Blue-light Filtering Research Articles

The Effects of Blue Light-Filtering Intraocular Lenses on the Protection and Function of the Visual System.

Filtration of high-energy short-wave visible light (blue light) to improve vision and protect against damage has evolved both in aquatic animals and terrestrial species. In humans, pigments in the inner layer of the macula absorb wavelengths between 400 and 520 nm and function to improve visual performance. In patients who undergo cataract surgery, replacing cataractous lenses with artificial intraocular lenses (IOLs) that do not mimic normal healthy adult lenses could result in preventable negative visual effects, including glare disability. Blue light–filtering (BLF) IOLs were designed to filter short-wave light in addition to ultraviolet light and mimic the natural crystalline lens. Current studies indicate that BLF IOLs may provide protection from blue light–induced retinal damage and slow the development and progression of age-related macular degeneration. Additionally, BLF IOLs have been shown to improve chromatic contrast, reduce photostress recovery time, reduce glare disability and discomfort, and generally improve visual performance under glare conditions. Although a number of concerns have been raised about the relative risks versus the benefits of BLF IOLs, recent studies reported no adverse effects on visual function or contrast under photopic conditions, no long-term effects on color vision, and no detrimental effects on circadian rhythms with BLF IOLs. Based on the current understanding of the field, evidence suggests that BLF IOLs would be returning the eye to a more natural state compared with non-BLF lenses.

The effects of three blue light filter conditions for smartphones on visual fatigue and visual performance

AbstractAlthough blue light filters have been developed to decrease visual fatigue, the decreased screen brightness and contrast ratios inherent in current filtering techniques should be resolved. To address these issues, we developed a blue light filter, named the Eye Care blue light filter. This study investigated the effects of three blue light filtering techniques (the Eye Care blue light filter, an 80% blue light filter application [app], and a 60% blue light filter app) on visual fatigue and task performance. Thirty‐six healthy adults were recruited. Critical fusion frequency, task performance, and subjective visual fatigue scale were used to assess visual perception and task performance. All subjects played a smartphone game for 40 min in each experimental condition. Task performance was better with the Eye Care blue light filter than with the two filter apps. The value of the Eye Care blue light filter is that it immerses the user in a good task performance environment while reducing blue light exposure per unit of time more than is possible with filter apps.

Blue light–filtering and violet light–filtering hydrophobic acrylic foldable intraocular lenses: Intraindividual comparison

To compare the clinical outcomes after cataract surgery and implantation of a blue light-filtering IOL (AcrySof IQ SN60WF) or a violet light-filtering intraocular lens (IOL) (OptiBlue ZCB00V). Four surgical sites in Japan. Prospective case series. One eye of patients with bilateral cataract was randomly allocated to the blue light-filtering IOL and the fellow eye to the violet light-filtering IOL. Visual acuity and contrast sensitivity were assessed over 3months. The incidence of cyanopsia was evaluated using the neutralization method. The study enrolled 110 eyes of 55 patients. There was no significant difference in visual acuity between the two IOLs. Based on the neutralization results 1week postoperatively, 15 cases (27.8%) with the light-filtering IOL and 8 cases (14.8%) with the violent light-filtering IOL had cyanopsia; the difference reached statistical significance (P=.049). After 2weeks, the difference in the incidence of cyanopsia was not significant. Postoperative contrast sensitivity under photopic condition at 1week and 3months and contrast sensitivity under mesopic conditions at 3months were significantly better with the violet light-filtering IOL than with the blue light-filtering IOL (P<.05). The violet light-filtering IOL yielded highly satisfactory clinical outcomes, including reduction of cyanopsia and a potential improvement in contrast sensitivity. The different chromophores of the IOL and its different material and design might have contributed.

Hunger hormone and sleep responses to the built-in blue-light filter on an electronic device: a pilot study.

The aim of the current study was to investigate the effect of the blue-light filtering 'Night Shift' function on the Apple iPad at night and leptin production, perceived hunger levels and markers of sleep quality and quantity in healthy young adults. In a randomised, crossover design, 13 young adults (6 male/7 female) performed three experimental trials. Two of the interventions included one hour of night-time electronic device use; reading on an iPad ~30 cm from eyes, either with (iPad+NS) or without (iPad) the 'Night Shift' blue-light filtering feature turned on. The control trial involved reading a hard-copy book for one hour (CON). Leptin and perceived hunger and tiredness levels were assessed at various time points for the three experimental conditions. Objective sleep indices (actigraphy) and subjective ratings of sleep were recorded. There were no significant interactions for any of the measured variables (p > 0.05). Small to moderate effect sizes were found for perceived sleep quality, with CON (7.3 ± 1.7) having the highest value when compared to iPad+NS (6.6 ± 1.8, d = 0.29) and iPad (5.6 ± 2.3, d = 0.66). Moderate effects were associated with iPad+NS when compared to iPad (d = 0.77) and for iPad compared to CON (d = 0.90) for pre-post change in leptin concentration. Use of electronic devices at night may result in moderate suppression of leptin levels and impaired sleep quality, with negligible differences associated with whether or not the 'Night Shift' feature is turned on.

Effects of the Emitted Light Spectrum of Liquid Crystal Displays on Light-Induced Retinal Photoreceptor Cell Damage.

Liquid crystal displays (LCDs) are used as screens in consumer electronics and are indispensable in the modern era of computing. LCDs utilize light-emitting diodes (LEDs) as backlight modules and emit high levels of blue light, which may cause retinal photoreceptor cell damage. However, traditional blue light filters may decrease the luminance of light and reduce visual quality. We adjusted the emitted light spectrum of LED backlight modules in LCDs and reduced the energy emission but maintained the luminance. The 661W photoreceptor cell line was used as the model system. We established a formula of the ocular energy exposure index (OEEI), which could be used as the indicator of LCD energy emission. Cell viability decreased and apoptosis increased significantly after exposure to LCDs with higher emitted energy. Cell damage occurred through the induction of oxidative stress and mitochondrial dysfunction. The molecular mechanisms included activation of the NF-κB pathway and upregulation of the expression of proteins associated with inflammation and apoptosis. The effect was correlated with OEEI intensity. We demonstrated that LCD exposure-induced photoreceptor damage was correlated with LCD energy emission. LCDs with lower energy emission may, therefore, serve as suitable screens to prevent light-induced retinal damage and protect consumers’ eye health.

The effect of smartphone light on the physiology signal and cognitive function in circadian environment

Many people are constantly exposed to artificial light caused by digital devices such as computer, smartphone, and TV. Prolonged exposure to artificial light disturbs our circadian rhythm, cognitive function and autonomic nervous system (ANS). Therefore, this study aimed to analyze the alterations in physiological signals and cognitive functions following exposure to smartphone light in order to confirm the effects of artificial light on the human body. Normal adults aged from 21 to 28 were engaged in this study. The experiments were conducted in day (10:00~14:00) and night (8:00~12:00) conditions. Experimental subjects were divided into three groups according to smartphone screen brightness; 50%, 100%, and blue light filter (BLF), then used smartphone for 10 min/set (rest time: 5 min) and repeated the task three times. The ANS changes were confirmed using pulse pressure measurement equipment. Short‐term memory (STM), long‐term memory (LTM), and recognition tests were conducted via language memory test (LMT) and visual memory test (VMT). After using smartphone at daytime condition, 50% group shoed significantly increased ANS activity. Also, LTM and recognition were significantly increased in the 50% and BLP group. In night condition, however, BLF group showed increased LTM and recognition. It has been demonstrated by this study that smartphone light may influence ANS, memory, and cognitive functions. Accordingly, blue light filter is recommended when using smartphone to reduce such harmful alterations.Support or Funding InformationFunds: NRF‐2017R1A2A2A01067169, KGM4611821, 2016 Creative Research Program of Inje University, Republic of KoreaThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Effects of Blue Light on Dynamic Vision.

Dynamic vision is crucial to not only animals’ hunting behaviors but also human activities, and yet little is known about how to enhance it, except for extensive trainings like athletics do. Exposure to blue light has been shown to enhance human alertness (Chellappa et al., 2011), perhaps through intrinsically photosensitive retinal ganglion cells (ipRGCs), which are sensitive to motion perception as revealed by animal studies. However, it remains unknown whether blue light can enhance human dynamic vision, a motion-related ability. We conducted five experiments under blue or orange light to test three important components of dynamic vision: eye pursuit accuracy (EPA, Experiment 1), kinetic visual acuity (KVA, Experiment 1 and 2), and dynamic visual acuity (DVA, Experiment 3–5). EPA was measured by the distance between the position of the fixation and the position of the target when participants tracked a target dot. In the KVA task, participants reported three central target numbers (randomly chosen from 0 to 9) moving toward participants in the depth plane, with speed threshold calculated by a staircase procedure. In the DVA task, three numbers were presented along the meridian line on the same depth plane, with motion direction (Experiment 3) and difficulty level (Experiment 4) manipulated, and a blue light filter lens was used to test the ipRGCs contribution (Experiment 5). Results showed that blue light enhanced EPA and DVA, but reduced KVA. Further, DVA enhancement was modulated by difficulty level: blue light enhancement effect was found only with hard task in the downward motion in Experiment 3 and with the low contrast target in Experiment 4. However, this blue light enhancement effect was not caused by mechanism of the ipRGCs, at least not in the range we tested. In this first study demonstrating the relationship between different components of dynamic vision and blue light, our findings that DVA can be enhanced under blue light with hard but not easy task indicate that blue light can enhance dynamic visual discrimination when needed.

Investigating retinal toxicity of a lutein-based dye in a model of isolated and perfused bovine retina

Retidyne™ is a new lutein-based dye for internal limiting membrane staining. It uses the intrinsic staining characteristics of lutein which is already known to act as an antioxidant and blue-light filter in the human retina. We investigated retinal tolerance to different staining times measured by the electroretinogram (ERG) of an isolated and perfused retina whole mount. For functionality, testing bovine retinas were prepared and perfused with an oxygen saturated standard solution and the ERG was recorded until stable b-wave amplitudes were reached. Then the perfusion was stopped and Retidyne™ was applied directly onto the retinal surface for exposure times of 60 or 120s. After restarting the perfusion with standard solution, the ERG amplitudes were monitored for 75min. To investigate the effects on photoreceptor function alone, 1mM asparate was added to block b-waves. For an exposure time of 60s amplitudes of a- and b-waves remained stable throughout the experiment. Exposure times of 120s caused an initial drop of amplitudes that reached statistical significance only for a-waves (a, - 21%, p = 0.047; b, - 14%, p = 0.052). This effect was only seen during the first minutes of the washout and the ERG recovered completely. In the model of isolated and perfused bovine retina, Retidyne™ showed a good safety profile for common intraoperatively used staining times. An initial toxic effect regarding the transient drop of amplitudes cannot be ruled out but the effect might also be explained by the partial blockage of the flashlight due to a more intense staining effect at the beginning of the washout.

In vivo evaluation of a new hydrophobic acrylic intraocular lens in the rabbit model

To evaluate the uveal and capsular biocompatibility as well as positioning stability of a new hydrophobic acrylic intraocular lens (IOL) invivo in the rabbit model and compare it with a commercially available IOL. John A Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Fifteen New Zealand rabbits had the new test IOL(Clareon CNA0T0) implanted in one eye and a control IOL (Acrysof SN60WF) implanted in the contralateral eye. The testIOL is manufactured from a new hydrophobic acrylic material incorporating ultraviolet blocker and blue light filter. Its design is based on the control IOL's platform. The rabbits were followed up with weekly slitlamp evaluations, which assessed inflammatory reactions as well as capsular bag opacification. Anterior chamber depth was measured at 1 and 4weeks post-implantation (high-frequency ultrasound). After 4weeks, the rabbits were killed humanely and the eyes were enucleated. The anterior segment was evaluated from the posterior or Miyake-Apple view, and was then processed for complete histopathology. There were no statistically significant differences between test and control eyes in terms of postoperative inflammation and capsular biocompatibility, including posterior capsule opacification (P=.34, paired t test), and anterior capsule opacification (P=.53, paired t test), as observed during clinical and pathological evaluation. Invivo axial positioning for the test IOL was comparable to the control IOL and stable over time (P=.531 versus P=.788). The new IOL showed biocompatibility and stability comparable to the control IOL.

Blue light suppression alters cytokinin homeostasis in wheat leaves senescing under shading stress

Blue light (BL) suppression accelerates the senescence rate of wheat (Triticum aestivum L.) leaves exposed to shading. In order to study whether this effect involves the alteration of different cytokinin (CK) metabolites, CK-degradation, as well as the expression profile of genes responsible of CK-perception, -inactivation, -reactivation and/or -turnover, leaf segments of 30 day-old plants were placed in boxes containing bi-distilled water and covered with blue (B) or green (G) light filters, which supplied a similar irradiance but differed in the percentage of BL transmitted (G << B). A neutral (N) filter was used as control. When appropriate, different CK metabolites or an inhibitor of CK-degradation were added in order to alter the endogenous CK levels. A rapid decrement of trans-zeatin (tZ) and cis-zeatin (cZ) content was observed after leaf excision, which progressed at a higher rate in treatment G than in the control and B treatments. Senescence progression correlated with an accumulation of glycosylated forms (particularly cZ-derivatives), and an increment of CK-degradation, both of which were slowed in the presence of BL. On the contrary, CK-reactivation (analyzed through TaGLU1-3 expression) was delayed in the absence of BL. When different CK were exogenously supplied, tZ was the only natural free base capable to emulate the senescence-retarding effect of BL. Even though the signaling components involved in the regulation of senescence rate and CK-homeostasis by BL remain elusive, our data suggest that changes in the expression profile and/or functioning of the transcription factor HY5 might play an important role.

Evaluation of the impact of a new selective blue light filter and class 1 UV blocking SiHy lens (75% WC) examining contrast sensitivity and colour perception

Purpose: Changes in lifestyles and the exposure, both at work and leisure time, to smartphones, tablets, screens and led illumination, has raised concerns about the potential harmful effects of blue light. The purpose of this study is to evaluate the impact of a new blue light and UV blocking silicone hydrogel lens measuring contrast sensitivity and colour perception, under photopic and mesopic conditions, and to compare it with same material with no filters.

Intraocular lens power adjustment by a femtosecond laser: In vitro evaluation of power change, modulation transfer function, light transmission, and light scattering in a blue light–filtering lens

To evaluate intraocular lens (IOL) power, modulation transfer function (MTF), light transmission, and light scattering of a blue light-filtering IOL before and after power adjustment by a femtosecond laser obtained through increased hydrophilicity of targeted areas within the optic, creating the ability to build a refractive-index-shaping lens within an existing IOL. John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, USA. Experimental study. Ten CT Lucia 601PY single-piece yellow hydrophobic acrylic IOLs were used in this study. The IOL power and MTF were measured with a power and modulation transfer function device. Light transmission was measured using a Lambda 35 UV-VIS spectrophotometer. Backlight scattering was assessed with a Scheimpflug camera within the IOL substance. All measurements were done with hydrated IOLs. The IOLs were also evaluated under light microscopy (LM) before and after laser adjustment. After laser adjustment, a mean power change of -2.037 diopters was associated with a MTF change of -0.064 and a light transmittance change of -1.4%. Backlight scattering increased within the IOL optic in the zone corresponding to the laser treatment at levels that are not expected to be clinically significant. Treated areas within the optic could be well appreciated under LM without damage to the IOLs. Power adjustment of a commercially available hydrophobic acrylic blue light-filtering IOL by a femtosecond laser produced an accurate change in dioptric power while not significantly affecting the quality of the IOL.

Enhanced resection of primary high-grade gliomas using a combination of intraoperative magnetic resonance imaging and intraoperative fluorescence (5-aminolevulinic acid): A single-centre experience.

The extent of resection (EOR) of a tumor is a proven prognostic factor in patients undergoing surgery for suspected high grade glioma. A few recent publications have shown the importance of intraoperative magnetic resonance imaging (iMRI) with 5-aminolevulinic acid (5-ALA) fluorescence-guidance in order to maximally increase the EOR. The objective of our study was to calculate the effect on survival of patients with high grade gliomas of resection using both iMRI and 5-ALA fluorescence-guidance as intraoperative adjuncts. Thirty-seven patients with gadolinum-enhancing high gliomas on preoperative MRI undergoing surgical excision were included in a prospective study. Surgeries began under white-light conditions. Intermittently, a blue light filter was switched on to search for remaining tumor tissue not visible to the naked eye. When gross total resection (GTR) was thought to have been achieved, iMRI was done to check for any contrast-enhancing part left behind. Surgery was concluded or resumed based on the iMRI findings. Histopathological examination of the tumor tissue was done. All patients underwent immediate postoperative MRI at the end of the surgery to calculate the EOR. Our results showed that out of the total of 37 patients, 17 patients died during the follow up period and 11 patients were still alive. The mean survival was 587.1 days and median survival was 491 days with a range of 342 to 943 days. When we compared these figures with the average survival in patients with a high grade glioma, i.e., 9 to 14 months, it showed that both the above mentioned modalities were very helpful in increasing the EOR, and in turn, the overall survival. The use of iMRI as well as fluorescence-guidance are appropriate methods to improve the extent of resection in surgery of contrast-enhancing gliomas. Best results can be achieved by the complementary use of both modalities.

Zein-derived peptides as nanocarriers to increase the water solubility and stability of lutein.

Zein and its derived peptides have been used as nanocarriers for bioactive components. Lutein, as well as other xanthophylls, are characterized by blue light filtering and anti-oxidant properties. However, lutein is unstable and has low water solubility, poor absorption, and low bioavailability. In order to protect lutein from oxidative degradation, and to enhance its solubility and dispersibility, stability and bioactivity, lutein-loaded zein nanoparticles (LLZ-NP) and zein-derived peptide nanoparticles (LLZ-PEP-NP) were prepared by the solvent diffusion method. Compared to LLZ-NP, LLZ-PEP-NP possessed good physicochemical properties, including particle size, polydispersity index, zeta potential, entrapment efficiency and in vitro stability. Specifically, transmission electron microscopy (TEM) images showed that LLZ-PEP-NP had a spherical form with a nanometric size and lutein was efficiently loaded into zein-derived peptides through self-assembly. Dynamic light scattering (DLS) results demonstrated that LLZ-PEP-NP had a narrow size distribution in the range of 200-300 nm and a decreased zeta potential compared to that of LLZ-NP. The lutein entrapment efficiency (EE%) of LLZ-NP and LLZ-PEP-NP was more than 85%, while LUT-PEP-NP showed higher lutein entrapment efficiency because of the better capacity of peptides bound with lutein. Nanoencapsulation of lutein into LLZ-PEP-NP resulted in a significantly higher solubility compared to nanoencapsulation of lutein into LLZ-NP and free lutein. The stabilities of lutein in zein-derived peptide nanoparticles in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were improved. These results suggest that zein-derived peptides have the potential to be used as nanocarriers to enhance the solubility and stability of lutein, which can further improve its bioavailability.

Blue-light filtering alters angiogenic signaling in human retinal pigmented epithelial cells culture model

BackgroundLight exposure and more specifically the spectrum of blue light contribute to the oxidative stress in Age-related macular degeneration (AMD). The purpose of the study was to establish whether blue light filtering could modify proangiogenic signaling produced by retinal pigmented epithelial (RPE) cells under different conditions simulating risk factors for AMD.MethodsThree experiments were carried out in order to expose ARPE-19 cells to white light for 48 h with and without blue light-blocking filters (BLF) in different conditions. In each experiment one group was exposed to light with no BLF protection, a second group was exposed to light with BLF protection, and a control group was not exposed to light. The ARPE-19 cells used in each experiment prior to light exposure were cultured for 24 h as follows: Experiment 1) Normoxia, Experiment 2) Hypoxia, and Experiment 3) Lutein supplemented media in normoxia. The media of all groups was harvested after light exposure for sandwich ELISA-based assays to quantify 10 pro-angiogenic cytokines.ResultsA significant decrease in angiogenin secretion levels and a significant increase in bFGF were observed following light exposure, compared to dark conditions, in both normoxia and hypoxia conditions. With the addition of a blue light-blocking filter in normoxia, a significant increase in angiogenin levels was observed. Although statistical significance was not achieved, blue light filters reduce light-induced secretion of bFGF and VEGF to near normal levels. This trend is also observed when ARPE-19 cells are grown under hypoxic conditions and when pre-treated with lutein prior to exposure to experimental conditions.ConclusionsFollowing light exposure, there is a decrease in angiogenin secretion by ARPE-19 cells, which was abrogated with a blue light - blocking filter. Our findings support the position that blue light filtering affects the secretion of angiogenic factors by retinal pigmented epithelial cells under normoxic, hypoxic, and lutein-pretreated conditions in a similar manner.

Response to Letter to the Editor

To the Editor: Dr. Mortazavi brought up many important points regarding the effects of blue light and social networking on the sleep of young adults. Our previous works have reviewed the effects of short-wavelength light exposure on melatonin expression, circadian rhythms, and sleep patterns (1). In addition, the active use of technology and social networking on young adult sleep patterns has been well documented (2,3). The research on the effects of radiofrequency electromagnetic fields on sleep patterns is quite interesting and novel (4), and further research should be conducted to differentiate the specific effects of blue light and electromagnetic fields on circadian rhythms and sleep patterns. Given that the research is clear that exposure to technology can physiologically and psychologically impact a person’s sleep drive, we provided the standard recommendation that electronics should be avoided an hour before bedtime. Although the physiological effects of cellular phones are noteworthy, the overarching premise of the article “Technology as a Tool to Encourage Young Adult to Sleep and Eat Healthy” was to use technology in a way that enhances self-awareness of patterns of health and wellness. Because many young adults have difficulty placing boundaries on technology use, standard behavioral health recommendations, such as turning off the phone an hour before bed, tend to be difficult to achieve. Therefore, using apps such as SleepBot may work toward maximizing sleep duration, efficiency, and self-awareness of sleep patterns. It should be noted that if SleepBot is used to track sleep, individuals would benefit from using the built-in dimming feature to dim the screen display, using the blue light filter currently built into many smartphones, or turning the screen face down on the surface to minimize exposure to light. These steps would help to minimize the negative effects of blue light on sleep. It seems that the only strategy to minimize exposure to electromagnetic fields would be to turn off the phone, but as mentioned earlier, this is easier said than done in young adults whose need for social inclusion often outweighs the need for optimal sleep health. Sue K. Adams, Ph.D., Department of Human Development and Family Studies, University of Rhode Island, Transition Center, Rm 208, 55 Lower College Rd, Kingston, RI 02881 E-mail: [email protected] Gary Liguori, Ph.D., FACSM, Dean, College of Health Sciences, Co-Director, Academic Health Collaborative, Professor of Kinesiology, 106 Quinn Hall, 55 Lower College Rd, University of Rhode Island, Kingston, RI 02881 E-mail: [email protected] Ingrid E. Lofgren, Ph.D., M.P.H., R.D., Nutrition and Food Sciences, College of Health Sciences, University of Rhode Island, 144B Fogarty Hall, 55 Lower College Rd, Kingston, RI 02881 E-mail: [email protected]

Psychophysical Measurements of Luminance Contrast Sensitivity and Color Discrimination with Transparent and Blue-Light Filter Intraocular Lenses.

IntroductionThe purpose of this study was to measure luminance contrast sensitivity and color vision thresholdfs in normal subjects using a blue light filter lens and transparent intraocular lens material.MethodsMonocular luminance grating contrast sensitivity was measured with Psycho for Windows (version 2.36; Cambridge Research Systems) at 3.0, 6.0, 12.0, 20.0, and 30.0 cycles per degree of visual angle (cpd) in 15 normal subjects (eight female), with a mean age of 21.6 years (SD = 3.8 years). Chromatic discrimination was assessed with the Cambridge colour test (CCT) along the protan, deutan, and tritan color confusion axes. Both tests were performed in a darkened room under two situations: with a transparent lens and with blue light filter lens. Subjective impressions were taken by subjects regarding their visual experience under both conditions.ResultsNo difference was found between the luminance contrast sensitivity measured with transparent and blue light filter. However, 13/15 (87%) of the subjects reported more comfortable vision with the blue filter. In the color vision test, tritan thresholds were significantly higher for the blue filter compared with the transparent filter (p = 0.003). For protan and deutan thresholds no differences were found.ConclusionBlue-yellow color vision is impaired with the blue light filter, and no impairment occurs with the transparent filter. No significant differences in thresholds were found in the luminance contrast sensitivity comparing the blue light and transparent filters. The impact of short wavelength light filtering on intrinsically photosensitive retinal ganglion cells is also discussed.

Spectral radiance of blue light filters on ophthalmic lenses

espanolComo resultado de las mejoras en la tecnologia LED (del ingles, light-emitting diode), las pantallas de la mayoria de dispositivos electronicos actuales estan iluminadas por LEDs. Muchas son las ventajas de esta fuente de luz sobre las fuentes predecesoras; sin embargo, algunas investigaciones recientes han puesto de manifiesto el hecho que la exposicion prolongada a la emision en la zona azul del espectro de los LEDs blancos puede tener un efecto negativo en la salud visual y en los ritmos biologicos (ritmos circadianos). Como consecuencia de ello, los fabricantes de lentes oftalmicas han introducido recientemente en el mercado lentes innovadoras que incorporan filtros de luz azul, especialmente disenadas para los usuarios de dispositivos electronicos. En este trabajo, se evaluaron y compararon diferentes filtros de luz azul en lentes oftalmicas comerciales. Se disponian las lentes frente a una tableta retro-iluminada con LEDs, de manera similar a como un usuario se situaria delante del dispositivo electronico para leer un texto. Se analizo la capacidad de absorcion de varias muestras de un mismo fabricante, y se comparo el resultado entre filtros azules de distintas marcas comerciales. EnglishAs a result of the recent improvement in light-emitting diode (LED) technology, the displays of the vast majority of electronic devices are now illuminated by LEDs. There are several advantages of this type of light source over its predecessors; however, recent research is giving support to the fact that prolonged exposition to the white LEDs emission in the blue spectrum may have a negative impact on visual health, as well as, on biological rhythms (circadian rhythms). As a consequence, ophthalmic lens manufacturers have recently introduced in the market innovative lenses that incorporate blue light filters, especially designed for electronic device users. In this work, the performance of different blue light filters present on commercially available ophthalmic lenses was tested and compared. Lenses were placed in front of a LED-based backlight tablet, in a similar way a common user would be reading a text on the electronic device. The absorption characteristics of the various samples from four different ophthalmic lens manufacturers were measured. Analysis of the different samples from the same manufacturer was conducted and blue light filters from different manufacturers were compared.

Lens study: Taking the strain

Chris Ang, Professor Dejan Dinevski, Dr Natalia Vlasak and Andria Kok evaluate the efficiency of spectacle lenses with accommodative support and a blue light filter in reducing computer vision syndrome/digital eye strain symptoms in comparison with habitual spectacles.

Blue-Light Filtering Spectacle Lenses: Optical and Clinical Performances.

PurposesTo evaluate the optical performance of blue-light filtering spectacle lenses and investigate whether a reduction in blue light transmission affects visual performance and sleep quality.MethodsExperiment 1: The relative changes in phototoxicity, scotopic sensitivity, and melatonin suppression of five blue-light filtering plano spectacle lenses were calculated based on their spectral transmittances measured by a spectrophotometer. Experiment 2: A pseudo-randomized controlled study was conducted to evaluate the clinical performance of two blue-light filtering spectacle lenses (BF: blue-filtering anti-reflection coating; BT: brown-tinted) with a regular clear lens (AR) serving as a control. A total of eighty computer users were recruited from two age cohorts (young adults: 18–30 yrs, middle-aged adults: 40–55 yrs). Contrast sensitivity under standard and glare conditions, and colour discrimination were measured using standard clinical tests. After one month of lens wear, subjective ratings of lens performance were collected by questionnaire.ResultsAll tested blue-light filtering spectacle lenses theoretically reduced the calculated phototoxicity by 10.6% to 23.6%. Although use of the blue-light filters also decreased scotopic sensitivity by 2.4% to 9.6%, and melatonin suppression by 5.8% to 15.0%, over 70% of the participants could not detect these optical changes. Our clinical tests revealed no significant decrease in contrast sensitivity either with (95% confidence intervals [CI]: AR–BT [–0.05, 0.05]; AR–BF [–0.05, 0.06]; BT–BF [–0.06, 0.06]) or without glare (95% CI: AR–BT [–0.01, 0.03]; AR–BF [–0.01, 0.03]; BT–BF [–0.02, 0.02]) and colour discrimination (95% CI: AR–BT [–9.07, 1.02]; AR–BF [–7.06, 4.46]; BT–BF [–3.12, 8.57]).ConclusionBlue-light filtering spectacle lenses can partially filter high-energy short-wavelength light without substantially degrading visual performance and sleep quality. These lenses may serve as a supplementary option for protecting the retina from potential blue-light hazard.Trial RegistrationClinicalTrials.gov NCT02821403