Lcd Monitors: Eye Strain Culprits Or Just Another Screen?

With the average person spending an increasing amount of time in front of screens, it is important to consider the impact of screens on eye health. LCD screens emit blue light, which can cause digital eye strain and lead to migraines, blurry vision, headaches, and dry or tired eyes. Blue light exposure can also cause permanent damage to the eyes, such as macular degeneration, and disrupt sleep patterns. While there is no conclusive evidence that LED screens are better for eye health, they do provide better readability and more robust dimming options, which can reduce digital eye strain.

Blue light exposure

Blue light is a high-energy light with short wavelengths. It is emitted by the sun, fluorescent light bulbs, and light-emitting diodes (LEDs). Blue light is also present in digital screens such as computer monitors, smartphones, tablets, and TVs.

Blue Light and Your Eyes

LCD screens use a layer of liquid crystals powered by an electric current and backlit by a neon tube. LED screens, on the other hand, are basically LCD screens with better lighting. LED screens are more common and provide better readability and contrast than LCD screens. They also offer more robust dimming options and have integrated blue light reduction applications. However, LED screens emit more harmful blue light than LCD screens.

Blue Light and Sleep

Blue Light and Cancer

Blue Light and Children

Children's eyes do not filter blue light as well as adults' eyes. Too much exposure to blue light from device screens may increase children's chances of developing obesity, nearsightedness, and attention issues.

Protecting Your Eyes from Blue Light

• Reduce screen time.
• Use software that reduces blue light from screens.
• Wear blue light glasses.

Flicker and glare

LCD monitors use backlights to display images. The number of reported cases of eye fatigue caused by screen flickering has increased since the popularisation of LED-backlit monitors. LCD monitors can even affect the eyes of people who don't notice backlight flickering.

Flicker is the result of backlight dimming (brightness control). There are two dimming techniques applied to LCD monitors: PWM (Pulse-Width Modulation) and DC (Direct Current). PWM controls brightness by cycling the backlight on and off, whereas DC controls brightness by adjusting the power supply. PWM offers a wide brightness adjustment range and a simple circuit design, but it can cause high-speed cycles that may result in flicker on LED screens. DC, on the other hand, doesn't cause flicker but has its own drawbacks, such as difficult colour reproduction with dark images and complicated circuitry.

Some LCD monitors use a hybrid solution, combining both PWM and DC dimming methods. For example, the FlexScan frameless monitors use PWM at high brightness settings and DC at middle to low brightness settings. This approach eliminates flicker while maintaining colour stability, even at low brightness.

While a user may not be aware of the flicker, it can cause a number of issues, including eye strain and fatigue. Studies reveal that after only 3 to 4 hours of using a traditional computer monitor, 90% of users may experience eye fatigue. Short-term use of such a monitor may lead to symptoms such as eye irritation, dryness, short-sightedness, blurry vision, and headaches. Continued exposure could potentially cause irreversible damage to the retinal cells and even lead to age-related macular degeneration and loss of vision.

To reduce the negative impact of flicker, you can opt for a flicker-free monitor, which maintains a steady stream of light. Flicker-free technology helps to reduce eye strain, fatigue, and irritation, as well as the development of Computer Vision Syndrome.

In addition to choosing a flicker-free monitor, there are other steps you can take to protect your eyes. Ensure that your workstation is properly lit, neither too dim nor too bright, to reduce glare and reflection. Adjust the colour temperature of your screen to use warmer tones and fewer blue ones, as cooler colour profiles emit more harmful blue light. Maintain a proper viewing distance, with your screen positioned 15 to 20 degrees below eye level and 20 to 28 inches away from your eyes. Finally, remember to take breaks! Follow the 20-20-20 rule: every 20 minutes, focus on a point 20 feet away from your screen for 20 seconds.

Viewing distance

• Ensure your screen is positioned at a comfortable distance from your eyes. The ideal distance will vary depending on the size of your screen and your personal preferences, but a good rule of thumb is to position your screen at arm's length away. This will help reduce eye strain and prevent fatigue.
• Adjust the screen height so that your eyes are level with the top of the screen. This will allow you to look slightly downwards when viewing the screen, which is more comfortable for your eyes and neck.
• If you wear prescription glasses, consider investing in a pair with an anti-reflective coating. This can help reduce glare and improve your viewing experience.
• Take regular breaks from looking at the screen. Every 20 minutes, try to look away from the screen and focus on an object at least 20 feet away for at least 20 seconds. This is known as the "20-20-20 rule" and can help reduce eye strain and fatigue.
• Consider using a blue light filter on your screen. Blue light is known to cause eye strain and can affect your sleep. Many devices have built-in blue light filters that you can enable in the settings, or you can purchase a physical filter that attaches to your screen.
• If you wear glasses, make sure your prescription is up to date. Outdated prescriptions can contribute to eye strain and headaches.
• Finally, don't forget to blink! When we look at screens, our blink rate tends to decrease, which can lead to dry eyes and eye strain. Make a conscious effort to blink regularly to keep your eyes lubricated.

Headaches and eye strain

LCD screens can cause digital eye strain, which in turn can lead to headaches. When looking at a screen, our blink rate drops, causing eye strain. This can be addressed by consciously blinking more often, as blinking keeps the eyes lubricated.

Another way to address digital eye strain is by following the "20-20-20 Rule". Every 20 minutes, look at something at least 20 feet away for at least 20 seconds. This exercise engages your distance vision and gives your eyes a break from focusing on a screen.

LCD screens are not the only culprits when it comes to eye strain and headaches. LED screens, which are more common in 2023, also emit blue light and can cause eye strain and other negative effects. However, LED screens usually offer more robust dimming options and screen comfort tweaks, which can help reduce eye strain.

OLED screens, which are becoming more prevalent, have been described as "extremely unhealthy for the eyes" by some users, causing tired eyes, burning eyes, and general fatigue. OLED screens require the display to be at 100% brightness to eliminate PWM (pulse-width modulation), which causes flicker and leads to eye strain and headaches.

To reduce the negative impact of blue light from screens, it is recommended to reduce screen time, use software that reduces blue light, and wear blue light-blocking glasses.

Can LCD monitors cause permanent eye damage?

LCD screens emit blue light, which is the highest energy wavelength of visible light. This blue light penetrates all the way to the back of the eye, through the eyes' natural filters. The amount of blue light exposure we receive 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 age-related macular degeneration.

LCD screens can also cause digital eye strain. When we look at a screen, our blink rate drops significantly, causing digital eye strain. Symptoms of digital eye strain include slightly blurry vision, headaches, and dry or tired eyes.

However, there is no evidence that LCD screens are worse for your eyes than LED screens. In fact, LED screens may be worse, as they emit more harmful blue light than LCDs.

To protect your eyes, you can try to minimise your usage of LCD screens by reading print media or using E Ink displays instead. You can also try the "20-20-20 Rule", where every 20 minutes, you stare at something at least 20 feet away for at least 20 seconds. This exercise engages your distance vision and allows your eyes to rest. Additionally, you can wear blue light glasses, which minimise the amount of blue light you absorb.

Frequently asked questions