does lcd screen harm eyes made in china

Chemicals leaking from millions of computer screens in homes, offices and schools could damage human health, according to research by Chinese scientists.

Chemistry professor Su Guanyong and colleagues at Nanjing University of Science and Technology in eastern Jiangsu province studied more than 360 types of chemicals used in computer and mobile phone screens and found that 87 of them could be a danger if they got into the environment.

Some chemicals in liquid crystal displays (LCDs) could alter genes, they said. Animal cells mutated unexpectedly if exposed, and preliminary results of their ongoing study published in Proceedings of the National Academy of Sciences on Monday showed that one of the most polluted places was the home.

Researchers said about a quarter of the chemicals from screens they tested might be pollutants. Photo: Getty alt=Researchers said about a quarter of the chemicals from screens they tested might be pollutants. Photo: Getty

Studies found that excessive radiation from screens could speed up the ageing of skin and blue light from diodes could harm the retina of the eye. "But nobody has looked beyond the brightness to unveil the dark secrets behind," Su said.

Over the years, screen panel manufacturers have pushed LCD technology to higher resolutions and faster refreshing rates, but the chemical composition of the liquid crystal that fills their screens has hardly changed.

Su and colleagues produced a list of chemicals used by manufacturers and found that 87 " about a quarter of the substances tested " might be "persisting organic pollutants" that were not only harmful to health, but their composition meant they would take years or sometimes decades to decompose. The exact effect of these chemicals was unknown.

Smartphones mean booming demand for components such as screens. Photo: Ben Sin alt=Smartphones mean booming demand for components such as screens. Photo: Ben Sin

They exposed embryonic chicken cells to liquid crystal taken from the screens and compared them to cells grown in normal conditions. They found genetic changes that suggested the exposed cells had mutated.

The Nanjing team was baffled by the amount of liquid crystal in the air. They knew screens were made in dust-free factories and sealed, but their surveys of hotels, school buildings, canteens, dormitories, electronic product repair centres, homes and laboratories revealed surprising results.

Scientists say cracked screens and leaking chemicals are a worldwide problem. Photo: Shutterstock alt=Scientists say cracked screens and leaking chemicals are a worldwide problem. Photo: Shutterstock

The lowest levels were found in a canteen, a dormitory and classrooms. Su said they were not sure where the drifting liquid crystals came from. Some screens might have been cracked or broken, he said. If a screen was left on for a long time, heat and radiation might cause liquid crystal to evaporate.

"Electric device recycling plants could be a major source of emissions, with broken screens dumped everywhere and little protection. This practice must stop," he said.

As we all know, AMOLED screen is a screen made of self-luminous organic materials. It does not require LCD backlight. When current passes through organic materials, pixels will emit light by themselves. Therefore, compared to LCD screens, AMOLED has more Pure black, higher contrast and other display advantages.

LCD screens rely on LED backlight panels to emit light. Therefore, in the field of smart phones, LCD screens mostly use DC dimming. This is a technology that directly adjusts the brightness of the two sides of the light-emitting component to adjust the brightness. The smaller the current, the lower the brightness.

DC dimming is relatively straightforward, but it also has a big disadvantage. Due to the different wavelengths of the three primary colors, DC dimming can cause unavoidable color casts under extremely low brightness conditions, such as early LCD displays with DC dimming , At low brightness, there will be obvious problems of discoloration.

The DC dimming does not seem to be suitable for AMOLED screens. AMOLED screen is a technology that relies on organic materials to emit light. The display quality is greatly related to the material, and the color difference between pixels will be very obvious.

Unlike DC dimming, which directly adjusts the current to control brightness, PWM dimming is more clever. Everyone knows that switching the light source will cause flicker. The faster the switching speed, the faster the flicker. When the frequency of switching the light source exceeds the limit of the human eye, the brightness of all pictures is superimposed in the human eye, so the frequency will affect the brightness of the screen. This technique is called PWM dimming (pulse width modulation).

However, with PWM dimming, even if the human eye cannot sense the picture change during the switching process, we will respond to this phenomenon. It is more likely to cause fatigue on the muscles on both sides of the eyes, thereby stimulating the refraction system to accelerate vision Ageing.

At present, Samsung ’s AMOLED screens use 250Hz low-frequency PWM dimming technology. When the screen brightness is lower, the possibility that the human eye can perceive becomes larger, and it is more likely to affect sensitive people.

AMOLED displays that use PWM low-frequency dimming for a long time do seem to affect vision, but do n’t think that LCD can survive. Even with DC dimming, it also has an irreversible effect on vision-cannot be ignored Blu-ray hazard.

Different from the AMOLED self-emission mode, the LCD screen uses a combination of backlight and filter imaging. In mainstream technology, many LCD screens will use blue LED backlight panels, which are covered with red, green and colorless three. This kind of filter forms three primary colors of RGB when blue light passes through these three filters.

Among them, the short-wave blue light emitted by the blue backlight board can cause harm to human eyes. Because short-wave light has a greater capacity density and is more penetrating, it will directly penetrate the lens to the retina, causing atrophy or death of retinal pigment epithelium cells.

From a technical point of view, whether it is an LCD or an AMOLED screen, the impact on vision is universal. As far as smartphones are concerned, it cannot be said that AMOLED screens are more eye-damaging than LCD screens.

Even if the LCD party held high the banner that PWM low-frequency dimming is harmful, it could not fully prove that AMOLED screens have an impact on vision, because everyone"s habits of using mobile phones are different, and the impact on everyone is different. There is no doubt that in the end, it is still the habits that need attention. For example, users should try to avoid watching the phone screen for a long time; reduce the viewing time of LCD and AMOLED low brightness in the dark environment.

JIANGSU (China) — Chemicals leaking from millions of computer screens in homes, offices and schools could damage human health, according to research by Chinese scientists.

Chemistry professor Su Guanyong and colleagues at Nanjing University of Science and Technology in eastern Jiangsu province studied more than 360 types of chemicals used in computer and mobile phone screens and found that 87 of them could be a danger if they got into the environment.

Some chemicals in liquid crystal displays (LCDs) could alter genes, they said. Animal cells mutated unexpectedly if exposed, and preliminary results of their ongoing study published in Proceedings of the National Academy of Sciences on Monday (Dec 9) showed that one of the most polluted places was the home.

Dr Su, professor at the school of environmental and biological engineering, said he had been worried about the effect of exposure to computer screens on human health for a long time.

Studies found that excessive radiation from screens could speed up the ageing of skin and blue light from diodes could harm the retina of the eye. “But nobody has looked beyond the brightness to unveil the dark secrets behind,” Dr Su said.

Over the years, screen panel manufacturers have pushed LCD technology to higher resolutions and faster refreshing rates, but the chemical composition of the liquid crystal that fills their screens has hardly changed.

Dr Su and colleagues produced a list of chemicals used by manufacturers and found that 87 – about a quarter of the substances tested – might be “persisting organic pollutants” that were not only harmful to health, but their composition meant they would take years or sometimes decades to decompose.

Dr Su’s team went to a phone repair shop and bought used screens found in six mobile phone brands in China and abroad. “We don’t want to name them because this is not a problem of specific manufacturers. It is the whole industry,” he said.

They exposed embryonic chicken cells to liquid crystal taken from the screens and compared them to cells grown in normal conditions. They found genetic changes that suggested the exposed cells had mutated.

The Nanjing team was baffled by the amount of liquid crystal in the air. They knew screens were made in dust-free factories and sealed, but their surveys of hotels, school buildings, canteens, dormitories, electronic product repair centres, homes and laboratories revealed surprising results.

Liquid crystal was not only present in the air in all of these places, but the second-highest concentration was found in flats, while a laboratory that housed a large number screens topped the list.

The lowest levels were found in a canteen, a dormitory and classrooms. Dr Su said they were not sure where the drifting liquid crystals came from. Some screens might have been cracked or broken, he said. If a screen was left on for a long time, heat and radiation might cause liquid crystal to evaporate.

“Electric device recycling plants could be a major source of emissions, with broken screens dumped everywhere and little protection. This practice must stop,” he said. SOUTH CHINA MORNING POST

The issue of eye health has once again attracted public attention after Changzhi, a city in Shanxi province, announced that they will include the results of the naked eye vision test in the senior high school entrance exam in 2022. According to statistics, the proportion of myopia is 45.7% in primary school students, 74.4%in junior middle school students, and 83.3% in senior high school students. Many parents only regard eyes reading time as the key means to protect their children’s vision, which is not a proper method.

According to the China Children’s Development Report(2019)–Children’s Life Outside School, children spend an average of 43.24 minutes per day using electronic devices on school days and 96.27 minutes on weekends. In middle school, the time spending on electronic devices jumps to the second ranking. Electronic devices have become an important tool for learning, further adults are inseparable from the display screen. If you cannot avoid the using electronic products, choose the right screen to protect the health of your eyes.

LCD blue light is considered to be the most crucial influence on hurting our eye health. The mobile phones, tablets, laptops and so many electronic devices we are using in daily life are all with LED backlight, blue light, with large amounts of high energy to penetrate the lens to the retina, leading to retinal pigment epithelial cells die, the light-sensitive cells lack nutrients, thus causing irreversible damage eyesight.

Moreover, children’s visual system is not physically mature, and the lens absorbs less high-energy visible blue light than adults, so blue light causes more harmful to children.

In addition, the brightness and strobe of liquid crystal display will cause different degrees of damage to people’s eye health. If the light source on the screen is too bright, it may cause glare and even temporary visual impairment in severe cases, so the optimal brightness of the display should be similar to the ambient light.

Strobing is also the problem of liquid crystal display, the dynamic image is consisting of a frame by a frame of static image constantly refresh, the screen has been flashing all the time, but the frequency is too high to distinguish by our eyes, frequent flashing will stimulate the retina, cause eye fatigue, and even dizziness.

E-paper displays have a different luminous mechanism from liquid crystal displays, which can protect our eye health better. E-paper display is a kind of light reflex display technology, also known as the reflective display, it does not have any back light, environmental light can illuminate the electronic paper display and refract light to our eyes, the display effect is as same as paper. This creates comfortable, downy reading environment for our eyes, eyes burden also can be relieved.

Not only that,the electronic paper display as screen is based on the electrophoresis technology,the display effect,after the picture form stable display,all particles won’t move again,even if the power cuts,images will not disappear,so the electronic paper display screen will not appear flashing to stimulate retinal damage,this also is to use electronic paper display products when the eye is not easy to get tired.

E-paper display, with its unique characteristics of bistable reflective technology, paper-like feeling, ultra-wide viewing Angle, thinness, and energy-saving, has become the best display screen for eye health protection. It has been widely used in many fields such as e-readers, electronic schoolbags, and other IoT products.

If a growing body of scientific evidence is to be believed, the LCD screen may be one your health"s worst enemies, capable of causing eye strain, headaches, and sleepless nights.

If you think about it, this makes perfect sense. Through the vast majority of human existence, our species wasn"t staring at LCD screens for hours on end. In a nutshell, our bodies and brains simply weren"t built to handle it. The problem: Many researchers now believe that when you stare at a bright screen, it effectively tricks your body into thinking it"s daytime, making it more difficult to sleep, and resulting in a host of other problems. To make matters worse: Pretty much all of us are regularly looking at their phones, tablets, and computers in bed, when we should be preparing to hunker down for the night.

One company that"s trying to do something about this issue: Gunnar Optiks, makers of so-called "computer eyewear" that"s designed to mitigate the effects of staring at a screen. When Gunnar first launched a few years back, I was a skeptic of their claims. But in the years since, I"ve become more interested in the topic, spoken to more scientists, and now genuinely feel that they are onto something. To delve deep into the science, I spoke with Gunnar Optiks CTO and co-founder Joe Croft about the science of screens, and what his company is doing about them—short of making you give up all your gadgets for good. (Warning, technical talk ahead!)

There is a lot of new research about the effects of LCD lights on melatonin production and its effects on sleep. A lot of people also use computers, tablets, and phones at night or even in bed. Do you view this as a greater offender to health than staring at a computer during the day?

Why focus efforts on glasses? Do you see a time in which companies such as yours would expand into building filters into computer screens that would accomplish the same end result, but perhaps be more adjustable/tunable depending on your particular needs?Glasses are the only method that serves as a complete solution to Computer Vision Syndrome. A computer screen filter would help with a few issues, but not all. The main issues are the following.

2. Near Point Stress Syndrome. Eye muscles have to stay in a continual state of flexion to focus on computer screens. Glasses can relieve the eye strain by taking some of the focusing load.

3. Quality of Light. Screen filters can help here, but glasses are more effective because they work for not only screen light, but for overhead office lighting as well. Overhead flourescent lights are notorious for creating eye strain. High in HEV, very spiky in terms of spectral transmission. The furthest thing from natural full spectrum light that our visual system is designed to see.

4. Glare/Visual Noise. Screen protectors can help here as well. With proper computer eyewear, however you can eliminate reflections that plague many prescription eyewear wearers. They see the reflection off their cornea on the back side of their glasses. Gunnar eyewear specifically targets all types of glare and reflections.

Have there been any challenges in getting the medical community to accept computer glasses as a category?Within the optical community it has been easy. Eye doctors understand all the principles well and it doesn"t take much explaining. Why they don"t like is the over the counter approach. They much prefer to participate in our custom prescription program.

If you want to show these things help one’s health, how do you test that? If you’re seeing noticeable improvements, how long does it usually take for them to show in users?The first step is to establish a baseline. In our study from 2009 we had all the test subjects (over 100) undergo a CVS (Computer Vision Syndrome) symptom evaluation. This became the baseline for whether we saw an increase, decrease, or no-change with the use of Gunnars. After the multi-week study they underwent the same CVS symptom evaluation and for each symptom (ie headache, dry eye, external eyestrain, internal eyestrain, etc etc) we measured the difference. The results were overwhelmingly positive. Our current study is looking at the increases in productivity due to wearing Gunnars. Most wearers notice a difference right when the put them on, but after a multiweek trial, they are hooked.

Since LCD screens likely suppress melatonin, and keep you awake, would it make sense that in situations when you want to stay more alert, that you’d actually want unfiltered exposure to LCD lights?Sure. Same way that taking a No-Doz every once in a while can help you out. Take enough No-Doz on a continual basis and you"re sure to have problems, though! Seriously, though, it"s good to see that there are positive effects of photo therapy. Especially for people in northern geographical locations, it can be very beneficial. The trick is using it in the proper manner and syncing it to your circadian rhythms.

Some research suggests that the melatonin-suppressing effects of LCD light are somewhat specific to blue (and white light lights that contain blue wavelengths), and are not caused by red or orange lights. Do your glasses specifically focus on these offending wavelengths? Any info on how they filter for them?Yes. We have 35% transmission at 450 nm (blue light) and close to 97% once you get into the warmer part of the spectrum.

“I’ve changed to a high-end smartphone with an OLED screen, but my eyes feel uncomfortable.” More and more netizens have this problem. Do OLED screens really hurt our eyes? Recently, a reporter investigated this phenomenon.

“I would never have thought that my eyes were becoming uncomfortable after using a new mobile phone for a few days.” Recently, a netizen reported this issue.

According to the reporter’s investigation, quite a few users have such questions. There are nearly 400,000 related links in Google search for “Eyes hurt by OLED screens“. Many related posts have resonated with netizens because they also had this symptom.

In the past two years, OLED screen smartphones have become the mainstream, and major smartphone manufacturers in the market are applying OLED screens in their flagship models one after another.

The problem is, do OLED screens really hurt our eyes? The reason why you feel uncomfortable when using mobile phones with OLED screens is that they flicker.

LCD screen usually uses LCD backlight to realize screen luminescence, the flickering frequency of which can reach several kilohertz (Hz) that flickering will basically not occur. The pixels for OLED screens are self-luminous, the low power of which has limited its flickering frequency. At present, the flickering frequency of the PWM dimming of OLED screens on many mobile phones is about 215Hz-250Hz.

In the eyes of communication industry professionals, this value is not high. But even the medical circle has not given a clear answer to this question, which is a great controversy in the industry.

Jie Chuanhong is the director of the ophthalmology department of the Eye Hospital of China Academy of Chinese Medical Sciences. He said in an interview that whether you watch the mobile phone screen, computer screen, or iPad screen for a long time, it is easy to cause visual fatigue, which should not be directly related to the screen.

“There is no direct relationship between OLED screen and eye harm.” Communication industry professionals also said that human eyes are almost imperceptible to the flickering of OLED screens. “Visual fatigue may be caused by staring at the screen for too long.”

Some experts claim that both LCD and OLED screens can harm human eyes because they will emit blue light harmful to the eyes, which is inevitable. However, OLED has a way to avoid this problem, enabling the eye-protection mode (similar to PWM dimming) and changing the color tone of the screen to yellowish.

Many netizens also suggested that when using smartphones with OLED screens, we should increase the brightness as much as possible because the lower the brightness, the more harmful it will be to our eyes. When the brightness of the screen is reduced, the screen of the smartphone will further reduce the flickering frequency.

Some ophthalmologists suggest that “human eyes have different perceptions of OLED flickering, and some people are more sensitive. Sensitive users had better use smartphones with LCD screens.” There has not been a unified medical statement about this conclusion.

Some netizens even made a comparison experiment: you can obviously feel that the screen of P30 Pro is not as good as that of Mate20 Pro. This is easy to understand. Different mobile phones may use different screens, and manufacturers such as Samsung, LG, and BOE have different technologies and product quality.

Some experimental results have shown that screen size is not the main factor influencing visual fatigue but the material and physical properties of different electronic screens.

Even for the same mobile phone, whether the screen is good or not depends on “luck”. Because different brands of OLED screens may be used in the same mobile phone model, in many cases, the mobile phone manufacturer will not specify this, nor does it list the screen provider in detail in the user manual.

For example, Mate20 pro screen suppliers include BOE and LG, and some of their products have experienced “green screen” events after being released on the market. According to media reports, all the mobile phones with green screen problems are those with LG screens. That is to say, the screens in the same mobile phone model may be different for the same price. Whether the mobile phone is good or not depends on luck.

This is almost a common problem in the industry. Initially, both the iPhone XS and XS MAX were equipped with Samsung’s OLED screens. But then Apple listed LG as its second iPhone XS screen supplier. In other words, LG screens may be used in the subsequent batches of iPhone XS and XS MAX. Whether consumers buy LG screens or Samsung screens depends on luck.

The color of OELD screens is more vivid, fuller, and realistic. High-end smartphones have been equipped with OLED screens, which have become the mainstream; LCD screens have been used for low-end smartphones, which are no longer the preferred choice.

Why did this happen? “Terminal products such as the ones with fingerprints under the screen and ultra-thin products can only be realized by using OLED screens.” It has become a common recognition in the industry.

Now there is good news BOE suddenly announced that it has successfully developed fingerprint technology under LCD screen, which will be mass-produced by the end of this year.

It is unrealistic for the mobile phone industry to return to LCD screens from OLED screens, and even some people think it means the degeneration of technology. From the perspective of eye health alone, LCD screens will also emit blue light harmful to human eyes. If we really want to protect our eyes, we must reduce the time consumed by smartphones.

47% of U.S. consumers admitted to being unable to last a day without their mobile devices in a 2014 study done by the Bank of America, demonstrating the increasing prevalence of mobile devices. Mobile devices use LCD screens which emit blue light and thus negatively affects not only vision but also overall health. Continual extended screen time mainly can impact your eyes in two major ways.

Digital Eye StrainWhen we look at a screen, our blink rate drops significantly, thus causing digital eye strain. Signs of digital eye strain include slightly blurry vision after using LCD screens for prolonged periods, headaches, dry or tired eyes.

Though digital eye strain is temporary, if left unaddressed, it can turn into a chronic problem.The easiest way to address digital eye strain is to blink more as blinking helps to keep eyes lubricated. Alternatively, try using the “20-20-20 Rule”. Every 20 minutes, stare at something at least 20 feet away for at least 20 seconds. This exercise engages your distance vision and allows the eyes to rest.

Blue Light ExposureBlue light is the highest energy wavelength of visible light. This energy is able to penetrate all the way to the back of the eye, through the eyes’ natural filters. The rapidly increasing amount of blue light exposure that we get each day through digital device use is causing permanent damage to our eyes. The effects of blue light are cumulative and can lead to eye diseases like macular degeneration.

Children are especially at risk due to their developing eyes. Protective pigments which help filter out some of this harmful blue light are not yet present. The risk is worsened further due to their increased exposure to LCD screens.

Try minimising usage of LCD screens by reading print media or using E Ink displays instead. The InkCase, for example, allows users to read for prolonged periods with minimal power consumption by adding a secondary E Ink screen on the back of your phone.

see the light flickering at a very high frequency, thestroboscopicdoes exist. If thestroboscopicfrequency is very low, it can be easily observed by human eyes.

Some people are hooked to watching show after show, putting their eyes at risk. But screen type is not the only factor in eye-healthy screen time. It really depends on the TV brightness, room lighting, distance from the screen, and view time. How? Let’s break it down:

The closer you go to the television, the more your eyes begin to strain. For both kids and adults, it is not necessary nor healthy to sit close to the screen. The basic rule is to sit at least five times as far away from the screen as it is wide. So, if your television is 32 inches wide, for example, the ideal viewing distance is 160 inches or around 13 feet.

The recommended viewing distance for televisions with 4K resolution is one and a half times the screen size. The recommended distance for HDTVs is three times the screen size of the TV. These guidelines also go for children, who may be the biggest culprits in non-safe viewing practices. If you must, rearrange your living room to space out the good seats away from the TV.

How does that translate into TV screen types? And what screen type should people use to better protect their eyes when watching various shows on television?

The most common display technologies are LED and LCD. The latest TV display technology is OLED, which is only available on high-end TVs. The pixels used to provide the display are the difference between LCD, LED, and OLED. When compared to LED backlight, OLED has a far higher resolution and delivers cleaner, better graphics.

An OLED (Organic Light-Emitting Diodes) screen consists of numerous pixels that emit its own light. Each pixel is made up of three separate RBG – red, blue, and green – OLEDs. OLEDs are true emissive components that produce light on their own and do not require a light source. Meaning they produce a light that’s more natural and less harsh on your eyes.

OLED TVs also provide excellent color and contrast because they do not use light from other sources to display colors, as LCD/LED TVs do. They also, on average, produce around 20% less blue light than LCD displays.

Both LCD and LED TVs work in similar ways to each other. The only difference between the two is the type of backlighting. A TV labeled as an LED utilizes LED illumination for the white backlighting instead of fluorescent (CFL) lamps.

While LED LCD TVs are more appealing than CFL LCDs, they cannot compete with OLED panels since the LCD/LED front panel is a liquid color display that is not self-emissive. Which is the biggest disadvantage of LCD/LEDs in terms of eyesight. Although they produce quality images, the color and contrast from these displays are due to their light sources, so they give off more brightness that can cause eye strain if not moderated.

To sum it up, OLED displays are better for your eyesight. They have more natural lighting, better color contrast, and a wider color range. However, no matter what type of display you have, you will hurt your eyesight if you don’t practice safe TV viewing.

When you turn on most digital devices, their screens vibrantly illuminate so that you can see easily in a variety of light settings. However, the visible light that comes from your screen is more complex than you might think.

While we tend to only think of blue light coming from display screens, it’s naturally produced by the sun. Even indoors, fluorescent and LED light bulbs are sources of blue light.

Whether you’re aware or not, you’re surrounded by blue light all of the time. Most computer monitors, cell phone screens, and flat-screen TVs are additional sources of blue light. This is because white light LED combines with blue LED to create a solid-state light which uses significantly less energy and power than alternative sources of light, making it ideal for electronic devices.

Blue light is harmful the same way having too much sodium in our diet is harmful. Our bodies are naturally adept at absorbing and dealing with blue light exposure, but like anything else, too much can be detrimental.

But is blue light harmful to the eye? While our skin doesn’t have much of a problem absorbing and dealing with blue light, our eyes don’t have the same level of protection or filtration.

One of the most common side effects of blue light exposure is digital eye strain. If you stare at a computer screen for too long, you may start to experience pain in your eyes and headaches.

Digital eye strain, also known as computer vision syndrome, may lead to dry, sore, red eyes and blurred vision. With enough prolonged exposure, blue light can harm your eyes and lead to macular degeneration - causing damage the same way UV rays would.

The same study also found that green light may be damaging and strenuous on the eyes as well. The typical wavelength of blue light falls between 450 and 490 nanometers. The wavelength for green light is 520 to 560 nanometers, with cyan falling in between.

Because the two lights are so similar in terms of strength, and there are few remedies for green light exposure, it’s important to limit and monitor the amount of screen time you’re getting from computers and devices each day - even if you use a blue light filter.

It’s not just blue light that can affect your vision. As we age, the lens inside our eye can lose flexibility, resulting in the inability to change focus from far to near. Getting regular comprehensive eye exams are an important component to maintaining eye health, no matter how much time you spend in front of screens.

Dry eyes are irritated eyes. Your body’s natural defense is to blink. This lubricates and cleans our eyes, and in normal situations the average person blinks 10 to 20 times per minute. Unfortunately, studies have shown that when we concentrate, our blink rate drops. We only blink 3 to 8 times per minute when reading, watching TV, or looking at a computer screen [2].

Take time to rest your eyes every 20 minutes or so. Look away from the computer and focus on something distant - like a poster on the wall across the room or out a window. Close your eyes gently, then squeeze and hold them shut for a moment, then open and relax them. Try to remember to blink more often in between, too, and when you are thinking, instead of squinting at the screen, turn away and blink a few times. Your eyes will thank you.

Built-in nighttime settings on devices often leave an orange tint on the screen that can distort images and diminish the quality of your viewing experience if you’re watching a video or surfing the web. However, they are effective at reducing your exposure and protecting your eyesight.

One of the most popular blue light filter applications is F.lux®. Like most blue light filter applications, F.lux reduces the blue light coming from your screen and boosts the warmer colors like red, yellow, and orange. One of the unique features that makes F.lux stand out from the other applications is the ability to adjust your settings to the time of day. Rather than setting timers and remembering to activate the filter on your PC or device, F.lux will automatically change in accordance to the ambient light throughout the day.

Video and movie displays are often the most affected and distorted by application-based blue light filters. Fortunately, the video setting on this blue light filter is one of the best. You won’t get an ugly orange glare from your screen when you’re watching movies late at night on your laptop or PC.

With Night Light you can set a timer that controls the lighting on your computer screen for a section of time; for example, sunset to sunrise. What’s great about Night Light is the ability to control how much your screen’s blue light decreases.

From sore eyes and blurred vision to headaches, doctors have a catch-all term for any screen-induced discomfort: “Computer vision syndrome,” says Dr. Joshua Dunaief, an ophthalmologist and macular degeneration researcher at the University of Pennsylvania. Dunaief says the specific causes of computer vision syndrome (CVS) are numerous, from improper reading glasses to an overly bright screen. But in most cases, any eye issues you’re experiencing stem from two root issues. Either your eyes are dried out, or they’ve become too fatigued to see properly.

“There are tiny muscles inside your eyeball that change the shape of your eye’s lens in order to bring whatever you’re seeing into focus,” Dunaief explains. After hours of sitting in front of your computer screen, those muscles can grow tired from focusing on a single fixed point. “In some cases, those muscles become so fatigued that your eyes can no longer focus,” Dunaief adds. He says research has also shown that when reading or working online, people tend to blink less. That can lead to dry eyes, tearing, or a burning sensation, he says.

While you’re not powerless to combat these problems (more on that in a minute), Dunaief says these issues are typically short-lived—meaning they go away within a few hours if you abandon your computer. But are there any serious, long-term dangers associated with digital screens?

“Possibly,” Dunaief says. “There’s evidence that bright light can damage your retinas irreversibly. That might mean staring at a computer screen that is very bright could damage your eyes.” He says there’s also some experimental evidence indicating regular exposure to computer-strength light could be damaging in similar ways.

Sitting too close to your computer screen (or holding your cell phone very near to your face) could also potentially lead to some vision problems, explains Dr. Joan Portello, an associate professor and researcher at the State University of New York School of Optometry. “A lot of people don’t realize this, but when you’re viewing something really close, that’s when your eyes are working the hardest—much harder than when you’re looking at something far away,” Portello explains.

Both she and Dunaief say there’s some evidence that students who spend many hours hunched over textbooks tend to become nearsighted. (Some Chinese schools have started employing metal desk bars to keep kids from lowering their heads too near to their study materials.) “Kids who play outside a lot tend to have better distance vision,” Portello adds. “And heavy computer use could turn out to cause some similar issues to this close textbook reading.” Like Dunaief, Portello says it’s too early to say how bad long-term computer use is for your eyes.

One thing is crystal clear: Computers aren’t going anywhere. So what can you do to safeguard your sight? First and foremost, proper eyewear is essential—especially if you’re older than 40, when reading small print tends to become troublesome for most people, Dunaief says. “Your reading glasses aren’t made for your computer,” he explains. Ditto for your regular spectacles. “An optometrist can fit you for glasses made specifically for computer use that will make things easier on your eyes.”

Dunaief also recommends dimming your computer screen and moving it as far away from your eyes as comfort and readability allow. Enlarging the font, closing blinds, and turning down the lights in your office to prevent glare can also help keep your eyes safe, he explains.

Portello says eye drops or artificial tears can help, as long as you consult with your eye doctor first about which type will work best for you. She also recommends sticking to the 20-20-20 rule. “Every 20 minutes, look away from your screen at something 20 feet away for 20 seconds,” she advises. Why? This gives your eye muscles a rest and helps ward off fatigue and strain. Focusing on something even farther away is just as good, she adds. “And while you’re at it, try to blink as much as you can to keep your eyes moist.”

In the modern world, our eyes are constantly bombarded with information from displays. Whether it be from a laptop, smartphone, or some other device, many of us spend a significant portion of our day staring at some kind of display. As such, it is paramount that we should understand the strain placed on our vision and some steps we can take to improve and protect the health of our eyes.

Our eyes are constantly fed information through screens. Most of us have jobs that require us to look at a computer display of some kind for several hours a day. After work, we head home and stare at screens throughout the evening and well into the night. It"s no wonder, then, that many people complain of eye strain, blurred vision, or headaches after a long day of work. These symptoms and others, collectively known as computer vision syndrome (CVS), may affect as many as 90% of people who use a computer monitor, tablet, or other electronic display during the workday.

So what can we do about CVS? There"s no escaping the fact that many jobs require computers and, thus, require staring at a screen. In this article, we will discuss a few things you can do to reduce eye strain and alleviate some symptoms of CVS. We will also offer a list of laptop features that may adversely affect our eyes and what facets of notebooks may lighten the ocular load. Finally, we will offer a short list of some recommended laptops with high-quality screens that have some of these vision-saving features.

The good news is that there are several steps you can take to minimize or outright prevent symptoms of CVS. Our eyes work like biological cameras; they are constantly focusing on an image, taking in light, and transmitting visual data to our brain for interpretation. By understanding how our eyes look at electronic displays, we can better control the stress placed upon them. The following list is by no means exhaustive, but these tips should help you if you consistently suffer from headaches, blurry vision, eye strain, or other common problems associated with CVS. Best of all, these are simple solutions that shouldn"t require you to buy new equipment or change your working situation.

Refocus your eyes periodically. Perhaps the best way to protect your vision is to give your eyes a break. If you spend an extended period of time in front of a computer monitor or other display, look away from the screen every 20-30 minutes. Pick out a distant object or spot on a faraway wall and focus on it for about 30 seconds. This refocusing removes the immediate strain placed on your eyes, and focusing on a distant object will help relax the muscles that control your eye.

Blink often. Blinking coats our eyes with tears and helps clear out any dust or particles that have found their way past our eyelashes. While blinking is an automatic reflex, some studies show that blinking rate is significantly reduced when we actively process information, such as when we are working at a computer monitor. This can lead to our eyes feeling dried out and may damage them over time. Like above, take a break every 20-30 minutes and intentionally blink your eyes very slowly 10 or more times. This will spread new tears over your eyes. You may also want to purchase lubricating eye drops if you suffer from very dry eyes.

Adjust your lighting. Some lighting situations can actively damage our eyes, particularly bright environments. There"s a reason why we squint when we step outdoors on a sunny day; our pupils contract, which requires some muscles in our eyes to stay flexed. If you can, turn down the lights in your office and partially block any ambient light coming in from outdoors. Turning off overhead lights or fluorescent bulbs can also help. Incandescent and halogen bulbs are easier on our eyes, and placing them lower down to offer indirect light can help reduce strain.

Adjust your display"s settings. Most modern LCD monitors and laptop displays allow the user to edit some settings. Lowering the brightness of your computer"s display will reduce ocular stress, similar to turning down ambient lighting. There is a threshold, though; if the computer screen is too dim, it can actually cause worse eye strain. Find a good sweet spot by incrementally stepping down the display"s brightness until your eyes aren"t squinting or straining too much to read text or view images. You can also download software to filter out blue light. Blue light has a shorter wavelength than red light and thus can cause greater eye strain, particularly if viewed at night. Blue-light filtering software shifts the color gradient of your computer"s display toward the red end of the light spectrum, increasing the wavelength of emitted light and reducing stress. A good app for this is f.lux, which can be set to automatically shift your display throughout the day. F.lux is free for personal use and is available for Windows, Mac, Linux, Android, and iOS (jailbreak required).

In addition to the tips listed above, there are some laptop-specific factors that can directly affect our vision. Laptop screens vary widely from model to model, and there is no one perfect laptop screen when it comes to eye health. Still, here are a few things to keep in mind when you purchase your next laptop.

Matte screens are easier on the eyes. Perhaps the most noticeable facet of a laptop"s screen is the finish across the panel. Laptop displays have either a glossy or matte finish to them. Glossy panels allow more light to pass through from the LCD backlight and are typically brighter and more color accurate. However, glossy displays have a major weakness: reflections. A glossy finish will typically show reflections at lower brightness levels, which can distract our eyes and cause them to constantly shift focus, resulting in increased fatigue. Matte finishes, on the other hand, are made specifically to cut reflections. Matte displays typically show no reflections, making them highly usable in almost any lighting condition (provided the backlight is bright enough). Matte screens do sacrifice some color accuracy and brightness, but most are more than good enough for users that don"t routinely work with color.

Higher resolutions make everything sharper. Most modern laptops come with either a 1366x768 or 1920x1080 resolution screen, which is acceptable for most work. However, users that suffer from eye fatigue may want to consider getting a higher resolution display. A higher resolution means a higher pixel density, which can make text and images look much sharper. While a high-resolution screen will make icons and other UI elements smaller at the display"s native resolution, both Windows 10 and Mac OS X have excellent scaling options. Text on a 4K screen set to 200% scaling will look much crisper than text on a 1080p screen at native resolution.

Screen size affects pixel density. Related to point #2 is screen size. Obviously, a smaller laptop screen will subsequently be harder to see from a normal viewing distance than a larger laptop screen. That being said, a larger laptop screen will have a smaller pixel density than a smaller screen of the same resolution. For reference, a 15.6-inch display with a resolution of 1920x1080 has a pixel density of 141 pixels per inch (PPI). Choose a laptop with a screen large enough for comfortable viewing from your desk chair. A larger screen would need a higher resolution to match this pixel density. It should be noted that Apple"s "Retina Display" moniker is a classification used by the company to describe a pixel density high enough such that individual pixels are not visible at a normal viewing distance. The iPhone 4 had the first "Retina Display" with a PPI of 326. Apple"s Retina MacBook Pros typically have a lower pixel density (~220 PPI) but are viewed from farther away than a smartphone.

Backlight brightness matters. While it"s important to control the intensity of light coming out of a laptop screen, making sure that the LCD backlight is bright enough to remain visible is equally as important. A screen with too dim a backlight can be hard to see in some lighting conditions, causing our eyes to strain to view the display. A backlight that can climb to 300-350 nits should be sufficient for most environments.

Poor contrast muddies up the display. Also worth considering is the contrast ratio and black levels of a display. Poor contrast can result in blurry or muddy images with ill-defined boundaries. This can subsequently force our eyes to constantly refocus in order to make sense of the boundaries of an on-screen picture or text. A contrast ratio of 1000:1 or higher will be adequate for most users.

PWM can be a headache. Many laptops rely on pulse-width modulation to dim the LCD backlight. We have written a detailed article on the issue, so suffice it to say that higher PWM causes less strain on the eyes. Laptops with low PWM (<500 Hz) can cause eye fatigue, headaches, and other adverse symptoms in some users. We measure the PWM (or lack thereof) of almost every device that crosses our test bench, so be sure to check a specific laptop review before buying to see if PWM is problematic.

Now that we know what to look for in a laptop, here is a list of some suggested devices that meet most of the criteria listed above. Again, there is not one "perfect" laptop when it comes to eye health. Still, the following devices come close and should help alleviate eye strain. Remember, the best way to protect your eyes is to take action yourself.

The laptop display that ticks the most boxes perhaps belongs to the 14-inch HP EliteBook 840 G5. The FHD panel is reasonably pixel-dense (157 PPI), has a good contrast ratio (1170:1), and is fairly color-accurate. What really sets the EliteBook 840 G5 apart is its backlight, which is one of (if not the) brightest on the market right now. The screen shines at an insane 630 nits on average, and the backlight is very evenly distributed (93%). In addition, the matte finish across the panel eliminates reflections and allows for use in all but the brightest conditions. While the 14-inch display may be too small for comfortable viewing from a distance, the EliteBook 840 G5 offers one of the best displays for eye health on the market today.

The Dell XPS 15 has long been touted as the Windows alternative to Apple"s MacBook Pro line for many reasons, but the display is often one of them. While Dell offers an alternative SKU of the XPS 15 9570, its glossy panel readily shows reflections and is thus not as conducive to eye health as its FHD matte sibling. While PPI could be higher on the FHD panel, the screen is pixel dense enough for most users. What makes the FHD XPS 15 9570 a good choice is its bright and relatively even backlight, its excellent contrast ratio, and matte finish. PWM is high enough that it will not bother most users, although some very sensitive eyes may be affected. Despite these small compromises, the FHD XPS 9570 is perhaps the best balanced display when it comes to eye health.

For those that want a larger screen, it"s hard to beat the 4K Lenovo ThinkPad P71. The 17.3-inch display is large enough to be easily viewed from a normal working distance, and the 4K resolution packs 255 pixels into every square inch. The 4K P71 offers a good contrast ratio (1155:1), good viewing angles, great color accuracy, and a matte finish. Its main weakness lies in the display backlight, which is somewhat dim (~330 nits) and uneven, making outdoor use more difficult than with the EliteBook 840 G5 or the XPS 15. The P71 is perhaps the best large display and one of the best for eye health.

There"s a reason why Apple"s MacBook Pro devices are often praised for their displays. The panel on the MacBook Pro 15, in particular, is one of the brightest screens in the industry (~520 nits). The pixel-dense (~220 PPI), color-accurate screen has an excellent contrast ratio (1333:1). The device"s "Retina" display can be set to a wide variety of brightness levels for almost any lighting situation and has almost imperceptible PWM (>20,000 Hz). The one flaw in the display is its glossy finish. While the backlight gets bright enough to help reduce reflections in most lighting conditions, bright days outdoors turn the screen into a mirror, which can be highly distracting and fatiguing. If you rarely or never work outdoors or under bright lights, though, the MacBook Pro 15 should offer easy viewing.

Our eyes are one of our greatest resources, and keeping them healthy is important. As our lives focus more and more on electronic displays, the task of protecting our vision becomes increasingly difficult. Still, there are some laptop displays that are noticeably easier on the eyes than others. That being said, the most important thing to remember when it comes to keeping your eyes healthy is to take action yourself. Look away from your screen periodically and give your eyes a rest. This is the best way to ensure your eyes keeping looking good (pun intended) for years to come.

Polarized sunglasses may make it easier and more comfortable to see outdoors, but wearing them while trying to read an LCD (liquid-crystal display) screen can sometimes — literally — leave your eyes in the dark.

Most LCDs, such as your smartphone and tablet, use a polarizing filter to help you see the screen in bright sunlight. But so do polarized sunglasses, meaning the two essentially cancel each other out, causing your LCD screen to appear dark or completely black when you look at it.

LCD screens and sunglasses typically contain a polarizing filter for the same reason: to make it easier for you to see clearly, especially in bright sunlight.

What tends to happen is your polarized sunglasses do their job by only allowing light to pass through vertically. Meanwhile, your phone screen emits horizontally vibrating light while blocking vertical light.

Your lenses and screen end up counteracting each other by working in opposite directions. As a result, you wind up seeing a dark or blacked-out image.

The solution is simple: Rotate your tablet or phone screen by 90 degrees. This trick usually works because it positions your screen’s polarizing filters so they block light waves traveling in the same direction as your polarized sunglasses, allowing light to pass through.

Newer smartphone and computer screens have found ways to compensate for this issue, but you may still notice a darker screen when wearing polarized sunglasses with an older model screen.

In some cases, you may need to view LCDs on an instrument panel that can’t be rotated. This can be true for boaters and pilots who must be able to read instrumentation quickly and accurately to ensure their safety. For this reason, you should avoid wearing polarized sunglasses in these circumstances.

You also can test your sunglasses by looking at an LCD screen while wearing them. Just remember to rotate the device 90 degrees to make sure you’re checking for a polarizing filter that blocks light traveling either horizontally or vertically.

If you’re always surrounded by displays—PCs, smartphones and tablets—are you placing too much strain on your eyes, neck and shoulders? If this sounds like you, read this article and take steps to address it right away before your symptoms worsen.

Information technology has made our lives more convenient, but at the same time, eye fatigue caused by continuous viewing of displays has increasingly become a social problem. If you feel fatigue in your eyes, neck or shoulders, it"s important to properly address it rather than letting it go. If you let it go and your symptoms worsen, you could damage your mental and physical health, so be careful.

Some of the names for the various problems associated with displays and eyes are "computer vision syndrome," "VDT (visual display terminal) syndrome" and "technostress ophthalmopathy." They"re unavoidable problems when it comes to PC work in particular. There are various ways to address the problems, and the effects vary from person to person, but if you try one at a time, you"ll undoubtedly be able to experience a more pleasant digital life. It will also contribute to improved productivity in the office.

Have you ever been on a train and had the sun shine on your book from behind you making it hard to read or on your smartphone screen creating a glare and making it hard to see?

When you"re working on your PC, similar poor conditions may develop without you realizing it. For example, if the lights are near the center of the room, and your PC is set up with you facing the wall, although the level of brightness is different, you could experience something similar to sunlight shining on your screen from behind you like on the train. If that"s the case, consider changing the layout.

What can further worsen your eye fatigue in a situation like this is the light reflected from your display. Shiny glare panels are made to provide accurate blacks and colorful display, so they are good for watching videos, but they also tend to reflect outside light. In an office or similar setting, lights and other displays can be reflected on your screen, throwing off your focus and causing eye fatigue.

For regular PC work, an LCD with a non-glare panel that does not reflect light is easier to use. If the product you"re currently using has a glare panel, you can affix low-reflection film to the screen.

Fluorescent lights are brightly reflected on the glare panel, making the screen hard to see. These conditions can easily strain your eyes (left). A non-glare panel can substantially reduce the reflection of fluorescent lights and reduce the strain on your eyes (right). The difference is as plain as day.

It’s also important not to make the lights in the room too bright. It"s common for advice to focus on not letting the room be too dark, but if the lights are too bright, it creates a difference between the screen brightness and ambient light, and that"s also no good. More specific details on screen brightness are provided in Point 5. Also pay attention to the temperature setting on your air conditioner and the direction in which it blows. These things can cause dry eyes, and your seat should never be positioned so that the air conditioner is blowing directly in your face.

Generally speaking, the distance between the user and the screen should be at least 40 centimeters or 50 centimeters in the case of a wide screen. The reason you should be further away from a wide screen is that the wider screen will not fit completely into your field of vision unless you sit further back. The conditions will vary slightly depending on other factors as well, including screen resolution, text size and your eyesight.

No matter what the situation, if you are viewing a screen at a distance of less than 30 centimeters for long periods of time, your eyes are obviously going to become fatigued. If you have an A4-sized sheet of paper, hold it up longways between you and the screen on which this article is displayed and see if there is enough room for it to fit. An A4-sized sheet of paper is about 30 centimeters (297 millimeters) long, so if you"re viewing the screen from a shorter distance than this, you"re too close. If you"re viewing it at a distance of about 1.5 times that length, you"re safe for now.

Once you"re at the proper distance from the display, try to have it so that your line of sight is directly ahead or slightly downward when viewing the screen. You should avoid looking up at the screen, because that can cause dry eye.

Displays that do not allow sufficient adjustment of the angle and height of the screen can lead users to adjust their posture to the screen position, which prevents them from working in the correct posture. Choose a display that has rich features including a tilt function allowing the screen to be tilted up and down and a height adjustment function.

The adjustment mechanism of the LCD is also important for working on a PC in a posture that does not strain the eyes, neck and shoulders. Choose a product that allows the screen to be lowered just above the table top and flexible tilt adjustments (photograph: EIZO"s FlexScan EV2436W.

Even if the installation location of the display and your posture during use is proper, working in the same posture for extended periods of time is not good for your eyes. The reason is that constantly looking at something at a fixed distance causes a gradual decline in your eyes" ability to focus.

Take a 10-15 minute break at least once an hour. Look into the distance and move your eyes up, down, left and right to adjust your focus. It"s also good to regularly use eye drops.

A common mistake people make is looking at smartphone and tablet displays during their break. This does not allow your eyes to rest. Stretch to relieve tension, stand up and walk around, and look near and far either indoors or outdoors to adjust the focus of your eyes.

The suggestions up to this point have been predicated on the assumption that you have sufficient eyesight or that you use glasses or contact lens to properly correct your eyesight.

Eyesight changes gradually during daily life activities. Even if you wear glasses or contact lenses, if you stay at the same prescription for many years, your eyesight will change without you realizing it, and this could cause eye fatigue or migraine headaches. Using eye drops and adjusting the focus of your eyes during breaks does not help this problem.

Where you get in trouble is your eyesight doesn"t change suddenly one day, so even if you have symptoms like eye fatigue and headaches, it"s hard to identify the cause. If you let it go, it could lead to glaucoma and other worsening symptoms, so you should have your eyes checked at least once a year, which may be included in your company or school health examinations. Be vigilant about checking to make sure your prescription is not off.

The brightness of your display should not be left at the default setting but adjusted according to the brightness of the room where it"s installed. This can greatly reduce the strain on your eyes. For example, in an office with normal brightness of 300-500 lux, the display brightness should be adjusted to around 100-150 cd/m2.

But when you give specific numbers like this, most people have no idea what they mean. So what you want to remember is that the trick to adjusting the brightness is using white paper like copy paper. Compare the paper under the lighting in the room to the screen, and adjust the brightness of the display so that the brightness matches as closely as possible. This will put the brightness at about the right level.

Particularly, when using the display for work, you"ll often be comparing paper documents with documents on the screen, so by adjusting the brightness of the screen to the brightness of the paper under the lighting, you"ll reduce the strain on your eyes, making this an effective measure against eye fatigue.

Put white paper next to the screen as shown, and adjust the display brightness while comparing it to the paper. Screen too bright c