparticles, the lenses effectively filtered out the undesirable blue light (400-510 nm), demonstrating substantial protection (22-71%) while maintaining high transparency (80-96%) for the desirable light (511-780 nm). The maximum protection level reaches a peak of 79% at 455 nm, aligned with the emission peak for the blue light sourced from LEDs in consumer displays. The presence of silver nanoparticles was found to have an insignificant impact on the water content of the developed contact lenses. The lenses maintained high water retention levels within the range of 50-70 wt %, comparable to commercial contact lenses. The optical performance of the developed lenses remains unaffected in both artificial tears and contact lens storage solution over a month with no detected leakage of the nanoparticles. Additionally, the MTT assay confirmed that the lenses were biocompatible and noncytotoxic, maintaining cell viability at over 85% after 24 h of incubation. These lenses could be a potential solution to protect against the most intense wavelengths emitted by consumer displays and offer a remedy to counteract the deleterious effects of prolonged blue light exposure.

Blue light is emitted visible light between the wavelengths of 400 to 500nm. The main source of blue light is sunlight, but digital screens, light-emitting diodes (LEDs), and fluorescent lighting serve as additional sources. Concerns about the negative effects of blue light on the skin have rapidly increased over the past 15years, and consequently, the urge to learn more about this topic is increasing as well. Part I of this article provides up-to-date information on the definition of blue light and the negative and positive effects of blue light on the skin. An Internet search was completed using the Google scholar database for relevant literature. Blue light can be both harmful and beneficial to the skin, depending on intensity and wavelength. Short-term safety information is more readily available from clinical studies; however, the biological effects of repeated and/or longer-term exposure are not fully understood yet. Low-energy and low exposure times to high-energy blue light can help prevent skin diseases, while studies have revealed that longer exposure to high-energy blue light can increase the amount of DNA damage, cell and tissue death, and injury, eye damage, skin barrier damage, and photoaging.

The widespread use of electronic devices has led to increased blue light exposure, highlighting the need for effective radiation blockers with blue light protection. Two synthetic 2-(2'-hydroxyphenyl)benzoxazole derivatives named azo-4'-benzoxazole and azo-5'-benzoxazole have shown an unprecedented blue light absorption capacity but had not been subjected to a safety evaluation. This study aimed to evaluate the cytotoxic, genotoxic, and mutagenic activities of these compounds. The cytotoxic and genotoxic activities were evaluated using MTT assay and comet assay in L929 fibroblast cells. Salmonella/microsome assay and micronucleus test were performed to detect gene and chromosomal mutations. The IC50 was 87.9 μg/mL for azo-4'-benzoxazole and 79.5 μg/mL for azo-5'-benzoxazole. In the Salmonella/microsome assay, the azo-5'-benzoxazole compound induced frameshift mutations in the TA97a strain in the presence of metabolic activation (S9 mix), while azo-4'-benzoxazole did not show mutagenic activities in all five strains tested. The azo-5'-benzoxazole showed genotoxic and mutagenic effects in L929 cells that were probably associated to the cleavage of azo-5' into its analogs 2-(4'-amino-2'-hydroxyphenyl)benzoxazole and 2-amino-1-naphthol. In conclusion, the azo-substituted group at the 5' position of the phenyl ring appears to have greater toxicological risks than substituents at the 4' position of 2-(phenyl)benzoxazole. The findings warrant further preclinical studies to ensure the safety of these compounds for use as blue light filters.

The field of sun protection is quickly changing and the research article by Douki etal., published in the current issue of Photochemistry and Photobiology, reported key experimental data that will certainly help the development of better sun care products. Mutagenic photoproducts (CPDs, cyclobutane pyrimidine dimers and 6-4PPs, pyrimidine-6-4-pyrimidone photoproducts) were formed in the reconstructed human epidermis (RHE) by UVB (312 nm) irradiation, and their concentrations were detected by HPLC-MS/MS as a function of time after the UVB treatment. RHE had been previously exposed or not (control) to blue light (427 nm). Both CPDs and 6-4PPs were shown to last longer in blue-light irradiated RHE, proving the inhibition of the DNA repair by blue light exposure. This is a highly relevant information because sunscreens allow people to enjoy longer periods under the sun and consequently, to endure very high doses of blue light. The work also reported results obtained with RHEs previously treated with a sunscreen formulation containing a broadband filter that offers blue-light protection. Interestingly, authors observed that the DNA repair was not significantly inhibited in RHE previously treated with the sunscreen offering broadband protection. Readers will find a scientifically sound proof of the importance of blue-light protection in sun care products.

Exposure to blue light emitted by electronic devices has increased substantially in recent years and has been associated with enhanced production of reactive oxygen species (ROS), potentially compromising ocular health. Blue light-filtering devices have been proposed as a strategy to mitigate corneal damage. This study investigated the effects of blue light exposure on the cornea and evaluated the efficacy of a commercially available photoprotective device. Twenty-five C57BL/6 mice were allocated into groups: blue light exposure with photoprotection (2-12h/day), without photoprotection (2-12h/day), and a control group maintained under ambient laboratory lighting (12h light/dark cycle). Although no statistically significant increase in lipid peroxidation (LPO) was observed, a tendency toward higher LPO levels, along with increased total antioxidant capacity (ACAP) (P = 0,0001) and reduced ROS levels (P = 0,0011) in prolonged exposure groups, suggests activation of a compensatory antioxidant response. This pattern indicates adaptive redox modulation in corneal tissue, in which enhanced antioxidant defenses may temporarily maintain oxidative balance without overt structural damage. Short-term exposure (2h) did not induce morphological corneal alterations within the evaluated period. However, biochemical changes were detected, and the long-term cumulative effects of chronic blue light exposure remain uncertain. Continuous use of blue light-blocking devices may contribute to optimizing corneal protection during prolonged exposure.

Background: To examine the correlation between blue light exposure from digital screens and myopia progression in adolescents over a one-year period. Methods: A prospective observational study was conducted from May 2023 to September 2024, involving 62 adolescents aged 10 to 18 years. Participants underwent baseline and follow-up ophthalmic assessments, including cycloplegic refraction and axial length measurement. Data on screen time, device use, blue light filter usage, and outdoor activity were collected through structured questionnaires. Myopia progression was analyzed in relation to these factors using appropriate statistical methods. Results: Adolescents with more than 4 hours of daily screen time showed significantly greater myopia progression (–0.88 ± 0.30 D/year) compared to those with less than 2 hours (–0.40 ± 0.18 D/year; p = 0.003). Use of blue light filters was associated with slower progression (p = 0.041), and outdoor exposure of at least one hour per day had a protective effect (p = 0.010). Conclusion: Prolonged blue light exposure from digital devices is significantly associated with accelerated myopia progression in adolescents. Promoting screen time limits, blue light protection, and outdoor activity may help reduce this risk.

Updated insights of active cosmetic ingredients against blue light: In vivo and in vitro evidence

Welding curtains and screens are intended to protect workers, other than the welder, from the effects of optical radiation generated by the welding process. The national and international standards for welding screens and curtains have different requirements. The aim is to compare the protection requirements of examples of welding curtain material and to assess compliance with the international and national standards. Spectral transmittance values (ultraviolet, visible, and infrared) of 21 samples were obtained from the records of an ISO/IES 17025 accredited test laboratory and performance/compliance was assessed according to each of the standards. In the ultraviolet, 10 samples passed and seven failed all standards. In the visible/infrared region, four samples passed and 10 failed all standards. Four samples passed the U.S. and international standards but failed the Australian/New Zealand standard in the blue-light transmittance requirement. One sample failed both the U.S. and Australian/New Zealand standards but the result for the international standard was borderline, one sample passed ISO but failed the blue-light requirements, and one failed ISO but passed the blue-light requirements. The derivations of the various requirements are not well documented. The Australia/New Zealand standard is significantly more stringent in the ultraviolet and blue-light regions. A review of the optical radiation hazards and revision of the standards are indicated. It is possible that curtains, other than those tested, that comply with the international standard might transmit hazardous levels of blue light and, conversely, adequate ultraviolet and blue-light protection is available with curtains that do not comply with the international standard.

Premature skin ageing, and skin hyperpigmentation are influenced by exogenous factors, such as ultraviolet radiation and blue light. In this study, we assess the protective effect of a sunscreen (TDF® Blu Voile Sunscreen) in protecting the skin against the harmful effects of blue light irradiation in vivo and through the in situ quantitative and qualitative evaluation of protein carbonylation in human skin explants. The protective effect of the test product against blue light was first evaluated ex vivo on human skin explants. The treated and non-treated explants were exposed to 14 J/cm2 of blue light 460 nm following which the protein carbonylation was evaluated by in situ epifluorescence imaging and separation by high-resolution gel electrophoresis. To determine whether the test product could also protect against the immediate and persistent pigmenting effect of blue light, two randomized in vivo studies were conducted, which included respectively 17 subjects with a skin phototype of IV and V (Fitzpatrick classification) and 22 subjects with a skin phototype of IV, V, and VI (Fitzpatrick classification). The duration of the study for each subject was 2 days (D1 and D2) for immediate observations and 5 days (D1-D5) for persistent observations. Specific zones on the subjects' back were either left non-treated or treated with the test product and were then exposed to a unique dose of blue light 415 nm. The onset of pigmentation between the treated and exposed zones was then assessed relative to the non-exposed treated zone through colorimetric measurements of the Individual Typology Angle (ITAo ). Human skin explants treated with test product showed significantly lower levels of accumulated carbonylated proteins, with a protection of 82%, following exposure to blue light 460 nm. Findings of the in vivo studies also indicated that the test product presented significantly better protective efficacy against immediate and persistent pigmentation induced by blue light 415 nm. Hence, it can be concluded that the test product can protect against the oxidative stress as well as the immediate and persistent pigmentation induced by blue light.

Cytotoxicity and genotoxicity of blue LED light and protective effects of AA2G in mammalian cells and associated DNA repair deficient cell lines

Broad-spectrum sunscreens containing the TriAsorB™ filter: In vitro photoprotection and clinical evaluation of blue light-induced skin pigmentation.

The light spectrum varies with the altitude of the sun and shows different light colors in clear water. In this study, we aimed to investigate the response of juvenile steelhead trout Oncorhynchus mykiss (34.67 ± 2.69 g initial weight) under different light color conditions. The effects of different blue and red light combinations on plasma biochemical parameters, digestive enzyme activity, and RNA/DNA ratio were assessed in trout over 16 weeks. Six treatments were randomly assigned to 24 tanks with four replicates per treatment: a constant light intensity of 150 lx: 12 h white light then 12 h dark (12W); 12 h blue light then 12 h dark (12B); 12 h red light then 12 h dark (12R); 1.5 h blue light, 9 h red light, 1.5 h blue light, then 12 h dark (3B9R); 3 h blue light, 6 h red light, 3 h blue light, then 12 h dark (6B6R); and 12 h of both blue and red light then 12 h dark (T12BR). Fish exposed to the 3B9R light environment showed significantly increased plasma levels of total protein (TP), enhanced activities of midgut lipase, trypsin, and gastric lipase; and increased RNA content in the liver and muscle tissue to promote protein synthesis efficiency, thereby improving digestive and anabolic performance compared to fish in the other treatments. This indicates that steelhead trout have adapted well to such variable light conditions during long-term evolution. In contrast, trout exposed to the 6B6R light environment showed significant reductions in plasma glucose, TP, and triglyceride levels, decreased activity of gastrointestinal digestive enzymes, and reduced protein synthesis capacity in the muscle and liver, resulting in weakened digestive and anabolic performance. Furthermore, despite the high RNA content and RNA/DNA ratio in fish exposed to a 12R light environment, relatively high plasma cholesterol and triglycerides levels were observed, which might indicate oxidative stress. Therefore, this light is not considered suitable for long-term cultivation. In conclusion, the 3B9R treatment was the optimal light condition tested and can be used to improve the digestive and anabolic performance of steelhead trout.

A UV-curable coating with UV and blue light protection was prepared by incorporating modified rare earth nano cerium dioxide (CeO2) treated with the silane coupling agent KH570. The structures of the modified CeO2 and the resulting UV-curable coating were characterized using Fourier Transform Infrared Spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. UV spectral analysis was conducted to evaluate the UV shielding performance of the coating. The results demonstrated that the nano-CeO2 was uniformly distributed within the polymer matrix of the cured coating. The coating exhibited UV shielding capabilities ranging from 58% to 98% in the UVB region (280-315 nm), as well as effective protection against blue light (400-450 nm), and the visible light transmittance is maintained at about 90%. The UV-cured coating also displayed excellent mechanical properties, indicating its potential application in electronic products.