tft lcd eye strain quotation

American Optometric Association (AOA) defines CVS or digital eye strain as a group of eye and vision-related problems that results from prolonged usage of computers, tablets, e-readers, and cell phones which causes increased stress to near vision in particlular.

The symptoms reported in children with a prolonged history of screen exposure include reduced attention span, poor behaviour, irritability, dry eyes, ocular irritation, eye strain, headache, neck pain and shoulder pain.

Reduced blinking: Though the normal blinking rate is around 15-20 /min, the blinking rate is significantly reduced while working on VDT. This causes the eye to be opened for a longer duration and thereby increases the chances of dryness.

Evaluation of a patient with CVS can be performed using objective or subjective methods. Associated Dry eye disease should be evaluated as denoted in the eyewiki articles available at https://eyewiki.aao.org/Dry_Eye_Syndrome and https://eyewiki.aao.org/Dry_eye_diagnosis_and_management.

Computer work and work that needs concentration are known to reduce the blinking rate and thereby increase the exposure time of ocular surface and dry eye.

To reduce eye strain, the room lighting may be adjusted and the contrast of the computer screen may be increased. Matte screen filter can be considered.

Workplace Wellness EyeStrain Infographic_2020 taken from: Looks Like the Home Office is Here to Stay. Here’s How to Protect Your Eyes [Internet]. Am. Acad. Ophthalmol.2021 [cited 2021 May 31];Available from: https://www.aao.org/newsroom/news-releases/detail/protect-your-eyes-in-home-office ©American Academy of Ophthalmology

Individuals who work for a prolonged period at computer screens, should take breaks and remember to blink frequently during work to reduce the CVS symptoms. This relaxes and restores the accommodative system reducing digital eye strain. According to the famous 20-20-20 rule, every 20 minutes, an individual should take the eye off from the screen for about 20 seconds and look at a distant object (situated at 20 feet away).

Environmental factors that can aggaravate dry eye symptoms include low ambient humidity, air conditioners, and ventillation fans. Modifications to improve humidity and ergonomic design of the workplace should be planned to reduce dry eye as mentioned under ergonomics.

Lubricating drops may reduce dry eye symptoms including dryness, irritation, ocular discomfort, tiredness and difficulty in focusing though complete resolution may not occur.

Blinking exercises every 20 minutes by closing the eyes for 2 seconds, opening and again closing for 2 seconds followed by squeezing for 2 seconds showed positive effect on alleviating dry eye symptoms and signs.

Polyvinyl alcohol, dextran and polyvinyl pyrrolidine have been found to be effective for evaporative dry eyes but with less evidence. Lubricants ranging from carboxymethyl cellulose to highly viscous topical drops and ointments reduce the symptoms of dry eye but do not increase the blink rate.

Omega 3 fatty acids were shown to improve dry eye symptoms and Nelson grade in CVS-related dry eye. Freedom from symptoms was reported in 70% cases in a study by Bhargava and colleagues.

According to the American Academy of Ophthalmology "There is no scientific evidence that the light coming from computer screens is damaging to the eyes. Because of this, the Academy does not recommend any special eye wear for computer use."

Such glasses may increase the humidity and reduce evaporation of tear film thus reducing the dry eye symptoms. It may also protect from particulate matters/irritants in the air.

Computer vision syndrome (Digital eye strain) [Internet]. 2021 [cited 2021 May 31];Available from: https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/computer-vision-syndrome?sso=y

Sheppard AL, Wolffsohn JS. Digital eye strain: prevalence, measurement, and amelioration. BMJ Open Ophthalmol. 2018 Apr 16;3(1):e000146. doi: 10.1136/bmjophth-2018-000146. PMID: 29963645; PMCID: PMC6020759.

Cohen Y, Segal O, Barkana Y, Lederman R, Zadok D, Pras E, Morad Y. Correlation between asthenopic symptoms and different measurements of convergence and reading comprehension and saccadic fixation eye movements. Optometry. 2010 Jan;81(1):28-34. doi: 10.1016/j.optm.2008.10.019. PMID: 20004875.

Marshall J. Light in man"s environment. Eye (Lond). 2016 Feb;30(2):211-4. doi: 10.1038/eye.2015.265. Epub 2016 Jan 8. PMID: 26742864; PMCID: PMC4763140.

Zhao ZC, Zhou Y, Tan G, Li J. Research progress about the effect and prevention of blue light on eyes. Int J Ophthalmol. 2018 Dec 18;11(12):1999-2003. doi: 10.18240/ijo.2018.12.20. PMID: 30588436; PMCID: PMC6288536.

Miyao M, Hacisalihzade SS, Allen JS, Stark LW. Effects of VDT resolution on visual fatigue and readability: an eye movement approach. Ergonomics. 1989 Jun;32(6):603-14. doi: 10.1080/00140138908966135. PMID: 2776740.

Lin JB, Gerratt BW, Bassi CJ, Apte RS. Short-Wavelength Light-Blocking Eyeglasses Attenuate Symptoms of Eye Fatigue. Invest Ophthalmol Vis Sci. 2017 Jan 1;58(1):442-447. doi: 10.1167/iovs.16-20663. PMID: 28118668.

Ide T, Toda I, Miki E, Tsubota K. Effect of Blue Light-Reducing Eye Glasses on Critical Flicker Frequency. Asia Pac J Ophthalmol (Phila). 2015 Mar-Apr;4(2):80-5. doi: 10.1097/APO.0000000000000069. PMID: 26065349.

Looks Like the Home Office is Here to Stay. Here’s How to Protect Your Eyes [Internet]. Am. Acad. Ophthalmol.2021 [cited 2021 Jun 1];Available from: https://www.aao.org/newsroom/news-releases/detail/protect-your-eyes-in-home-office

Alabdulkader B. Effect of digital device use during COVID-19 on digital eye strain. Clin Exp Optom. 2021 Feb 22:1-7. doi: 10.1080/08164622.2021.1878843. Epub ahead of print. PMID: 33689614.

Guillon M, Maissa C, Pouliquen P, Delval L. Effect of povidone 2% preservative-free eyedrops on contact lens wearers with computer visual syndrome: pilot study. Eye Contact Lens. 2004 Jan;30(1):34-9. doi: 10.1097/01.ICL.0000101489.13687.9A. PMID: 14722467.

Acosta MC, Gallar J, Belmonte C. The influence of eye solutions on blinking and ocular comfort at rest and during work at video display terminals. Exp Eye Res. 1999 Jun;68(6):663-9. doi: 10.1006/exer.1998.0656. PMID: 10375429.

Acosta MC, Gallar J, Belmonte C. The influence of eye solutions on blinking and ocular comfort at rest and during work at video display terminals. Exp Eye Res. 1999 Jun;68(6):663-9. doi: 10.1006/exer.1998.0656. PMID: 10375429.

Bhargava R, Kumar P, Phogat H, Kaur A, Kumar M. Oral omega-3 fatty acids treatment in computer vision syndrome-related dry eye. Cont Lens Anterior Eye. 2015 Jun;38(3):206-10. doi: 10.1016/j.clae.2015.01.007. Epub 2015 Feb 16. PMID: 25697893.

Singh S, Downie LE, Anderson AJ. Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial. Am J Ophthalmol. 2021 Feb 12;226:243-251. doi: 10.1016/j.ajo.2021.02.010. Epub ahead of print. PMID: 33587901.

The wide range of conditions over which LCD monitors are used means that it is desirable to produce displays whose luminance (brightness) can be altered to match both bright and dim environments. This allows a user to set the screen to a comfortable level of brightness depending on their working conditions and ambient lighting. Manufacturers will normally quote a maximum brightness figure in their display specification, but it is also important to consider the lower range of adjustments possible from the screen as you would probably never want to use it at its highest setting. Indeed with specs often ranging up to 500 cd/m2, you will certainly need to use the screen at something a little less harsh on the eyes. As a reminder, we test the full range of backlight adjustments and the corresponding brightness values during each of our reviews. During our calibration process as well we try to adjust the screen to a setting of 120 cd/m2 which is considered the recommended luminance for an LCD monitor in normal lighting conditions. This process helps to give you an idea of what adjustments you need to make to the screen in order to return a luminance which you might actually want to use day to day.

Changing the display luminance is achieved by reducing the total light output for both CCFL- and LED-based backlights. By far the most prevalent technique for dimming the backlight is called Pulse Width Modulation (PWM), which has been in use for many years in desktop and laptop displays. However, this technique is not without some issues and the introduction of displays with high brightness levels and the popularisation of LED backlights has made the side-effects of PWM more visible than before, and in some cases may be a source of visible flicker, eyestrain, eye fatigue, headaches and other associated issues for people sensitive to it. This article is not intended to alarm, but is intended to show how PWM works and why it is used, as well as how to test a display to see its effects more clearly. We will also take a look at the methods some manufacturers are now adopting to address these concerns and provide flicker-free backlights instead. As awareness grows, more and more manufacturers are focusing on eye health with their monitor ranges.

Pulse Width Modulation (PWM) is one method of reducing the perceived luminance in displays, which it achieves by cycling the backlight on and off very rapidly, at a frequency you can’t necessary detect with the naked eye, but which could lead to eye issues, headaches etc. This method generally means that at 100% brightness a constant voltage is applied to the backlight and it is continuously lit. As you lower the brightness control the perceived luminance for the user reduces due to a number of possible controlling factors:

Where the effect of flicker can really come into play is any time the user’s eyes are moving. Under constant illumination with no flickering (e.g. sunlight) the image is smoothly blurred and is how we normally perceive motion. However, when combined with a light source using PWM several discrete afterimages of the screen may be perceived simultaneously and reduce readability and the ability of the eyes to lock onto objects. From the earlier analysis of the CCFL backlighting we know that false colour may be introduced as well, even when the original image is monochromatic. Below are shown examples of how text might appear while the eyes are moving horizontally under different backlights.

It is important to remember that this is entirely due to the backlight, and the display itself is showing a static image. Often it is said that humans cannot see more than 24 frames per second (fps), which is not true and actually corresponds to the approximate frame rate needed to perceive continuous motion. In fact, while the eyes are moving (such as when reading) it is possible to see the effects of flicker at several hundred hertz. The ability to observe flicker varies greatly between individuals, and even depends on where a user is looking since peripheral vision is most sensitive.

100-120Hz flickering of fluorescent lights has in fact been linked to symptoms such as severe eye strain and headaches in a portion of the population, which is why high-frequency ballast circuits were developed that provide almost continuous output. Using PWM at low frequencies negates the advantages of using these better ballasts in backlights because it turns an almost constant light source back into one that flickers. An additional consideration is that poor quality or defective ballasts in fluorescent backlights can produce audible noise. In many cases this is exacerbated when PWM is introduced since the electronics are now dealing with an additional frequency at which power usage is changing.

It is also important to distinguish the difference between flicker in CRT displays and CCFL and LED backlit TFT displays. While a CRT may flicker as low as 60Hz, only a small strip is illuminated at any time as the electron gun scans from top to bottom. With CCFL and LED backlit TFT displays the entire screen surface illuminates at once, meaning much more light is emitted over a short time. This can be more distracting than in CRTs in some cases, especially if short duty cycles are used.

As we said at the beginning, this article is not designed to scare people away from modern LCD displays, rather to help inform people of this potential issue. With the growing popularity in W-LED backlit monitors it does seem to be causing more user complaints than older displays, and this is related to the PWM technique used and ultimately the type of backlight selected. Of course the problems which can potentially be caused by the use of PWM are not seen by everyone, and in fact I expect there are far more people who would never notice any of the symptoms than there are people who do. For those who do suffer from side effects including headaches and eye strain there is an explanation at least.

Is LCD or AMOLED better for eyes？The full English name of LCD is Liquid Crystal Display, which is a general term. According to its driving method, it can be divided into various specifications. Most monitors and laptops on the market today are thin-film transistors. Because TFT has better color saturation and viewing angles than other technologies, it is also the mainstream specification on the market today. The models on the market are mainly based on TFT, and LCD has now become synonymous with the term TFT display. Next, I will tell you in detail which LCD screen or OLED screen is better for the eyes.

Both OLED and LCD can cause damage to the eyes, because both OLED and LCD emit blue light, which is unavoidable. However, users can turn on the eye protection mode of the mobile phone to reduce the damage of blue light to the eyes. In addition, OLED"s dimming technology and LCD"s blue backlight are also one of the reasons for the "eye-hurt". OLED adopts PWM low-frequency dimming technology, which is a technology that adjusts the brightness through the rapid flickering of the light-emitting unit, so looking at the screen for a long time will cause eye fatigue. The blue backlight of an LCD monitor emits high-energy short-wave blue light.

In terms of manufacturing process, OLED adopts self-luminous technology and has no backlight layer, so this screen can be made very thin. In addition, each light-emitting unit of OLED can emit light independently when it emits light, and has the function of color screen display. LCD is composed of backlight layer, liquid crystal layer, color filter and other components, and the screen is made of inorganic materials, so the service life of this screen is relatively long.

Is LCD or AMOLED better for eyes？The above is the difference between lcd and oled. Users should try to avoid staring at the phone screen for a long time. Reduce LCD and AMOLED viewing time in dark environments. If you have the habit of reading late at night, you also need to turn on a light to neutralize the strobe light. Moisten your eyes with eye drops when your eyes are dry.

Furthermore, this 21.5″ 1920×1080 monitor is 34 inches from my eyes, so that I can’t distinguish individual pixels. The enlarged text appears very crisp from this distance, and this means easier reading and less eye fatigue.

Sit far from the monitor and increase screen font size to increase effective resolution. See “Reduce Eye Fatigue” section below for how to calculate this distance for your monitor.

Steve Jobs claims that you can’t distinguish individual pixels on a device with more than 300 PPI such as the iPhone 4 or iPod Touch 4g, which both have a 326 pixels per inch (PPI) “Retina Display.” He’s right. That is likely the main reason my eyes get less tired with this device than any other LCD display I’ve used.

Have you ever noticed how a massive HDTV looks great 6 or more feet away, but not so great close up? You can see the individual pixels on a 46” HDTV if you’re 3 feet away, but not if you’re 6 feet away. The same principal applies to an LCD display. Move it twice as far away, and you’ll only be able to distinguish half the detail.

In other words, you cannot distinguish individual pixels on a 326 PPI Retina Display that is more than 10.55 inches away from your eyes unless you have better than 20/20 vision. The same applies to my 103 PPI monitor at a distance of greater than 33.4 inches.

Enlarged text nearly three feet from my eyes is very easy to read. Another subtle benefit is that page elements such as tabs, menus, and status bars do not get larger. They look tiny relative to the enlarged text, so they’re less noticeable and less distracting.

Note that by enlarging your web pages or documents, you do end up with less information on the screen. I find that I don’t usually need 1920×1080 pixels worth of information on a screen at one time. But when I do, I can simply move the screen closer to my eyes. Yes I lose the benefits of having the equivalent of a Retina Display, but the trade-off is sometimes worthwhile, particularly with large spreadsheets.

Inexpensive 19″, 1280×1024 monitors will do. But with 86 PPI, these monitors need to be 40” away to achieve the equivalent resolution of a Retina Display that is 10.55 inches from your eyes. Worse, you’ll need to enlarge the text in order to read it and then won’t be able to see much more information than you can on an iPod Touch. More likely is that you won’t want to position your 1280×1024 monitor so far away, so you’ll notice the individual pixels.

Luckily, high quality 1920×1080 monitors can be purchased for $150 to $400 these days. The diagonal length of monitors with this resolution ranges from 21.5” to 26”, but the larger sizes of these monitors usually cannot pivot. Furthermore, the bigger the monitor is, the farther you’ll need to place it away from your eyes.

The 21.5” diagonal screen size was the smallest I could find on a 1920×1080 monitor. It needs to be only 33.4” from my eyes (to achieve the same effect as a Retina Display at 10.55 inches), as opposed to the 37.5” required for a 24” display. Closer is better so I don’t have to lean forward as far when I need to look at something small.

The Fellowes Compact TFT/ LCD Monitor Riser is suitable for use with either flat screen TFT or LCD monitors and has been ergonomically designed to help reduce shoulder, neck and eye strain. The unique height adjustment allows for individual customisation from 76mm to 114mm to ensure a comfortable viewing angle can be adopted. The monitor platform is able to rotate 45 degrees to accommodate quick and easy shared viewing of the screen.

There are a number of options for reducing digital eye strain and your exposure to blue light which include workspace ergonomics, computer glasses, specialized lenses and protective coatings. The first step is to get a comprehensive eye exam, making sure you speak to your eye doctor about how often you use a computer and digital device. This will help your doctor to get the full picture of your eye and vision needs in order to determine which option is best for you. It was also help the doctor to identify any underlying issues that could be worsening your symptoms.

Symptoms of computer or digital eyestrain tend to be noticed after someone has used a digital device for as little as 2 hours a day. Studies show that 60% of people spend more than 6 hours a day in front of a digital device and 70% of adults report some symptoms of computer vision syndrome (CVS) which include:

Digital eye strain also impacts your ability to focus and lessens productivity. Most people do nothing to ease their discomfort from these symptoms because they are not aware of the cause.

Reduce Glare: Glare is a significant cause of computer eyestrain so it is important to minimize it as much as possible. Set up your computer where glare from windows won’t affect your screen or cover windows when this is not possible. Glare can also reflect from walls and shiny finishes on desks and other surfaces. An anti-glare screen on your monitor or an anti-reflective (AR) or anti-glare coating applied to your eyewear can also help to minimize glare and the strain it causes to your vision.

Screen size and distance: You want to make sure you are using a high quality (such as a flat LCD) screen that has a relatively large display (look for a diagonal screen size of at least 19 inches) and is located directly in front of your line of vision. Your viewing distance should be about an arm’s length away with the top of the monitor at about eye level or slightly below.

Keep Eyes Moist:When viewing a digital screen or monitor for an extended period of time, we tend to blink less frequently (about ⅓ as often as we should). Blinking however, is critical for keeping the eyes moist, which allows them to remain clear and comfortable and to avoid dry eyes, irritation, blurry vision or eye fatigue.

Focus on blinking by setting a timer for every 20 minutes and slowly closing and opening your eyes 10 times. Keep a bottle of artificial tears handy to use when your eyes are feeling dry.

Give Your Eyes a Break: Schedule and take frequent breaks from your screen. Follow the 20-20-20 rule; every 20 minutes, look at something 20 feet away for 20 seconds. Take this time to stand up and stretch your back, neck and legs as well.

Computer glasses reduce eye strain by adjusting the focus slightly so your eyes feel like they are focusing on something further away. They also have a tint to remove the glare and block blue light from entering into your eyes. There are a number of options for computer eyewear, both if you need prescription eyewear and not. Speak to your eye doctor about what the best options are for you.

It is important to know that both adults and children alike are susceptible to computer eye strain from computers and digital devices. With the growing use of such devices in our everyday lives it is important to start educating ourselves and our children on how to combat the negative effects of these habits.

When reading online, your readers face these special problems:Light. Reading online is like reading with a flashlight shining in your eyes. And you know what happens when you spend your day staring at a lightbulb.

Blinking. People blink less often when reading online than when reading print. That’s a problem, because blinking is what keeps our eyes moist and relaxed. They also open their eyes wider when reading on the screen. That makes their tears evaporate faster and leads to dry eye.

Scrolling. The human eye has a normal reflex called optokinetic nystagmus. That’s scientist talk for the way our eyes flit across the screen to follow scrolling type. That constant jumping up and down can wear your readers out, cause eyestrain and cause readers to feel a little seasick. (So you can cause readers to throw up from what you write online.)

Some 12 million Americans visit eye doctors each year because of computer-related problems, according to the American Optometric Association. That’s one out of every five people who come in for an eye exam.

Some 50% to 90% of computer users suffer from eye strain, according to WebMD. No wonder computer vision syndrome is recognized by the American Optometric Association. It includes these symptoms:Sore or irritated eyes

People who spend hours staring at a screen suffer chemical changes in their tears similar to folks with dry eye, according to a 2014 Japanese Dry Eye Society study. Symptoms include irritation, burning and blurred vision.

Don’t make your reader turn a blind eye to your message. When you write web content, get to the point faster, organize better, make it easier to read and more skimmable.