is lcd display good for eyes free sample

The television is one of the most common electronic in any household. Even in the age of digital media, people choose to spend their free time at home with their families watching television.

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:

Whatever type of television you have, it emits light with most TVs emitting at least 50% of blue light. Because blue light is closer to UV rays on the light spectrum, it may have similar qualities to how it affects people. Blue light exposure has long been linked to health issues such as eye damage, vision loss, and insomnia. So, as the brightness of your TV is increases, the color, and contrast of the image decrease, causing eye strain.

Ambient lighting should be present in the room when watching TV. It’s not a good idea to watch TV in complete darkness -- yes we’re talking to you late-night viewers. The room’s brightness should be adequate and comparable to the television. Even in theaters, the lights are never completely off, just dimmed; that same rule should apply to your home.

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.

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.

However, being more "ideal" also means paying more. The "eye-damaging" of AMOLED displays stems from external dissatisfaction with the current widespread adoption of PWM low-frequency dimming by AMOLED manufacturers. Here is a brief explanation of the PWM low frequency dimming technology.

All displays have a brightness adjustment function, but due to the differences in materials, the dimming technology is different. The current mainstream brightness adjustment technologies for smart phones are DC dimming and PWM dimming.

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.

In fact, even though this problem has not been solved very well, maybe it is the case that PWM dimming has become another option and has entered everyone"s sight.

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).

The introduction of PWM dimming solves the problem of low-brightness color cast in the early days of AMOLED displays, and in fact further improves color stability.

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.

“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.

She went to see a doctor and was diagnosed with floaters. The doctor advised her to use her mobile phone less. It is strange that her symptoms were relieved after she changed back to her old mobile phone.

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.

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.

IEEE (Institute of Electrical and Electronics Engineers) once reported that the range of flickering frequency with low health risks is above 1250Hz. “Flickering may lead to migraine and other diseases.”

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.

Are computers bad for your eyes?  And if so, what can be done about it?  These are questions that thousands of Australians ask every week.  The past ten years has seen enormous changes in the use of computer screens.

Once a desktop screen used only at work, the computer screen has been promoted to a mobile device that is with us 24/7.  The latest generation of teens and young adults stare at their smart phones, iPads and games consoles all day.  Coupled with this increased exposure is the increased intensity of light emitted from these screens. Is this harming our eyes?

This is one of those questions that anyone buying a new TV asks but most people are unaware that it’s a misleading question.  Technology manufacturers like to draw an artificial distinction between their LED and LCD monitors.  This cons us into believing that the LCD has been superseded by the LED, when in actual fact all that’s changed is the way the LCD monitor is backlit.

LCD (liquid crystal display) technology – to the uninitiated – involves sandwiching a liquid layer between two layers of glass and backlighting it. Older technologies backlit the screen using fluorescent light – called CCFL (or cold cathode fluorescent light). This produced light across all parts of the spectrum, with the peak in the green light part of the spectrum (see image, left).

More modern computers still use LCD screens but the backlighting used is more often LED (light emitting diode) technology. This has many advantages over the older fluorescent light technology.  It provides a thinner, lighter and more energy efficient display – generating less heat and consuming less power. However, the LED light spectrum is very different to the older fluorescent technology and emits a lot more light from the blue-violet end of the spectrum (see image, right).

UV light is invisible, but its very short wavelengths allow it to penetrate the delicate superficial tissues of our eyes and skin and cause oxidative damage. This is what leads to skin cancers as well as contributing to many eyes diseases particularly of the cornea and lens – i.e. cataract, pinguecula and pterygium.

Blue-violet light is visible light, but is on the part of the spectrum right next to ultra-violet. Blue-violet light has been shown to be toxic to the delicate structures of our eyes. It can penetrate deeper into the eye – as far as the retina – and it is emerging in clinical data that is has a negative effect on the health of our eyes, particularly for age-related macular degeneration.  The mechanism by which blue-violet light damages the retina is still being studied but it is thought to disrupt cellular metabolism at the back of the eye.  Blue blockers are glasses which filter out blue-violet light. The filter can be worn with or without a glasses prescription.

Not all blue light is bad!  At the greener end of the spectrum is blue-turquoise light.  Unlike blue-violet light this kind of blue light is beneficial to us.  This is the light that helps regulate our bio-rhythms, telling our bodies when to wake up in the morning and slow down before sleep. Blue light suppresses melatonin production in our bodies, so it is not healthy to be exposed to artificial blue light late at night as it prevents us our natural winding down mechanism from kicking in. This is a good reason why digital screen use should be avoided in the hours preceding sleep, regardless of whether blue-blockers are worn.

The negative effects of blue light on the eye are especially true for children. We previously wrote about kids’ eyes and computers here. (Link to clock-lock-block article).  The image below shows the relative intensity of light at various wavelengths for a typical L ED screen. It doesn’t matter what the device, if it’s modern, it’s typically emitting most light at the blue end of the spectrum.  This is bad news for our kids, who often spend hours per day on digital devices such as tablets and smartphones.

Take home message?  Exposure to blue-violet light should be limited as much as possible. Companies like BenQ now make all their screens with blue light filtering technology.  Children’s use of digital screens should be limited, to protect their particularly delicate eyes.  For the rest of us, blue blockers can provide protection from harmful blue-violet light but to get a good night’s sleep you should also limit screen exposure before bedtime.  And yes, that means TV too!

This website is using a security service to protect itself from online attacks. The action you just performed triggered the security solution. There are several actions that could trigger this block including submitting a certain word or phrase, a SQL command or malformed data.

If you ended up on this page doing normal allowed operations, please contact our support at support@mdpi.com. Please include what you were doing when this page came up and the Ray ID & Your IP found at the

Blue light has gotten a bad rap, getting blamed for loss of sleep and eye damage. Personal electronic devices emit more blue light than any other color. Blue light has a short wavelength, which means that it is high-energy and can damage the delicate tissues of the eye. It can also pass through the eye to the retina, the collection of neurons that converts light into the signals that are the foundation of sight.

As an assistant professor at The Ohio State University College of Optometry, I teach and conduct vision research, including work with retinal eye cells. I also see patients in the college’s teaching clinics. Often, my patients want to know how they can keep their eyes healthy despite looking at a computer screen all day. They often ask about “blue-blocking” spectacle lenses that they see advertised on the internet.

One way to think about blue light and potential retinal damage is to consider the Sun. Sunlight is mostly blue light. On a sunny afternoon, it’s nearly 100,000 times brighter than your computer screen. Yet, few human studies have found any link between sunlight exposure and the development of age-related macular degeneration, a retinal disease that leads to loss of central vision.

If being outside on a sunny afternoon likely doesn’t damage the human retina, then neither can your dim-by-comparison tablet. A theoretical study recently reached the same conclusion.

Human eyes are different than rodent eyes. We have protective elements, such as macular pigments and the natural blue-blocking ability of the crystalline lens. These structures absorb blue light before it reaches the delicate retina.

That doesn’t mean you should throw away those sunglasses; they provide benefits beyond protecting your eyes from the Sun’s blue light. For example, wearing sunglasses slows down the development of cataracts, which cloud vision.

Just because blue light isn’t harming your retina doesn’t mean your electronic devices are harmless, or that blue light doesn’t affect your eyes. Because of its wavelength, blue light does disrupt healthy sleep physiology. Blue-light-sensitive cells, known as known as intrinsically photosensitive retinal ganglion cells, or ipRGCs, play a key role here, because they tell the brain’s master clock how light it is in the environment. That means, when you look at a brightly lit screen, these cells help set your internal clock for daytime-level alertness.

As for your tired eyes after a long day spent staring at your computer – another common complaint I hear from my patients – blue light isn’t solely to blame for that, either. A recent study demonstrated that cutting blue light alone did not improve people’s reported comfort after a long computer session any more than simply dimming the screen.

Many patients want to know if they should buy certain products they have seen advertised to block out blue light. Based on research, the short answer is “no.”

Mounting evidence suggests that, compared to reading a paperback, screen time before bed increases the time it takes to fall asleep. It also robs you of restorative rapid-eye-movement sleep, dulls focus and diminishes brain activity the next day. Holding your phone close to your eyes with the lights on likely exacerbates the problem.

Second, the products that my patients ask about do not block out much blue light. The leading blue-blocking anti-reflective coating, for example, blocks only about 15% of the blue light that screens emit.

You could get the same reduction just by holding your phone another inch from your face. Try it now and see if you notice a difference. No? Then it shouldn’t surprise you that a recent meta-analysis concluded that blue-blocking lenses and coatings have no significant effect on sleep quality, comfort at the computer, or retinal health.

First, turn off your electronic devices before bed. The American Academy of Pediatrics recommends that bedrooms be “screen-free” zones for children, but we should all heed this advice. Outside of the bedroom, when you do look at your screens, lower the brightness.

As for eye strain, ensure that you have the appropriate glasses or contact lens prescription. Only an optometrist or ophthalmologist can give you this information.

You also need to take care of the surface of your eyes. We don’t just look at our computer screens, we stare at them. In fact, our blink rate plummets from about 12 blinks a minute to six. As a result, tears evaporate off the eyes, and they don’t accumulate again until we step away from the screen and start blinking. This causes inflammation on the eye’s surface. That’s why your eyes feel dry and tired after a day spent at the computer. I counsel my patients to take two steps to ensure that their eyes stay moist during long computer sessions.

First, follow the “20-20-20” rule. The American Optometric Association defines this rule as taking a 20-second break every 20 minutes to look at something 20 feet in the distance. This will allow your eyes to blink and relax. There are many apps available to help remind you to follow this rule.

Second, use a lubricating eye drop before extended computer use. This tactic will reinforce the body’s natural tears and keep the eye’s surface hydrated. But, avoid those “get-the-red-out” drops. They contain drugs that cause long-term redness and preservatives that may damage the outer layers of the eye. I have found that artificial tears labeled “preservative free” often work best.

Based on my research, my advice is don’t believe the hype about blue light and don’t waste your money on products you don’t need. Instead, keep screens out of your bedroom and dim them before bedtime and keep your eyes lubricated. And don’t forget to blink!

All screens flicker to some degree — be they TV screens, car navigation displays, monitors, tablets, and yes, even smartphone displays. In this article, we will talk a little about what flicker is, what can cause it (on smartphones in particular), and how we at DXOMARK test for it, quantify it, and measure its impact on the end-user experience.

Flicker is a quick oscillation of light output between on and off; it is measured in hertz (Hz) to quantify the frequency at which the oscillation occurs. While we may not be consciously aware of the flicker phenomenon, it’s important to understand that our eyes still physically respond to it — that is, our irises expand and contract in response to these changes in brightness. This involuntary physiological response can certainly explain why we may have a headache and particularly why our eyes can feel tired after looking at a display for an extended period of time — they have been working hard! (This is especially true when looking at a display in dark ambient conditions, such as reading in bed with the lights turned off, for reasons we’ll touch on a bit more below.)

Given the ubiquity of smartphones, it is unfortunate that the flicker on their displays (especially OLED displays) is still an issue for many people. But wait! Why do they flicker? Well, let’s remember that smartphone display hardware is based on either LCD (liquid crystal display) or OLED (organic light-emitting diode) technology. LCDs don’t emit their own light; rather, they are back-illuminated by a strip of LEDs whose light intensity is quite powerful so as to compensate for the brightness drop due to the low transmission rate of the LCD panel (caused mainly by the RGB color filter). By contrast, in an OLED display, every pixel is itself an OLED that produces its own light.

Since both LCDs and OLED smartphone displays are composed of light-emitting diodes, let’s describe how these diodes are driven. Because of a diode’s intrinsic physical properties, it cannot be dimmed by changing the intensity of the current (mA) without impacting the color of the light. So how do phone manufacturers dim displays? They make use of a technique called pulse-width modulation (PWM), which means that they turn the diodes off and on at varying rates. Because we normally should not be able to see this switching between off and on (in other words, the flicker!), our brains are fooled into perceiving the screen as simply dimmer overall (a phenomenon known as the “brain averaging effect”). How dim depends on how long the diodes are off versus how long they are on: the longer they’re off, the dimmer the screen will appear.

So both LCDs and OLED displays power their light sources differently, but both technologies are subject to flicker effect; however, it is usually more noticeable on OLED displays than on LCDs. For one thing, OLED displays and LCDs show PWM at different frequency ranges — the PWM of OLED displays range from ~50 to ~500 Hz, whereas the PWM of LCDs starts at around 1000 Hz or higher. Second, as the human eye may experience flicker sensitivity up to about 250 Hz (at least for most people), it should come as no surprise that OLED displays are more likely to cause eyestrain than LCDs.

An on/off modulation pair is called a period, and the amount of time that the diode is switched on in a period is called a duty cycle. The chart below illustrates how different PWMs affect the perceived brightness of a display:

A significant disadvantage to using PWM technology can be that when a display adjusts to its minimum brightness in very dim or completely dark ambient light conditions, the duty cycle is very short and the interval when the diode is off is proportionately much longer (for example, minimum brightness may translate to a 10% duty cycle, meaning that the diode is off for 90% of the period). At lower PWM frequencies, flicker can become much more noticeable, which helps explain why reading text or watching videos in bed at night is more likely to cause headaches and eyestrain than when viewing screens in brighter conditions.

The video below was shot with a Phantom VEO-E 340L camera at 1500 fps (as were the other videos further below), slowed down to 4 fps to show display pulse-width modulation (PWM) — the white areas separated by black lines that extend across the screen when brightness diminishes at regular intervals. You can see the difference between the Samsung Galaxy S20 Ultra 5G on the left, which has a medium duty cycle (around 60%), and the Huawei P40 Pro and the Oppo Find X2 Pro, which have long duty cycles (roughly 90%; the black lines show that the OLEDs are turned off, albeit briefly):

So how does DXOMARK measure flicker? One major way is with a device called, appropriately enough, a flickermeter (specifically, a TRD-200 from Westar Display Technologies), whose sole purpose is to measure quick oscillations in brightness. Our engineers follow a strict protocol for measuring flicker on each smartphone display: all devices are individually tested using their default settings under the exact same dark (< 0.1 lux) ambient lighting conditions, and are placed at the same distance from the flickermeter. We chart the output on this graph (which we use to compare up to four phones in our display reviews; note that you can click on the name of a phone in the legend on the bottom of the graph to remove or redraw its results):

Yes, it’s a cool-looking graph, but what does it mean? How should we read this? Well, first of all, keep in mind that these results correlate with each device’s PWM — the on/off power cycle that helps control screen brightness. The horizontal X axis show the frequency of the oscillations over time measured with the flickermeter in hertz (Hz). The vertical Y axis shows the SPD(dB)— spectral power density in decibels, which is the amount of power associated with one frequency of the signal that the display generates.

The first spike in our flicker graph appears at a phone’s listed refresh rate, but it is the highest spike — that is, the one that comes closest to or surpasses 0 dB — that is of interest to us in terms of flicker, as it indicates the PWM frequency; in this case, 241 Hz for the Samsung (S20), 362 Hz for the Huawei, 481 Hz for the OnePlus, and 240 Hz for the other Samsung (Note20). (Just in passing, you can nearly always ignore values below -40 (dB) on the graph, as they correspond to testing noise.)

The very slow-motion video below imitates the results of a flickermeter test. What is interesting to note is that from left to right, the devices scroll faster, which indicates different PWM frequencies.

In this second very slow-motion video, we included the Samsung Galaxy Note20 Ultra 5G that has a refresh rate of 120 Hz; interestingly enough, however, its PWM frequency is 240 Hz (as the flicker graph above also showed). In the video of the Note20 Ultra 5G, you can see that it has one frame on (bright) to five frames off (dark); the P40 Pro ends up with one frame on to three frames off; and the Find X2 Pro varies between one frame on to two or three frames off. All this is to say that where flicker is concerned, even a phone with a fast refresh rate like the Samsung Galaxy Note20 Ultra 5G can have a low PWM frequency and thus noticeable flicker under certain conditions. If you are sensitive to flicker, you will likely notice it on the Samsung devices at this brightness level and these PWM frequencies, but not on other devices with higher PWM frequencies.

Keep in mind that our engineers base their evaluations and the scores they assign to smartphone displays not only on the objective tests they perform with flickermeters and other instruments, but also on perceptual tests that they conduct after being specially trained to see flicker.

To further illustrate flicker, our engineers used a DSLR mounted on a translation rail and moved it quickly while it took a slow (1/10 second) shot of the three mounted smartphone displays shown below to imitate the effects of PWM. In the image of the Samsung Galaxy Note20 Ultra 5G on the left, you can see each individual white dot; on the Huawei P40 Pro in the middle, the individual dots are much closer together, but are still largely discernible; in the image of the OnePlus 8 Pro, however, the dots look more like an almost continuous line. Unsurprisingly, flicker is stronger on the devices where the white dots are further from one another — that is, devices with a lower PWM frequency.

Let’s wrap things up by first repeating that flicker on smartphones is caused by the use of pulse-width modulation that turns light-emitting diodes off and on to control screen brightness levels. As we normally perceive flicker via our peripheral vision rather than via our “attending vision” (that is, what we specifically focus our eyes on), the small size of a smartphone screen makes it less likely that we will see flicker on it (unless we hold the phone very close to our eyes) than we might when viewing content on a laptop screen or monitor. When we do see flicker, however, it’s the PWM that is the culprit; and while flicker can be reduced on a phone with a higher refresh rate, you may sometimes see flicker on it anyway if the phone’s PWM is slow (as we saw with the Samsung Galaxy Note20 Ultra 5G).

Finally, it’s also important to remember that some people are more sensitive to noticing flicker than others; in fact, even people who may not consciously perceive flicker may nonetheless be sensitive to it, winding up with headaches or eyestrain after overdoing their screen time. Such people could choose an OLED smartphone with an anti-flicker feature, or one with an LCD. As you can see in the table below, the last entry shows the data for the Xiaomi Mi 10T Pro; since it uses LCD technology, its PWM frequency is so high that it in essence eliminates the flicker issue.

This all said, you can rest assured that if our testers do discover a smartphone that has noticeable problems with flicker at its default settings, we will let you know about it as part of its Display review. (And by the way, we’ll also mention if a smartphone comes with a “flicker-free” feature or setting.)

Staring at the computer all day is horrible for your eyes. All those brightly colored pixels clashing with the lighting around you while you stare at your screen for hours on end—it"s a recipe for eye fatigue, muscle strain, and headaches.

By adhering to a few simple guidelines and by making some physical adjustments to your workspace, you can avoid putting too much strain on your eyes. Here are some tips to make your workday healthier.

Follow the 20-20-20 rule. Look away from your screen every 20 minutes for 20 seconds at a time and focus on a fixed point 20 feet away. There"s even a free web app that alerts you after 20 minutes has gone by so you know it"s time to give your eyes a rest. It"s called Protect Your Vision and it"s compatible with Chrome, Firefox and Safari.

Position your screen 20-30 inches away from your face, and make sure your eyes are level with the very top of your monitor. If you don"t have ability to adjust your screen"s height, stack some hardcover books beneath it. Raising or lowering your chair can also help. The key thing to remember is that you should be looking slightly down at your work. The center of the screen should be located between 15 and 20 degrees below horizontal eye level.

A good rule of thumb: Text should be three times the smallest size you can read from a normal viewing position. Again, that normal position should be 20 to 30 inches from your monitor. When it comes to color combinations, your eyes prefer black text on a white or slightly yellow background. Other dark-on-light combinations work fine for most people. Avoid low contrast text/background color schemes.

If you wear contacts, your eyes have to work harder when staring at a screen. Switching to glasses once or twice a week will help reduce the onset of eye strain. If you do wear glasses, consider asking your optometrist to add an anti-glare coating to your lenses. This will cut down on Some providers will even add it at no extra charge. Whether you wear corrective lenses or not, moistening eye drops are great for refreshing your eyes during the workday.

You want your monitor"s brightness to match your surrounding workspace brightness. To achieve this, look at the white background of this page. If it looks like a light source in the room, it"s too bright. If it seems dull and gray, it"s probably too dark. If you work in a shiny reflective office, applying a glare reduction filter to your screen can also provide relief.

Most monitors let you adjust the color temperature manually. It"s best to use a warmer (yellowish) color temperature in dark rooms and a colder (bluer) color temperature in bright rooms. The easiest way to optimize your monitor"s color temperature is to use F.lux. This app uses your computer"s location to determine whether the sun is up or down, then it automatically adjust your display to pre-determined color temperatures that best match the natural lighting environment.

Color temps are measured in degrees of Kelvin, with the scale ranging from 1,000 to 10,000. During the daylight hours, it"s best to keep your monitor relatively cool with a default color temperature of 6,500K. At night, the color temperature should be warmer, and around 3,400K. You can adjust your monitor"s settings manually, or you can let f.lux make the changes for you. The app also has some presets with specific color temperatures that you can select from.

F.lux is free and available on Mac, Windows, Linux, iOS, and some Android devices. If your Android phone can"t run the F.lux app, you can check out Twilight. The app performs a similar function by reducing the blue light of your phone and warming the color temperature during evening hours.Get more tech news with our Gadget Lab podcast, available on iTunes and Spotify.

Our eyes are one of the most important muscles in our bodies that we ultimately take for granted. With all the screen time we subject ourselves to with our phones, TVs, tablets and computers, we rarely give our eyes time to relax. Because of these devices, there has been a rise in people suffering from Digital Eye Strain or Computer Vision Syndrome (CVS).

The American Optometric Association (AOA) has dedicated a lot of time finding ways to help alleviate the amount of eye strain people are experiencing, and have even made March “Save Your Vision Month”. According to the AOA, there are many symptoms and causes for Digital Eye Strain.

Anytime a muscle group is used excessively, there needs to be a resting period to recover; the same goes for our eyes. The AOA and The Mayo Clinic both have an extensive list of ways to help prevent weakening the eye muscles and to alleviate the pain of CVS.

These days the computer screen is a main focal point for work or mundane errands like checking email. This is when the 20 – 20 – 20 rule needs to be applied.

If you are staring at a computer screen for an extended amount of time, try to only stay on the screen for 20 minutes, then look away from the screen and view an item at least 20 feet away for 20 seconds. This will help prevent eye soreness from excessive screen time.

If work requires constant computer use, be sure the very top of the computer is eye level so that the text and content are about 20 degrees downward and 15-20 inches away from eyes. Also, position the computer so that natural or fluorescent lighting is coming from the side and not from in front or behind the screen. Avoiding glare helps keep away that extra/ uneven lighting from bothering your eyes.

It is a good idea to upgrade your computer to an LCD screen as they are usually anti-reflective and don’t create very much glare. Also, a higher contrast and better quality will increase eye comfort and prevent straining.

You may think that you don’t need a reminder to blink, but if there is ever a time that you experience dry or itchy eyes after working on the computer or watching tv, this may be caused by not blinking enough. If you start suffering from constant dryness, ask your optometrist for artificial tear options that are right for you.

When you have to constantly look at the screen and then draw your attention away to a paper document, the eyes have little to no time to adjust from the screen’s text to the paper text. Find a way to put your documents by the screen or fairly close to it, to refrain from constant head movement via document holder or book stand.

These lenses were made with computer gamers eye health in mind. These glasses are tinted to block blue light and glare to help the eyes relax while viewing the screen. This will not only help you focus longer, but they will decrease your chances of suffering from digital eye strain.

Our eyes are just as important as every other muscle on our body. If you would like to learn more about how to improve and maintain your eye health, continue reading more articles on our website. One of our  best known center is located in Tucker GA.

table 1, enabling calculation of a total symptom score. The six-item Visual Fatigue Scale requires users to respond using a Likert scale to difficulties in seeing, strange feeling around the eyes, eyes feeling tired, feeling numb, having a headache and feeling dizzy looking at the screen. It has been applied to study symptoms following the use of e-readers, indicating that reading from liquid crystal display (LCD) screens (eg, tablet devices) triggers more subjectively reported VF than reading from paper copies or e-ink displays.

Although DES affects a huge number of individuals, its precise physiological basis remains unclear. An array of measures of visual function have been used to provide indices of VF: accommodation parameters have received a significant amount of research attention given the accommodative nature of several DES symptoms, while critical flicker–fusion frequency (CFF) and blinking characteristics have been used regularly in recent DES research.

Blinking aids maintenance of a normal ocular surface, with most blinks instigating a cycle of secretion, dispersal, evaporation and drainage of tears.et al

Increased cognitive demand (eg, reading more challenging material) exacerbates the effect of visual stressors such as low contrast or refractive error.et al

Although reduced blink rate may be a less pertinent issue now, many individuals continue to experience signs and symptoms of dry eye associated with digital device usage. Incomplete blinking, where the upper eyelid does not cover the entire corneal surface, may be more relevant to dry eye than blink rate as tear film stability can be maintained with a reduced blink rate, providing that most blinks are complete.et al

table 2), as well as hard copy text. However, reading from a hard copy was associated with a significantly lower proportion of incomplete blinks (0%–5%) compared with reading from a tablet (14.5%), expanded computer display (13.5%) or electronic reading (9%; see table 2). The specific influence of digital devices on incomplete blinks is unclear, and further research is needed to address this issue, along with the possible benefits of blink training.

Accommodative facility, the ability to make rapid changes in accommodation response, may be pertinent to computer use, as switching fixation from the screen to other material or into the distance occurs frequently. Among 153 symptomatic computer users examined at a specialist clinic, poor accommodative facility was the most common diagnosis, detected in 31 (20.3 %) patients.et al

Along with accommodation and convergence, the pupil response is the third component of the near triad. Changes in pupillary characteristics and response have been explored as potential indicators of VF. Monitoring pupil diameter within-task has led to the hypothesis that an increase in pupil size indicates VF, due to detrimental effects on depth of focus.et al

Dry eye is considered a significant aetiology of DES, with factors such as altered blinking characteristics, environmental influences and gaze angle considered relevant to dryness with digital device use. Office environments commonly feature low humidity, ventilation fans, air conditioning and airborne dust/toner particles, which may promote corneal drying.

Given the impact of digital device usage on blinking characteristics, blink training may be helpful in the management of DES symptoms linked to dry eye. Increasing blink rate through use of an audible prompt signal every 4 s during a computer task was not found to alter symptom scores,

Correction of refractive error (notably astigmatism) and presbyopia is accepted as an important intervention in DES sufferers. Double-masked, randomised studies have established that even 0.50–1.00 D of uncorrected simulated astigmatism impacts negatively on subjective visual comfort,

The variety of working distances involved in using different digital devices can prove problematic for individuals requiring a near vision add. Small fonts are common on smartphones due to reduced screen size, and a mean working distance of 32.2 cm was established in adults undertaking a web-based smartphone task,

UK employees using display screen equipment (DSE) habitually as a significant part of their work are entitled to a sight test funded by their employer, along with spectacles specifically for screen use.

Accommodative anomalies including poor facility and high lag may reduce visual comfort during nearwork, including computer use. Clinically, accommodative facility may be assessed with plus and minus sphere flipper lenses while the patient fixates a near target, counting the number of cycles ‘cleared’ in 1 min (cpm).

Vergence dysfunctions include various motor disorders, for example, convergence insufficiency, decompensated heterophoria and poor vergence facility. Individuals with binocular vision problems experience greater visual symptoms with prolonged use of the eyes.et al

Light exposure is also the main factor involved in setting circadian rhythms. Melatonin hormone is released in dim light conditions and is involved in the physiological control of sleep. Its release from the pineal gland is controlled by a pathway originating from the intrinsically photosensitive retinal ganglion cells containing melanopsin, which has a peak sensitivity of approximately 482 nm,

Given both the putative link between the blue light emitted from modern digital devices and ocular complaints and the commercial availability of blue-filtering lenses for treatment of DES, several authors have explored the impact of blue light-reducing spectacles on symptoms and objective measures of VFtable 3). There is a lack of consensus in the findings of these studies, and a recent systematic review of the literature called for high-quality research, ideally in the form of randomised control trials, to address the health effects of blue blocking spectacle lenses.

Wraparound goggles with low-blocking, medium-blocking and high-blocking properties worn for computer work for 1 week each. Schirmer test and subjective questionnaire completed after each week.No significant change in Schirmer test values for any group or filter.

Lin et al, 2017n=36 participants in three groups of 12. Each group wore no blocking, low-blocking or high-blocking spectacles for 2-hour computer task.

Further to improving subjective comfort, management of DES among computer workers may confer significant economic advantages. The experience of symptoms can reduce work accuracy,

Sitting up straight decreases pressure on your neck and back. It’s also good practice to sit at least 20 inches, or an arm’s length, away from your computer screen, with the keyboard close and directly in front of you.

Having a balanced diet that includes green leafy vegetables, citrus fruits, nuts, fish and carrots gives you Omega-3, Vitamins A, C and E — all vital for healthy eyes.

2.Tested by an independent third-party laboratory according to the ISO 22196 standard (Measurement of antibacterial activity on plastics and other non-porous surfaces), using bacterial cultures that include Escherichia coli and Staphylococcus aureus, with an antibacterial activity result of R > 2 compared to an untreated surface. R = 2 indicates a 99.9% reduction in bacterial activity.

AMOLED burn-in on screens and displays is permanent. Fortunately, you can slow it down and reduce its visibility by using a few simple tricks, which can also increase battery life.

Each pixel within an Active Matrix Organic Light-Emitting Diode (AMOLED) comprises red, green, and blue (and sometimes white) sub-pixels. When they emit light, they decay. Burn-in appears because individual sub-pixels lose brightness at different rates, depending on its color. The most-used light-emitting sub-pixels, such as for navigation and status icons, wear out first, leading to uneven light production.

So the more you use the device, the more visible its burn-in. And the longer you display the same image, the more that image"s outline will persist on the display.

It doesn"t help that many user-interface buttons are white. For an AMOLED panel to produce white light, the display switches on three different sub-pixels in proximity to one another. Each sub-pixel produces a different color: red, blue, and green. Together they appear white to the human eye. However, each of the three colors wears out at different rates, depending on the manufacturer.

For the AMOLED on most smartphones, red sub-pixels are the most durable, followed by green. Blue decays the fastest. When you see burn-in, it"s often caused by a weakening blue sub-pixel. All "fixes" aim at addressing the failing blue sub-pixel. Remember, there are also tools available to fix dead pixels.

Everyone with an OLED display has some burn-in. But often, it"s not fully visible unless you display a solid color at maximum brightness. The Android operating system has access to many apps that detect burn-in damage. The best of these is Screen Test.

Screen Test is ultra-simple: install and run the app. Touching the screen shifts between colors and patterns. If you see a persistent image impression or blotchy coloration, you have burn-in.

For my AMOLED phone, I"ve taken every precaution against screen burn-in. Even so, the display is still a little blotchy after over a year of use. Fortunately, there are no indications of burn-in where the navigation buttons are.

Android 10"s dark mode finally allows for Android system menus and apps to appear dark in color. It will turn Chrome"s user interface black, as well as the Settings menu, navigation bar, and notifications shade.

Some might notice that the stock wallpapers in Android aren"t usually suited for OLED screens. OLED screens consume very little energy when displaying the color black, and they do not burn-in when displaying black. Unfortunately, older Android versions don"t include a solid black wallpaper option.

Fortunately, the free app Colors, from developer Tim Clark, allows users to change their wallpaper to a solid color. Just install and run the app, then choose a solid black background as the new wallpaper.

Using black wallpaper will improve the battery performance of your device, so this one is a win-win. However, if you have Android 8.0 or newer, you might already have solid colors available as a wallpaper.

If you don"t have Android 10 or newer, the default Android Launcher isn"t OLED friendly. In Android 5.0, it forces the App Drawer wallpaper to white (the worst color for OLED screens). One of the best launchers for darker colors is Nova Launcher. Not only is it more responsive, it offers better customization options.

Firefox Mobile is infinitely customizable. While they, unfortunately, removed many of their browser"s mobile add-ons, you can still turn entire webpages black. And, on top of that, Firefox includes a dark theme.

I recommend installing an add-on. The easiest-to-use add-on is Dark Reader. Dark Reader does more than just change the color of Firefox"s user interface; Dark Reader can change webpages" to black backgrounds with red text, reducing eye strain and burn-in while also improving battery life.

Android"s dark-themed virtual keyboard options can reduce burn-in (and improve battery life). The best of these is SwiftKey, which allows users to change the color of their keyboards. The best SwiftKey theme I"ve seen so far is the Pumpkin theme. If you turn on Android"s dark theme, it automatically turns the keyboard black. In this case, you can simply use the default keyboard.

There are a few other burn-in repair tools, but I don"t recommend them since they either require root access and/or can increase screen damage. However, for reference, you can read about them below and why using them is a bad idea. They fall into two categories:

I do not recommend using this option unless your screen is already trashed. It will cause additional damage but may reduce the appearance of already existing on-screen burn. Inverting colors simply reverses the colors displayed on your screen. Whites become blacks and vice-versa.

If you use the phone with the colors inverted for extended periods of time, it will burn-in the areas surrounding the burned-in navigation bar, reducing its visibility.

Android 4.0 (Ice Cream Sandwich) introduced the Invert colors option to help the visually impaired. It"s not at all designed to combat burn-in and remains experimental. To invert colors, take the following steps:

The reason is pretty simple: AMOLED burn-in occurs as a natural part of an organic LED"s life cycle. Therefore, tools that claim to fix AMOLED burn-in will cause uniform damage across all AMOLED pixels thus potentially worsening its image quality.

None of these methods will stop the inevitable and slow destruction of your device"s screen. However, using all the recommended options in this article will dramatically decrease the rate at which it decays. That said, some of the oldest AMOLED phones have very little burn-in. The decay of organic LEDs is almost entirely aesthetic, particularly on newer phones.

Computer users complain of blurred vision, tired eyes, dry eyes and headaches on a daily basis. Many blame their computers for needing eyeglasses, while others claim that staring at a screen has caused their myopia (nearsightedness) to worsen. High tech employees worry about computer monitor radiation. What they all share is their concern about permanent, irreversible damage to their eyes.

The good news is that extensive research into eye health in Israel and North America has conclusively and repeatedly proven that digital screens do not cause eye damage. Nor has it been proven that intense computer activity can lead to or affect myopia, as in the case of high tech workers. That said, everyone agrees that computer use may cause temporary eye problems, most of which can easily be solved or prevented by simple changes in work habits.

As a general rule, if eye strain symptoms appear following a short period of computer use, this means that there is a specific eye health issue that should be addressed. However, developing tired eyes after eight hours of non-stop intense visual activity is totally normal. After all, wouldn’t you expect your legs to tire after running a marathon?" - Doctor Andrew Fink MD.

This article was written by Doctor Andrew Fink MD, Eye Surgeon, Fellow of the Royal College of Ophthalmologists. We are very grateful for his contribution.

Eye strain occurs when your eyes get tired from intense use over a prolonged period of time, or when the muscles in your eyes fatigue. This means that eye strain can be caused by any number of events or situations, such as reading sheet music in a small font, composing in the dark or even driving a car for extended periods, to name a few.

There is no scientific evidence proving that eye strain causes permanent damage. Eye strain is generally associated with symptoms such as blurred vision, tiredness, soreness, itching of the eyes or headaches.

But these are just symptoms of eye discomfort, in the same way that muscles are often sore after exercising at the gym, which is an uncomfortable – yet harmless – side effect. By introducing good habits into your daily routine eye-strain should be prevented, or at least counteracted.

The size of the pupil changes according to the brightness of what the eye is looking at. So if the ambient lighting is continuously changing, the pupil will work more intensely leading to the muscles feeling tired.

The size of the pupil changes according to the brightness of what the eye is looking at. So if the ambient lighting is continuously changing, the pupil will work more intensely leading to the muscles feeling tired.

Wearing eyeglasses with an incorrect prescription will cause the eyes to tire more quickly when intensively staring at a screen for extended periods of time.

Our eyes are designed to look down slightly when reading or doing close-up work. Looking straight ahead at a focal point, or worse upwards or sideways, will cause additional strain on the eye muscles.

Lastly, the blue light factor has been extremely controversial among scientists. Although it can be found in almost everything from sunlight to fluorescent and LED lighting, it is actually considered as having both positive and negative effects on the eyes. Light is made up of electronic particles, and blue light has a very short wavelength thereby producing more energy.

Blue light can be more difficult to focus and may contribute to discomfort over longer viewing periods. Laboratory studies have also proven that there is a link between retinal problems and high exposure to blue light. However, computers produce far less blue light than natural sunlight, and the threshold past which exposure becomes “high” has not yet been determined.

On the other hand, blue light has also been proven to boost alertness and cognitive function, and help release happy endorphins. For those worried by the effect of blue light, there is no shortage of blue light filters for computer screens or blue light-blocking computer glasses.

Let’s start by having a closer look at the technical characteristics of the two main screens on the market: E-Ink (Electrophoretic Ink) and LCD (Liquid Crystal Display). E-Ink is an electronic paper display technology integrated into e-book reading devices such as Kindle. LCD screens are found in iPads, tablets, smartphones, televisions and computers.

Basically, E-Ink screens offer a reading experience similar to that of reading a paper book, whereas LCD screens offer a digital experience. Based on these preliminary findings, it would make perfect sense to believe that E-Ink screens are better for the eyes. Surprisingly, however, Dr. Fink and the American Optometric Association state that “the nature of the screen (LCD vs. E-Ink) is largely irrelevant”. So, why aren’t E-Ink screens considered as being naturally better for the eyes?

One recurring argument is that E-Ink screens are preferable because backlit screens damage the eyes. As it turns out, this isn’t true. According to the American Optometric Association, “backlit screens do not make any difference as our eyes naturally adjust to the amount of light we are exposed to”.

Furthermore, since LCD screens are backlit they offer built-in options to manually adjust screen brightness. Most LCD screens do this automatically by calculating the ratio of external vs screen lighting.

Another argument comes from Carl Taussig, director of Hewlett-Packard‘s Information Surfaces Lab. According to him, “the new LCDs don’t affect your eyes, today’s screens update every eight milliseconds, whereas the human eye is moving at a speed between 10 and 30 milliseconds.”

To improve the reading experience, Apple has introduced the Night Shift and True Tone features. Night Shift is designed to automatically adjust the display color balance in order to reduce brightness. True Tone automatically changes the white point and color balance of the display based on real-time measurements of the ambient light falling on the screen. The idea is to make the display behave more like paper reflecting ambient light and taking on its color.

The adaptive design of LCD screens means that