Blue Light Exposure: Ocular Hazards and Prevention-A Narrative Review

Betahistine mesylate reduces the damage of blue light exposure in Drosophila model

Previous studies have demonstrated the efficacy of betahistine mesylate in treating vertigo and angioneurotic headache, enhancing microcirculation, and facilitating histamine release. However, limited research has been conducted on the drug's potential in mitigating blue light-induced damage. Thus, this study utilized Drosophila as the model organism and employed the Siler model to investigate the impact of various concentrations of betahistine mesylate on the lifespan, under 3000 lx blue light irradiation. At the same time we measure food intake, spontaneous activity, and sleep duration of Drosophila. The findings of this study indicate that a high concentration of betahistine mesylate can decrease the initial mortality (b0) in male flies, mitigating the damage of blue light to Drosophila. Consequently, this delays the aging process in male Drosophila and extends their average lifespan. After betahistine mesylate ingestion, locomotor activity upon blue light exposure decreased significantly in male Drosophila. In conclusion, this study offers initial evidence supporting the investigation of the regulatory mechanisms of betahistine mesylate on lifespan and its potential anti-blue light effects.

The role of the SIRT1/NF-κB/NLRP3 pathway in the pyroptosis of lens epithelial cells under shortwave blue light radiation

Cataracts are the world's number one blinding eye disease. Cataracts can only be effectively treated surgically, although there is a chance of surgical complications. One of the pathogenic processes of cataracts is oxidative stress, which closely correlated with pyroptosis. SIRT1 is essential for the regulation of pyroptosis. Nevertheless, the role of SIRT1 in formation of cataracts is unclear. In this work, we developed an in vitro model of shortwave blue light (SWBL)-induced scotomization in human lens epithelial cells (HLECs) and an in vivo model of SWBL-induced cataracts in rats. The study aimed to understand how the SIRT1/NF-κB/NLRP3 pathway functions. Additionally, the evaluation included cell death and the release of lactate dehydrogenase (LDH), a cytotoxicity marker, from injured cells. First, we discovered that SWBL exposure resulted in lens clouding in Sprague- Dawley (SD) rats and that the degree of clouding was positively linked to the duration of irradiation. Second, we discovered that SIRT1 exhibited antioxidant properties and was connected to the NF-κB/NLRP3 pathway. SWBL irradiation inhibited SIRT1 expression, exacerbated oxidative stress, and promoted nuclear translocation of NF-κB and the activation of the NLRP3 inflammasome, which caused LEC pyroptosis and ultimately led to cataract formation. Transient transfection to increase the expression of SIRT1 decreased the protein expression levels of NF-κB, NLRP3, caspase-1, and GSDMD, inhibited HLEC pyroptosis, and reduced the release of LDH, providing a potential method for cataract prevention and treatment.

Sleep onset time as a mediator in the association between screen exposure and aging: a cross-sectional study

Excessive screen exposure has become a significant health concern. This study investigates the impact of screen time on aging in middle-aged and elderly populations. Healthy working adults over 45 years old in Shanghai, China, underwent general and ocular examinations. Questionnaires collected demographics, medical history, and screen exposure details. Aging was assessed using the retinal age gap, defined as the difference between the retinal age predicted by deep learning algorithms based on fundus images and chronological age. Pathway analysis tested the mediation effect of sleep duration and onset time on the relationship between screen usage and retinal age gap. The retinal age gap increased with longer screen exposure, from 0.49 ± 3.51 years in the lowest tertile to 5.13 ± 4.96 years in the highest tertile (Jonckheere-Terpstra test, p < 0.001). Each additional hour of screen exposure accelerated the retinal age gap by 0.087 years (95% CI, 0.027, 0.148, p = 0.005) in the fully adjusted linear model. Sleep onset time mediated the impact of screen usage on the retinal age gap (indirect effect, β = 0.11; 95% CI 0.04-0.24). The impact of screen usage in a light-off environment on the retinal age gap was fully mediated by sleep onset time (indirect effect, β = 0.22; 95% CI 0.07-0.38), with the proportion being 100%. Our study identified a correlation between excessive screen time and a wider retinal age gap in middle-aged and elderly individuals, likely due to delayed sleep onset. To mitigate the adverse effects on the retina and aging, it is important to limit screen usage and avoid screens before bedtime.

Perovskite-Doped Modulated Color-Selective Photosynaptic Transistors for Target Object Recognition

The processing of multicolor noisy images in visual neuromorphic devices requires selective absorption at specific wavelengths; however, it is difficult to achieve this because the spectral absorption range of the device is affected by the type of material. Surprisingly, the absorption range of perovskite materials can be adjusted by doping. Herein, a CdCl2 co-doped CsPbBr3 nanocrystal-based photosensitive synaptic transistor (PST) is reported. By decreasing the doping concentration, the response of the PST to short-wavelength light is gradually enhanced, and even weak light of 40 μW·cm-2 can be detected. Benefiting from the excellent color selectivity of the PST device, the device array is applied to feature extraction of target blue items and removal of red and green noise, which results in the recognition accuracy of 95% for the noisy MNIST data set. This work provides new ideas for the application of novel transistors integrating sensors and storage computing.

Violet Light Effects on the Circadian Rest-Activity Rhythm and the Visual System

BACKGROUND

Rooms illuminated by "black light" (<400 nm wavelength) has become popular, but there is not enough scientific evidence to support its implementation. This study aims to assess the effects of violet light (392 nm) on the circadian rest-activity rhythm and the visual system through animal experimentation.

MATERIALS AND RESULTS

Five groups of four mice were exposed to different white light, violet light, and dark periods, and their circadian rhythm was analyzed by measuring the circadian period using rest-activity cycles. Electroretinographic recordings and structural analysis of the retina were also performed on experimental animals.

RESULTS

Our study demonstrates that mice present normal circadian activity during exposure to violet light, taking rest not only under white light but under violet lighting periods. However, mice suffered a decrease in electrical retinal response after exposure to violet light as measured by electroretinography. Nevertheless, no structural changes were observed in the retinas of the animals under different lighting conditions.

CONCLUSIONS

Violet light elicits circadian rest-activity rhythm in mice but alters their visual function, although no structural changes are observed after short periods of violet light exposure.

Comparison of the Performance of ChatGPT, Claude and Bard in Support of Myopia Prevention and Control

Purpose

 Chatbots, which are based on large language models, are increasingly being used in public health. However, the effectiveness of chatbot responses has been debated, and their performance in myopia prevention and control has not been fully explored. This study aimed to evaluate the effectiveness of three well-known chatbots-ChatGPT, Claude, and Bard-in responding to public health questions about myopia.

Methods

 Nineteen public health questions about myopia (including three topics of policy, basics and measures) were responded individually by three chatbots. After shuffling the order, each chatbot response was independently rated by 4 raters for comprehensiveness, accuracy and relevance.

Results

 The study's questions have undergone reliable testing. There was a significant difference among the word count responses of all 3 chatbots. From most to least, the order was ChatGPT, Bard, and Claude. All 3 chatbots had a composite score above 4 out of 5. ChatGPT scored the highest in all aspects of the assessment. However, all chatbots exhibit shortcomings, such as giving fabricated responses.

Conclusion

 Chatbots have shown great potential in public health, with ChatGPT being the best. The future use of chatbots as a public health tool will require rapid development of standards for their use and monitoring, as well as continued research, evaluation and improvement of chatbots.

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

SIGNIFICANCE

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.

PURPOSE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Polydopamine Nanoparticles as Mimicking RPE Melanin for the Protection of Retinal Cells Against Blue Light-Induced Phototoxicity

Exposure of the eyes to blue light can induce the overproduction of reactive oxygen species (ROS) in the retina and retinal pigment epithelium (RPE) cells, potentially leading to pathological damage of age-related macular degeneration (AMD). While the melanin in RPE cells absorbs blue light and prevents ROS accumulation, the loss and dysfunction of RPE melanin due to age-related changes may contribute to photooxidation toxicity. Herein, a novel approach utilizing a polydopamine-replenishing strategy via a single-dose intravitreal (IVT) injection is presented to protect retinal cells against blue light-induced phototoxicity. To investigate the effects of overexposure to blue light on retinal cells, a blue light exposure Nrf2-deficient mouse model is created, which is susceptible to light-induced retinal lesions. After blue light irradiation, retina degeneration and an overproduction of ROS are observed. The polydopamine-replenishing strategy demonstrated effectiveness in maintaining retinal structural integrity and preventing retina degeneration by reducing ROS production in retinal cells and limiting the phototoxicity of blue light exposure. These findings highlight the potential of polydopamine as a simple and effective replenishment for providing photoprotection against high-energy blue light exposure.

The effect of Fernblock® in preventing blue-light-induced oxidative stress and cellular damage in retinal pigment epithelial cells is associated with NRF2 induction

Blue light exposure of the ocular apparatus is currently rising. This has motivated a growing concern about potential deleterious effects on different eye structures. To address this, ARPE-19 cells were used as a model of the retinal pigment epithelium and subjected to cumulative expositions of blue light. The most relevant cellular events previously associated with blue-light-induced damage were assessed, including alterations in cell morphology, viability, cell proliferation, oxidative stress, inflammation, and the induction of DNA repair cellular mechanisms. Consistent with previous reports, our results provide evidence of cellular alterations resulting from repeated exposure to blue light irradiation. In this context, we explored the potential protective properties of the vegetal extract from Polypodium leucotomos, Fernblock® (FB), using the widely known treatment with lutein as a reference for comparison. The only changes observed as a result of the sole treatment with either FB or lutein were a slight but significant increase in γH2AX+ cells and the raise in the nuclear levels of NRF2. Overall, our findings indicate that the treatment with FB (similarly to lutein) prior to blue light irradiation can alleviate blue-light-induced deleterious effects in RPE cells, specifically preventing the drop in both cell viability and percentage of EdU+ cells, as well as the increase in ROS generation, percentage of γH2AX+ nuclei (more efficiently with FB), and TNF-α secretion (the latter restored only by FB to similar levels to those of the control). On the contrary, the induction in the P21 expression upon blue light irradiation was not prevented neither by FB nor by lutein. Notably, the nuclear translocation of NRF2 induced by blue light was similar to that observed in cells pre-treated with FB, while lutein pre-treatment resulted in nuclear NRF2 levels similar to control cells, suggesting key differences in the mechanism of cellular protection exerted by these compounds. These results may represent the foundation ground for the use of FB as a new ingredient in the development of alternative prophylactic strategies for blue-light-associated diseases, a currently rising medical interest.

Streptococcus thermophilus iHA318 Improves Dry Eye Symptoms by Mitigating Ocular Surface Damage in a Mouse Model

Dry eye is a complicated ocular surface disease that causes discomfort, visual disturbance, and frequently observed ocular surface damage. Emerging hypotheses suggest probiotics may help relieve dry eye symptoms by modulating inflammation and oxidative stress. This study aimed to investigate the therapeutic effects of Streptococcus thermophilus iHA318 probiotics on dry eye using in vitro assays and an in vivo murine model of ultraviolet B (UVB) radiation-induced dry eye. In vitro analyses revealed that S. thermophilus iHA318® exhibited antioxidant activity and anti-inflammatory effects by inhibiting reactive oxygen species production and suppressing inflammatory cytokines. For the in vivo study, female ICR mice were assigned to normal control, UVB-induced dry eye, and UVB+iHA318 treatment groups. UVB exposure significantly decreased tear volume and tear film breakup time (TBUT) compared to normal controls. Supplementation with S. thermophilus iHA318® via oral gavage markedly improved tear production and TBUT on day 7 post-UVB exposure. Ocular surface photography demonstrated improved gradings of corneal opacity, smoothness, and lissamine green staining in the iHA318 group versus the UVB group. Topographical analysis further revealed improvement in the UVB-induced corneal irregularities by iHA318 treatment. Collectively, these results indicate that S. thermophilus iHA318 exerts a protective effect against dry eye symptoms by mitigating oxidative stress and inflammation, thereby preserving tear film stability and ocular surface integrity. This probiotic strain represents a promising therapeutic approach for managing dry eye syndrome.

Red-light-mediated copper-catalyzed photoredox catalysis promotes regioselectivity switch in the difunctionalization of alkenes

Controlling regioselectivity during difunctionalization of alkenes remains a significant challenge, particularly when the installation of both functional groups involves radical processes. In this aspect, methodologies to install trifluoromethane (-CF3) via difunctionalization have been explored, due to the importance of this moiety in the pharmaceutical sectors; however, these existing reports are limited, most of which affording only the corresponding β-trifluoromethylated products. The main reason for this limitation arises from the fact that -CF3 group served as an initiator in those reactions and predominantly preferred to be installed at the terminal (β) position of an alkene. On the contrary, functionalization of the -CF3 group at the internal (α) position of alkenes would provide valuable products, but a meticulous approach is necessary to win this regioselectivity switch. Intrigued by this challenge, we here develop an efficient and regioselective strategy where the -CF3 group is installed at the α-position of an alkene. Molecular complexity is achieved via the simultaneous insertion of a sulfonyl fragment (-SO2R) at the β-position. A precisely regulated sequence of radical generation using red light-mediated photocatalysis facilitates this regioselective switch from the terminal (β) position to the internal (α) position. Furthermore, this approach demonstrates broad substrate scope and industrial potential for the synthesis of pharmaceuticals under mild reaction conditions.

Exploring the metabolic implications of blue light exposure during daytime in rats

Excessive exposure to light is a global issue. Artificial light pollution has been shown to disrupt the body's natural circadian rhythm. To investigate the impacts of light on metabolism, we studied Sprague-Dawley rats chronically exposed to red or blue light during daytime or nighttime. Rats in the experimental group were exposed to extended light for 4 hours during daytime or nighttime to simulate the effects of excessive light usage. Strikingly, we found systemic metabolic alterations only induced by blue light during daytime. Furthermore, we conducted metabolomic analyses of the cerebrospinal fluid, serum, heart, liver, spleen, adrenal, cerebellum, pituitary, prostate, spermatophore, hypothalamus and kidney from rats in the control and blue light exposure during daytime. Significant changes in metabolites have been observed in cerebrospinal fluid, serum, hypothalamus and kidney of rats exposed to blue light during daytime. Metabolic alterations observed in rats encompassing pyruvate metabolism, glutathione metabolism homocysteine degradation, phosphatidylethanolamine biosynthesis, and phospholipid biosynthesis, exhibit analogous patterns to those inherent in specific physiological processes, notably neurodevelopment, cellular injury, oxidative stress, and autophagic pathways. Our study provides insights into tissue-specific metabolic changes in rats exposed to blue light during the daytime and may help explain potential mechanisms of photopathogenesis.

Effect of Light Sources on Transmittance of Commercially Available Contact Lenses

BACKGROUND

Previous studies have suggested that light rays may interact with contact lenses, potentially affecting their transmittance.

AIM

This study aimed to investigate the effects of visible and ultraviolet (UV)-A light sources on the transmittance of some commercially available daily, weekly, and monthly contact lenses.

METHODS

Nine commercially available soft contact lenses were irradiated with a solar simulator, light-emitting diode (LED) source, laser source, and UV-A source. The average transmittance of the tested lenses before and after irradiation in the UV, visible, and infrared light wavelength ranges was determined using an Agilent UV-visible spectrophotometer, model 8453.

RESULTS

The results showed a partial or complete block of UV transmission at the UV-B region (300 nm) and the UV-A region (355 nm) by the Bio true daily contact lens, as well as the Acuvue Oasys, Avaira, and Biomedics 55 weekly lenses. At the visible region (555 nm), irradiation of the contact lenses by different light sources resulted in reduced light transmittance. At the infrared region (900 nm), the weekly and monthly contact lenses partially blocked infrared transmission, while the daily lenses showed either increased or decreased infrared transmission.

CONCLUSIONS

Solar and artificial lighting, as well as high-powered lasers, constitute a major concern on the contact lenses' light transmission and optical properties. It is essential to develop soft contact lenses that have photoprotective properties while maintaining visible light transmittance.

Dendrobium nobile Polysaccharide Attenuates Blue Light-Induced Injury in Retinal Cells and In Vivo in Drosophila

Blue light is the higher-energy region of the visible spectrum. Excessive exposure to blue light is known to induce oxidative stress and is harmful to the eyes. The stems of Dendrobium nobile Lindl. (Orchidaceae), named Jinchaishihu, have long been used in traditional Chinese medicine (TCM) for nourishing yin, clearing heat, and brightening the eyes. The polysaccharide is one of the major components in D. nobile. However, the effect on ocular cells remains unclear. This study aimed to investigate whether the polysaccharide from D. nobile can protect the eyes from blue light-induced injury. A crude (DN-P) and a partially purified polysaccharide (DN-PP) from D. nobile were evaluated for their protective effects on blue light-induced damage in ARPE-19 and 661W cells. The in vivo study investigated the electroretinographic response and the expression of phototransduction-related genes in the retinas of a Drosophila model. The results showed that DN-P and DN-PP could improve blue light-induced damage in ARPE-19 and 661W cells, including cell viability, antioxidant activity, reactive oxygen species (ROS)/superoxide production, and reverse opsin 3 protein expression in a concentration-dependent manner. The in vivo study indicated that DN-P could alleviate eye damage and reverse the expression of phototransduction-related genes, including ninaE, norpA, Gαq, Gβ76C, Gγ30A, TRP, and TRPL, in a dose-dependent manner in blue light-exposed Drosophila. In conclusion, this is the first report demonstrating that D. nobile polysaccharide pretreatment can protect retinal cells and retinal photoreceptors from blue light-induced damage. These results provide supporting evidence for the beneficial potential of D. nobile in preventing blue light-induced eye damage and improving eyesight.

NIR-II fluorescence imaging without intended excitation light

Nowadays, second near-infrared window (NIR-II) dyes are almost excited by laser diodes, but none of the white light (400-700 nm) excited NIR-II imaging has been studied because of the lack of suitable optical probes. Herein, a novel blue-shifted NIR-II dye, TPA-TQT, has been selected for use in multi-wavelength white light emitting diode (LED) excited NIR-II imaging. This white LED barely caused photo-quenching of the dyes, especially indocyanine green (ICG), whereas the ICG's brightness decreased by 90% under continuous 808 nm laser irradiation. Compared to single-wavelength LED, multi-wavelength LED showed a lower background and similar signal-to-background ratios. This system provided high image resolution to identify blood vessels (103 μm), lymphatic capillaries (129.8 μm), and to monitor hindlimb ischemia-reperfusion and lymphatic inflammation. Furthermore, white LED excited NIR-II fluorescence imaging-guided surgery (FIGS) was successfully performed in 4T1 tumor-bearing mice. Impressively, the lighting LED-based NIR-II FIGS was found to clearly delineate small lesions of metastatic tumors of about ∼350 μm diameter and further was able to guide surgical removal. Overall, multi-wavelength LED-based NIR-II imaging is a promising imaging strategy for tumor delineation and other biomedical applications.

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

Purpose

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.

Methods

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 671 nm (uniform 0.5° square exposure) using multiples locations in 4 macaques.

Results

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 530 nm, the disruption threshold is below the ANSI blue-light hazard MPE. There is reciprocity of exposure irradiance and duration for exposures at 460 and 594 nm.

Conclusions

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 and intraocular lenses (IOLs): Beliefs and realities]

The first intraocular lenses (IOLs) used for cataract surgery transmitted both ultraviolet (UV) radiation and visible light to the retina. Colorless UV-blocking IOLs were introduced and rapidly adopted in the 1980s. Yellow-tinted blue-blocking (also known as blue-filtering) IOLs were marketed in the early 1990s. Blue-blocking IOLs were intended to simulate age-related crystalline lens yellowing to reduce the cyanopsia that some patients experienced after cataract surgery. When blue-filtering IOLs were introduced in North America, however, blue-blocking chromophores were advocated as a way to protect patients from age-related macular degeneration (AMD) despite the lack of evidence that normal environmental light exposure causes AMD. The "blue light hazard" is a term that describes the experimental finding that acute, abnormally intense light exposures are potentially more phototoxic to the retina when short rather than long wavelengths are used. Thus, in brief exposures to intense light sources such as welding arcs, ultraviolet radiation is more hazardous than blue light, which is more hazardous than longer wavelength green or red light. International commissions have cautioned that the blue light hazard does not apply to normal indoor or outdoor light exposures. Nonetheless, the hazard is used for commercial purposes to suggest misleadingly that ambient environmental light can cause acute retinal phototoxicity and increase the risk of AMD. Very large epidemiological studies show that blue-blocking IOLs do not reduce the risk or progression of AMD. Additionally, blue-filtering IOLs or spectacles cannot decrease glare disability, because they decrease image and glare illuminance in the same proportion. Blue light is essential for older adults' scotopic photoreception needed to reduce the risk of nighttime falling and related injuries. It is also critical for circadian photoreception that is essential for good health, sleep and cognitive performance. Unfortunately, age-related pupillary miosis, retinal rod and ganglion cell photoreceptor degeneration and decreased outdoor activity all reduce the amount of healthful blue light available to older adults. Blue-restricting IOLs further reduce the available blue light at a time when older adults need it most. Patients and ophthalmologists are exposed to hypothesis-based advertisements for blue-filtering optical devices that suppress short wavelength light critical for vision in dim lighting and for good physical and mental health. Spectacle and intraocular lens selections should be based on scientific fact, not conjecture. Ideal IOLs should improve photoreception rather than limit it permanently. Practice efficiency, surgical convenience and physician-manufacturer relationships may eliminate a patient's opportunity to choose between colorless blue-transmitting IOLs and yellow-tinted, blue-restricting IOLs. Cataract surgeons ultimately determine whether their patients have the opportunity to make an informed choice about their future photoreception.

Applications of Ultraviolet and Sub-ultraviolet Dermatoscopy in Neoplastic and Non-neoplastic Dermatoses: A Systematic Review

Dermatoscopy is a non-invasive and cost-efficient imaging technique augmenting clinical examination in neoplastic and non-neoplastic dermatoses. Recently, novel dermatoscopic techniques based on principles of reflectance/absorption and excited fluorescence have been developed. However, comprehensive data on their applications are sparse, and terminology is inconsistent. In this systematic review, we addressed the principles of ultraviolet (UV) imaging and proposed categorization based on spectral characteristics and signal acquisition, as well as discussed documented and potential clinical applications, safety measures during examination, and limitations associated with reflectance and fluorescence dermatoscopy. A literature search was conducted in the PubMed medical database until 2 December 2023 according to PRISMA guidelines, and 28 papers fit the scope of this review, whereas additional relevant articles were included to provide broader context regarding the chosen terminology, chromophores described, safety of sub-UV/UV, and regulations for light-emitting devices. UV and sub-UV dermatoscopy, categorized into different methods on the basis of the emitted wavelength and signal acquisition process (reflectance versus fluorescence), augment conventional dermatoscopy by optimizing safety margins in melanoma, facilitating early detection of tumor recurrence, and enhancing visualization in non-neoplastic conditions, including pigmentation disorders, intertrigo, papulo-desquamative dermatoses, and beyond. The review highlights the limitations of these techniques, including difficulty in differentiating melanin from hemoglobin, challenges in evaluating uneven surfaces, and artifacts. Although UV dermatoscopy complements conventional dermatoscopy, clinicians should be aware of their peculiarities, artifacts, limitations, and safety concerns to optimize their diagnostic accuracy and ensure patient's safety.

A meta-analysis of randomized controlled trials evaluating the effectiveness and safety of the repeated low-level red light therapy in slowing the progression of myopia in children and adolescents

PURPOSE

The aim of this study was to evaluate the effectiveness and safety of repeated low-level red light (RLRL) therapy in controlling myopia progression in children through a meta-analysis.

METHODS

We searched several databases including PubMed, Embase, The Cochrane Library, Web of Science, CNKI, WANFANG, CBM, and VIP with languages restricted to both Chinese and English. The search was conducted from the establishment of the databases to March 23, 2023. We collected randomized controlled trials and controlled experiments to evaluate changes in axial length (AL) and spherical equivalent (SE) before and after RLRL intervention. Two researchers performed literature screening and data extraction, and RevMan software (Ver 5.3) and StataMP 17.0 were used for meta-analysis.

RESULTS

A total of 141 articles were retrieved, and finally, six randomized controlled trials met the inclusion and exclusion criteria, including 820 eyes (RLRL group: 411 eyes, control group: 409 eyes). The meta-analysis results showed that the RLRL group was significantly better than the control group in controlling AL, and the difference between the two groups was statistically significant (mean difference [MD] = -0.22, 95% confidence interval [CI] [ - 0.28, -0.16]; P < 0.001). The RLRL group was also better than the control group in terms of SE, and the difference between the two groups was statistically significant (MD = 0.46, 95% CI [0.32, 0.6]; P < 0.001). Five studies reported adverse reactions in the RLRL group, and two cases stopped treatment due to the feeling of too bright light, while the others had no significant side effects in the short term.

CONCLUSION

RLRL therapy is a safe and effective method for controlling myopia, which can inhibit the growth of AL and slow down the progression of myopia. However, further research and validation are needed to determine its treatment efficacy and course.

Immunocytochemical Analysis of Crocin against Oxidative Stress in Trigeminal Sensory Neurons Innervating the Cornea

Corneal diseases are a major cause of vision loss, often associated with aging, trauma and disease. Damage to corneal sensory innervation leads to discomfort and pain. Environmental stressors, such as short-wavelength light, can induce oxidative stress that alters mitochondrial function and affects cell and tissue homeostasis, including corneal innervation. Cellular antioxidant mechanisms may attenuate oxidative stress. This study investigates crocin, a derivative of saffron, as a potential antioxidant therapy. In vitro rat trigeminal sensory ganglion neurons were exposed to both sodium azide and blue light overexposure as a model of oxidative damage. Crocin was used as a neuroprotective agent. Mitochondrial and cytoskeletal markers were studied by immunofluorescence analysis to determine oxidative damage and neuroprotection. In vivo corneal innervation degeneration was evaluated in cornea whole mount preparations using Sholl analyses. Blue light exposure induces oxidative stress that affects trigeminal neuron mitochondria and alters sensory axon dynamics in vitro, and it also affects corneal sensory innervation in an in vivo model. Our results show that crocin was effective in preserving mitochondrial function and protecting corneal sensory neurons from oxidative stress. Crocin appears to be a promising candidate for the neuroprotection of corneal innervation.

Blue Light Damage and p53: Unravelling the Role of p53 in Oxidative-Stress-Induced Retinal Apoptosis

In the digital age, the widespread presence of electronic devices has exposed humans to an exceptional amount of blue light (BL) emitted from screens, LEDs, and other sources. Studies have shown that prolonged exposure to BL could have harmful effects on the visual system and circadian rhythm regulation. BL is known to induce oxidative stress, leading to DNA damage. Emerging research indicates that BL may also induce cell death pathways that involve the tumor-suppressor protein p53. Activated p53 acts as a transcription factor to regulate the expression of genes involved in cell cycle arrest, DNA repair, and apoptosis. This study aimed to explore the implication of p53 in BL-caused retinal damage, shedding light on the potential mechanisms of oxidative-stress-induced retinal diseases. BL-exposed porcine retinal cultures demonstrated increased p53- and caspase-mediated apoptosis, depending on exposure duration. Direct inhibition of p53 via pifithrin α resulted in the prevention of retinal cell death. These findings raise concerns about the long-term consequences of the current daily BL exposure and its potential involvement in various pathological conditions, including oxidative-stress-based retinal diseases like age-related macular degeneration. In addition, this study paves the way for the development of novel therapeutic approaches for oxidative-stress-based retinal diseases.

Trimethylated chitosan-coated flexible liposomes with resveratrol for topical drug delivery to reduce blue-light-induced retinal damage

LED-related blue-light-induced damage can cause eye diseases. However, drug delivery in patients with ocular diseases is faced with various challenges. In this study, we developed flexible liposomes based on trimethylated chitosan (TMC-Lipo) to deliver resveratrol for the treatment of retinal diseases. Flexible liposomes can easily cross various biological barriers. Chitosan and its derivatives have adhesive properties and are widely used in mucoadhesive drug delivery systems. Therefore, we wrapped flexible liposomes with trimethylated chitosan via electrostatic adsorption. The charge of the flexible liposomes became positive after encapsulation in TMC, and they remained stable in artificial tears. We assessed the safety of TMC-Lipo in cellular and zebrafish experiments and found that it can be safely used. In addition, treatment with TMC-Lipo significantly reduced H2O2-induced damage to ARPE-19 cells, restored mitochondrial membrane potential, and protected the cells. TMC-Lipo more easily reached the posterior ocular segment of the mice than liposome nanoparticles and attenuated blue-light-induced retinal cytopathy. Our study demonstrates that effective eye drop formulations can be developed based on trimethylated chitosan, which provides a promising approach for the treatment of ocular diseases.

Screening of genes interacting with high myopia and neuropsychiatric disorders

Clinical studies have demonstrated an association between high myopia (HM) and neuropsychiatric disorders; however, the underlying mechanism of the association is not clear. We used whole exome sequencing (WES) in combination with the Genetic Variants Classification Criteria and Guidelines published by the American College of Medical Genetics (ACMG) and bioinformatics analysis to clarify the interrelationship between candidate genes. Causative genes for ocular diseases (45.38%) followed by neuropsychiatric disorders (22.69%) accounted for the highest proportion of genes that exhibited high pathogenicity in HM patients were found. Four pathogenic gene mutations were identified according to ACMG guidelines: c.164_165insACAGCA and c.C1760T in POLG, c.G1291A in COL5A1, and c.G10242T in ZNF469. Three causative genes for neuropsychiatric diseases, PTPRN2, PCDH15 and CDH23, were found to fall at the HM locus. The above results suggest that these genes may interact in high myopia and neuropsychiatric diseases.

Managing Corneal Infections: Out with the old, in with the new?

There have been multiple reports of eye infections caused by antibiotic-resistant bacteria, with increasing evidence of ineffective treatment outcomes from existing therapies. With respect to corneal infections, the most commonly used antibiotics (fluoroquinolones, aminoglycosides, and cephalosporines) are demonstrating reduced efficacy against bacterial keratitis isolates. While traditional methods are losing efficacy, several novel technologies are under investigation, including light-based anti-infective technology with or without chemical substrates, phage therapy, and probiotics. Many of these methods show non-selective antimicrobial activity with potential development as broad-spectrum antimicrobial agents. Multiple preclinical studies and a limited number of clinical case studies have confirmed the efficacy of some of these novel methods. However, given the rapid evolution of corneal infections, their treatment requires rapid institution to limit the impact on vision and prevent complications such as scarring and corneal perforation. Given their rapid effects on microbial viability, light-based technologies seem particularly promising in this regard.

Astaxanthin protects human ARPE-19 retinal pigment epithelium cells from blue light-induced phototoxicity by scavenging singlet oxygen

Age-related macular degeneration (AMD) is one of an increasing number of diseases that causes irreversible impairment and loss of vision in the elderly. AMD occurs by oxidative stress-mediated apoptosis of retinal pigment epithelium cells. The onset of AMD may be positively correlated with the exposure to blue light. We screened food-derived carotenoids for cytoprotective action against blue light irradiation using human ARPE-19 retinal pigment epithelium cells. This study revealed that blue light irradiation triggered apoptosis and oxidative stress in all-trans-retinal (atRAL)-exposed ARPE-19 cells by generating singlet oxygen (1O2), leading to significant cell death. We found that astaxanthin, a potent anti-oxidative xanthophyll abundant in several marine organisms including microalgae, salmon, and shrimp, significantly suppresses blue light-induced apoptotic cell death of atRAL-exposed ARPE-19 cells by scavenging 1O2. Mechanistic studies using the blue-light irradiated cells also demonstrated that the cytoprotective effects of astaxanthin can be attributed to scavenging of 1O2 directly. Our results suggest the potential value of astaxanthin as a dietary strategy to prevent blue light-induced retinal degeneration including AMD.

Nutritional Factors: Benefits in Glaucoma and Ophthalmologic Pathologies

Glaucoma is a chronic optic neuropathy that can lead to irreversible functional and morphological damage if left untreated. The gold standard therapeutic approaches in managing patients with glaucoma and limiting progression include local drops, laser, and/or surgery, which are all geared at reducing intraocular pressure (IOP). Nutrients, antioxidants, vitamins, organic compounds, and micronutrients have been gaining increasing interest in the past decade as integrative IOP-independent strategies to delay or halt glaucomatous retinal ganglion cell degeneration. In our minireview, we examine the various nutrients and compounds proposed in the current literature for the management of ophthalmology diseases, especially for glaucoma. With respect to each substance considered, this minireview reports the molecular and biological characteristics, neuroprotective activities, antioxidant properties, beneficial mechanisms, and clinical studies published in the past decade in the field of general medicine. This study highlights the potential benefits of these substances in glaucoma and other ophthalmologic pathologies. Nutritional supplementation can thus be useful as integrative IOP-independent strategies in the management of glaucoma and in other ophthalmologic pathologies. Large multicenter clinical trials based on functional and morphologic data collected over long follow-up periods in patients with IOP-independent treatments can pave the way for alternative and/or coadjutant therapeutic options in the management of glaucoma and other ocular pathologies.