Combating Blue Light Pollution With Flavonoids: Implications for Environmental Health and Aging.

CIRCADIAN MISALIGNMENT AS AN ENDOPHENOTYPE FOR DEPRESSION

Blue-light filtering ophthalmic lenses: to prescribe, or not to prescribe?

Visible light is present everywhere in our lives. Widespread use of computers and smartphones has increased the daily time spent in front of screens. What effect does this visible light have on us? Recent studies have shown that short-wavelength blue light (400-450nm) irradiation, similar to UV, inhibits the cell proliferation and differentiation, induces the intracellular oxidative stress, promotes the cell apoptosis and causes some other negative effects. However, it's unusual that directly face to such short-wavelength and high-energy blue light in daily life. Therefore, the effects of blue light with longer wavelength (470nm), lower energy (1, 2 J/cm2) and multiple times (simulated daily use) exposure on cells have been studied in this experiment. In our results, low energy density multiple blue light inhibited cell proliferation and metastatic capability with a weak phototoxicity. Blue light also promoted intracellular reactive oxygen species and caused DNA damage. Furthermore, the melanin synthesis was also promoted by low energy density multiple blue light exposure. Together, these results indicate that longer wavelength and low energy density blue light multiple exposure is still harmful to our cells. Furthermore, prolonged exposure to screens likely induces dull skin through induction of melanin synthesis. These results further mentioned us should paid more attention to controlling the daily use of digital device.

Visible light is present everywhere in our lives. Widespread use of computers and smartphones has increased the daily time spent in front of screens. What effect does this visible light have on us? Recent studies have shown that short-wavelength blue light (400-450nm) irradiation, similar to UV, inhibits the cell proliferation and differentiation, induces the intracellular oxidative stress, promotes the cell apoptosis and causes some other negative effects. However, it’s unusual that directly face to such short-wavelength and high-energy blue light in daily life. Therefore, the effects of blue light with longer wavelength (470nm), lower energy (1, 2 J/cm2) and multiple times (simulated daily use) exposure on cells have been studied in this experiment. In our results, low energy density multiple blue light inhibited cell proliferation and metastatic capability with a weak phototoxicity. Blue light also promoted intracellular reactive oxygen species and caused DNA damage. Furthermore, the melanin synthesis was also promoted by low energy density multiple blue light exposure. Together, these results indicate that longer wavelength and low energy density blue light multiple exposure is still harmful to our cells. Furthermore, prolonged exposure to screens likely induces dull skin through induction of melanin synthesis. These results further mentioned us should paid more attention to controlling the daily use of digital device.

BackgroundWith the popularity of blue-rich light-emitting diode (LED)-backlit display devices, our eyes are now exposed to more short-wavelength blue light than they were in the past. The goal of this study was to investigate the pathogenesis of cataracts after short-wavelength light exposure.MethodsSprague-Dawley (SD) rats were selected and randomly divided into a control group (10 rats each for the 4-, 8-, and 12-week groups) and an experimental group (10 rats each for the 4-, 8-, and 12-week groups). The rats in the experimental group were exposed to a short-wavelength blue LED lamp for 12 h per day. After exposure to the blue LED lamp, the rats were maintained in total darkness for 12 h, after which a 12-h light/dark cycle was resumed. The intensity of the lamp was 3000 lx. At the end of the short-wavelength blue LED lamp exposure (for 4, 8, and 12 weeks), the expression levels of caspase-1, caspase-11 and gasdermin D (GSDMD) were examined in rat lens epithelial cells (LECs) using qRT-PCR and Western blot analyses. An illuminance of 2500 lx was used to study the potential effect of blue LED light on HLE-B3 hLECs in vitro. AC-YVAD-CMK, a caspase-1 inhibitor, was used to confirm the pyroptosis of LECs by flow cytometry.ResultsAfter 6 weeks, cataracts developed in the experimental rats (4/20 eyes). The clarity of the lens gradually worsened with the duration of exposure. Twelve weeks later, all of the rat eyes had developed cataracts. The expression levels of caspase-1, caspase-11 and GSDMD at 4, 8, and 12 weeks were significantly higher in the samples from rats exposed to a short-wavelength blue LED lamp than in the samples from control rats (p<0.05). The proportions of double-positive hLECs were significantly increased in the 5-h and 10-h short-wavelength blue light exposure subgroups compared with the 5-h and 10-h caspase-1 inhibitor subgroups (p < 0.05).ConclusionThe data indicate that pyroptosis plays a key role in cataract induction after short-wavelength blue light exposure. This study might provide new insights into a novel pathogenic mechanism of cataracts.

Reviews on Various Fields of Blue Light Action.- The Biological Significance and Evolution of Photosensory Systems.- Short Wavelength Light in Invertebrate Visual Sense Cells - Pigments, Potentials and Problems.- Bacteriorhodopsin and its Position in the Blue Light Syndrome.- Chemical Modification of Bacteriorhodopsin by Phenylisothiocyanate: Effect on the Photocycle.- Effects of Blue Light on Movement of Microorganisms.- Blue Light-Induced Intracellular Movements.- Phytochrome and Non-Phytochrome Dependent Blue Light Effects on Intracellular Movements in Fresh-Water Algae.- Interaction Between Blue Light and Phytochrome in Photomorphogenesis.- Sensory Transduction in Phycomyces Photoresponses.- Regulation of Cell Growth and Cell Cycle by Blue Light in Adiantum Gametophytes.- Blue Light and Transcription.- Photoreceptors and Primary Reactions.- Spectroscopic and Photochemical Characterization of Flavoproteins and Carotenoproteins as Blue Light Photoreceptors.- Carotenoids as Primary Photoreceptors in Blue-Light Responses.- On the Nature of the Blue Light Photoreceptor: Still an Open Question.- Conformational Changes Caused by Blue Light.- Interactions of Flavins with Cytochrome C and Oxygen in Excited Artificial Systems.- Artificial Flavin/Membrane Systems a Possible Model for Physiological Blue Light Action.- Effects of UV and Blue Light on the Bipotential Changes in Etiolated Hypocotyl Hooks of Dwarf Beans.- Blue Light-Controlled Conidiation and Absorbance Change in Neurospora are Mediated by Nitrate Reductase.- Phototropism in Phycomyces: a Photochromic Sensor Pigment?.- Blue and Near Ultraviolet Reversible Photoreaction in Conidial Development of Certain Fungi.- Blue Light Responses in the Siphonaceous Alga Vaucheria.- Cis to Trans Photoisomerization of ?-Carotene in Euglena gracilis Var. bacillaris W3BUL: Further Purification and Characterization of the Photoactivity.- Carotenogenesis.- Blue Light-Induced Carotenoid Biosynthesis in Microorganisms.- Photokilling and Protective Mechanisms in Fusarium aquaeductuum.- Dose Response and Related Aspects of Carotenogenesis in Neurospora crassa.- Carbon Metabolism and Respiration.- Effects of Blue Light on Respiration and Non-Photosynthetic CO2 Fixation in Chlorella vulgaris 11h Cells.- Effect of Blue Light on CO2 Fixation in Heterotrophically Grown Scenedesmus obliquus Mutant C-2A'.- Light-Induced Carbon Metabolism in an Early Stage of Greening in Wild Type and Mutant C-2A' Cells of Scenedesmus obliquus.- Enhancement of Carbohydrate Degradation by Blue Light.- Blue Light-Effects on Enzymes of the Carbohydrate Metabolism in Chlorella. 1. Pyruvate Kinase.- Blue Light-Effects on Enzymes of the Carbohydrate Metabolism in Chlorella. 2. Glyceraldehyde 3-Phosphate Dehydrogenase (NADP-Dependent).- Blue Light-Induced Enhancement in Activity of Certain Enzymes in Heterotrophically Grown Cultures of Scenedesmus obliquus.- Effect of 360 nm Light on RuBPCase Products in Vitro - Role of Copper in the Reaction.- The Photoinactivation of Micro-Algal Ribulose Bisphosphate Carboxylase its Physiological and Ecological Significance.- A Rhythmic Change in the Enhancement of the Dark Respiration of Chlorella fusca Induced by a Short Blue-Light Exposure of Low Intensity.- Interaction Between Blue Light and Nitrogen Metabolism.- Regulation by Monochromatic Light of Nitrate Uptake in Chlorella fusca.- Flavin-Mediated Photoreduction of Nitrate by Nitrate Reductase of Higher Plants and Microorganisms.- Effects of Ammonia on Carbon Metabolism in Photosynthesizing Chlorella vulgaris 11 h: the Replacement of Blue Light by Ammonium Ion.- Comparative Studies on the Effect of Ammonia and Blue Light on the Regulation of Photosynthetic Carbon Metabolism in Higher Plants.- The Effect of Blue and Red Light on the Content of Chlorophyll, Cytochrome f, Soluble Reducing Sugars, Soluble Proteins and the Nitrate Reductase Activity During Growth of the Primary Leaves of Sinapis alba.- Chloroplast Development.- Blue Light Effects on Plastid Development in Higher Plants.- Blue Light-Induced Development of Thylakoid Membranes in Isolated Seedling Roots and Cultured Plant Cells.- The Effect of Light Quality and the Mode of Illumination on Chloroplast Development in Etiolated Bean Leaves.- The Importance of Blue Light for the Development of Sun-Type Chloroplasts.- Blue Light and the Photocontrol of Chloroplast Development in Euglena.- Effects of Blue Light on Greening in Microalgae.- Blue Light Regulation of Chloroplast Development in Scenedesmus Mutant C-2A'.- The Action of Blue Light on 5-Aminolevulinic Acid Formation.- Physiology of Blue Light Effects.- Blue-Light Photomorphogenesis in Mushrooms (Basidiomycetes).- Blue Light Induced Differentiation in Phycomyces blakesleeanus.- Effect of Blue Light on Metabolic Processes, Development and Movement in True Slime Molds.- Blue-Light Photoreception in the Inhibition and Synchronization of Growth and Transport in the Yeast Saccharomyces.- Role of Light at Shorter Wavelength in Photobiological Phenomena in Blue-Green Algae.- Blue Light Effects on Some Algae Collected from Subsurface Chlorophyll Layer in the Western Pacific Ocean.- Visible and Spectrophotometrically Detectable Blue Light Responses of Maize Roots.- Synergistic Action of Red and Blue Light on Stomatal Opening of Vicia faba Leaves.- The Blue Light Response of Stomata and the Green Vacuolar Fluorescence of Guard Cells.- Light Induced Changes in the Centrifugability of Chloroplasts Mediated by an Irradiance Dependent Interaction of Respiratory and Photosynthetic Processes.- Growth Rate Patterns Which Produce Curvature and Implications for the Physiology of the Blue Light Response.- Organism Index.

Background and Purpose: The photo pigment melanopsin initiates cell depolarization in response to highintensity, short-wavelength light. Antecedent long-wavelength light may potentiate regeneration of the melanopsin photo pigment, We investigated the influence of red or blue exposure on the pupil response to subsequent blue light. Methods: Nine healthy subjects were examined using chromatic pupillometry. With a sequence of 3 consecutive blue exposures or a sequence in which the middle exposure was red light, both sequences repeated in the darkadapted state. The summed pupil response during light was obtained as the area under the curve and the percentage difference (diff %) between the first and last blue stimulus was calculated for each sequence. Findings: The pupil response to the third blue exposure was greater than to first blue light. No significant difference was seen in the diff% when comparing a sequence with a blue intervening versus red intervening light, in the light adapted (P = 0.39) or dark adapted state (P = 0.58). Conclusion: Prior light exposure enhances the pupil response to subsequent blue light stimulation, no differential effect was found between blue and red light. This study suggests that antecedent light history is important when designing protocols and evaluating results of chromatic pupillometry.

Previous studies have shown that short-wavelength blue visible light induces retinal injury and may be a risk factor for age related macular degeneration. A2E is a blue light absorbing retinal chromophore that accumulates with age. Our previous in vitro studies have determined that, although A2E itself has a low phototoxic efficiency, the oxidation products of A2E that are formed in the presence of visible light can contribute to observed retinal pigment epithelial photodamage. The purpose of this study was to investigate the effects of blue light on retinal phototoxicity and its relationship to A2E, oxidized A2E and its isomers. Sprague-Dawley albino rats were dark adapted for 24 h. Control rats remained in the dark while experimental rats were exposed to blue light (λ = 450 nm, 3.1 mW cm(-2)) for 6 h. Isolated retinas were homogenized in Folch extraction mixture and then in chloroform. The dried extracts were reconstituted and divided for determination of organic soluble compound. Esters of fatty acids were determined with GC-MS, A2E and other chromophores using HPLC, and A2E oxidation products with LC-MS. Exposure of rat eyes to blue light did not significantly change the fatty acid composition of the retina. The A2E concentration (normalized to fatty acid content) in blue light exposed animals was found to be lower than the A2E concentration in control rats. The concentrations of all-trans-retinal-ethanolamine adduct and iso-A2E a precursor and an isomer of A2E respectively, were also lower after blue-light exposure than in the retinas of rats housed in the dark. On the other hand, the amount of oxidized forms of A2E was higher in the animals exposed to blue light. We conclude that in the rat eye, blue-light exposure promotes oxidation of A2E and iso-A2E to the products that are toxic to retinal tissue. Although high concentrations of A2E may be cytotoxic to the retina, the phototoxicity associated with blue light damage to the retina is in part a result of the formation of toxic A2E oxides. This effect may partially explain the association between blue light induced retinal injury and macular degeneration.

Are there advantages in implanting a yellow IOL to reduce the risk of AMD?

PurposeTo investigate whether suppression of blue light can improve visual function in patients with short tear break up time (BUT) dry eye (DE).MethodsTwenty-two patients with short BUT DE (10 men, 12 women; mean age, 32.4 ± 6.4 years; age range, 23–43 years) and 18 healthy controls (10 men, 8 women; mean age, 30.1 ± 7.4 years; age range, 20–49 years) underwent functional visual acuity (VA) examinations with and without wearing eyeglasses with 50% blue light blocked lenses. The functional VA parameters were starting VA, functional VA, and visual maintenance ratio.ResultsThe baseline mean values (logarithm of the minimum angle of resolution, logMAR) of functional VA and the visual maintenance ratio were significantly worse in the DE patients than in the controls (P < 0.05), while no significant difference was observed in the baseline starting VA (P > 0.05). The DE patients had significant improvement in mean functional VA and visual maintenance ratio while wearing the glasses (P < 0.05), while there were no significant changes with and without the glasses in the control group (P > 0.05),ConclusionsProtecting the eyes from short-wavelength blue light may help to ameliorate visual impairment associated with tear instability in patients with DE. This finding represents a new concept, which is that the blue light exposure might be harmful to visual function in patients with short BUT DE.

Short-wavelength blue light is commonly found in daily life and is harmful to health. In this experiment, we investigated the effect of luteolin on the survival time of Drosophila under the blue light condition of 3000 Lux using Drosophila as the model organism. The results showed that luteolin alleviated the damage suffered by Drosophila under blue light irradiation, significantly prolonged the survival time of Drosophila, prolonged the survival time of male Drosophila in the heat stress assay, increased the activity of female Drosophila in the spontaneous activity assay, and increased the egg production of female Drosophila at the highest concentration, and there was no significant difference in the food intake experiment. We suggest that the increase in survival time of Drosophila under blue light conditions is due to the function of luteolin in resisting oxidative stress.

The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of ~40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention.

In patients with outer retinal degeneration, a differential pupil response to long wavelength (red) versus short wavelength (blue) light stimulation has been previously observed. The goal of this study was to quantify differences in the pupillary re-dilation following exposure to red versus blue light in patients with outer retinal disease and compare them with patients with optic neuropathy and with healthy subjects. Prospective comparative cohort study. Twenty-three patients with outer retinal disease, 13 patients with optic neuropathy and 14 normal subjects. Subjects were tested using continuous red and blue light stimulation at three intensities (1, 10 and 100 cd/m2) for 13 s per intensity. Pupillary re-dilation dynamics following the brightest intensity was analysed and compared between the three groups. The parameters of pupil re-dilation used in this study were: time to recover 90% of baseline size; mean pupil size at early and late phases of re-dilation; and differential re-dilation time for blue versus red light. Patients with outer retinal disease showed a pupil that tended to stay smaller after light termination and thus had a longer time to recovery. The differential re-dilation time was significantly greater in patients with outer retinal disease (median = 28.0 s, P < 0.0001) compared with controls and patients with optic neuropathy. A differential response of pupil re-dilation following red versus blue light stimulation is present in patients with outer retinal disease but is not found in normal eyes or among patients with visual loss from optic neuropathy.

Short-wavelength blue light contributes to the pyroptosis of human lens epithelial cells (hLECs)

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