February 9, 2024

Does Blue Light Really Affect Your Eyes?

Written by our expert


Avanthika Nityanand

M.Sc Human Genetics, B.Sc Plant Biology & Plant Biotechnology

Does Blue Light Really Affect Your Eyes?
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Did You Know? Macular pigments like lutein and zeaxanthin can naturally filter blue light.

What is a Blue Screen Light?

Blue screen light, or blue light, is part of the visible spectrum emitted by the sun, digital screens (such as computers, smartphones, and televisions), and artificial lighting.

It has a short wavelength, meaning it is higher in energy than other types of light in the visible spectrum.

Blue light is everywhere.

While it is beneficial during daylight hours as it boosts attention, reaction times, and mood, excessive exposure to blue light, especially after sunset, is a growing concern due to potential impacts on health, particularly eye strain, and disruption to the circadian rhythm.

Blue Screen Light

Is Blue Screen Light Bad for Your Eyes?

Excessive exposure to blue light, especially from screens, can lead to digital eye strain, causing symptoms like dry eyes, irritation, difficulty focusing, and headaches.

Over time, there's concern that prolonged exposure to high-energy visible (HEV) blue light could damage retinal cells, potentially increasing the risk of macular degeneration, though more research is needed to understand the long-term effects fully.

While blue light is a natural part of the visible light spectrum and not inherently bad, moderation and protective measures are advised, especially during prolonged screen use.

A 2016 study observed that LEDs emitting light around 470–480 nm are preferable over those below 450 nm. Short to medium-term exposure to blue light in the 470–480 nm range is believed not to significantly heighten the risk of ocular diseases, but the impact of long-term exposure remains uncertain. Further research is necessary to assess the safety of prolonged exposure to low levels of blue light and its effects on eye health. [ref]

Do Blue Light Screen Protectors Work?

Blue light screen protectors or anti-blue light screens are designed to filter out a portion of the blue light emitted by digital screens.

They are thought to reduce the potential negative effects on sleep patterns and decrease eye strain.

These protectors typically use a physical filter or a coating that reflects or absorbs blue light.

While they can effectively reduce the amount of blue light reaching the eyes, their efficacy varies by product.

Some users report a noticeable reduction in eye strain and improvement in sleep quality, while others may not notice as significant an impact.

Choosing a high-quality blue light filter and combining it with other eye care practices can enhance its effectiveness.

A study published in April last year (2023) showed that protective measures like blue-blocking lenses have not shown evidence of preventing eye diseases like age-related macular degeneration (AMD). Instead, the study suggests that natural protection comes from macular pigments, such as lutein and zeaxanthin, which filter blue light. These compounds can be boosted through diet or supplements, potentially reducing AMD and cataract risks. [ref]

Another systematic review of 17 randomized controlled trials published in August last year (2023) involving 619 adults compared blue-light filtering lenses to non-blue-light filtering lenses. The results showed that the impact on subjective sleep quality was inconclusive, with only half of the studies (3 out of 6) reporting an improvement. Additionally, there appeared to be no significant effect of blue-light filtering lenses on visual fatigue, as observed in three studies. There was also no noticeable impact on daytime alertness and visual acuity. [ref]

Does Blue Light Affect Your Sleep?

A 2022 systematic review aimed to consolidate current evidence on the effects of blue light exposure from electronic devices on sleep, performance, and well-being, with a focus on its significance for athletes. The findings indicate mixed effects of blue light exposure: 50% of the studies reported a decrease in tiredness, while impacts on sleep were generally negative, with decreases in sleep quality, duration, and efficacy and an increase in sleep latency. [ref]

A 2023 study showed that decreasing blue light emission from mobile phones at night can significantly improve subjective sleep quality, daytime functioning, and ease of falling asleep among students. [ref]

Do Privacy Screens Block Blue Light?

Privacy screens are primarily designed to limit the viewing angle of a screen, protecting information from being seen by others around you.

While their main function is not to block blue light, some privacy screens have an added feature of blue light filtering.

The extent to which they block blue light depends on the specific product and technology.

It's important to check the product specifications to understand its blue light-blocking capabilities.

Does a Black Screen Emit Blue Light?

A black screen, or when a screen is turned off, does not emit visible light, including blue light.

However, when displaying black content while the screen is on, it may still emit a small amount of blue light, depending on the technology of the screen.

OLED screens, for instance, can turn off individual pixels to display true black, emitting no light in those areas.

In contrast, LCD screens use a backlight for the entire screen, which means even black areas may emit some light, potentially including blue light, though at reduced levels compared to brighter colors.

Do TV Screens Emit Blue Light?

Yes, TV screens, like other digital screens, emit blue light due to the LED technology used in most modern displays.

The amount of blue light emitted can vary depending on the type of screen and the settings used.

While TV viewing typically occurs at a greater distance than other devices, which can reduce strain, prolonged exposure, especially before bedtime, can still impact sleep patterns.

This is attributed to the effect of blue light on melatonin production. [ref]

How to Block Blue Light from Computer Screen

Blocking blue light from a computer screen can be achieved through several methods:

  1. Software Solutions: Many computers and operating systems now have built-in settings to reduce blue light emissions, such as Night Shift on macOS or Night Light on Windows. These settings adjust the screen's color temperature to warmer tones, reducing blue light, especially during evening hours.
  2. Blue Light Filtering Software: Some third-party applications can provide more customizable control over the amount of blue light your screen emits based on the time of day.
  3. Physical Blue Light Filters: Applying a physical blue light filter or using a monitor with built-in blue light reduction technology can also be effective.

Can Diet Play A Role In Filtering Blue Light?

Certain nutrients bolster the eye's ability to protect against blue light and its potentially harmful effects.

Key among these nutrients are lutein and zeaxanthin, two types of carotenoids found in high concentrations in the eye macula, acting as natural blue light filters. [ref]

By absorbing blue light, they can help protect the eyes from damage that could lead to digital eye strain and contribute to the risk of developing AMD.

Foods rich in lutein and zeaxanthin include leafy greens (such as spinach, kale, and collard greens), peas, egg yolks, and corn.

Omega-3 fatty acids, found in fish like salmon, sardines, and flaxseeds, are also beneficial for eye health and may support the eyes' natural ability to combat the negative effects of blue light.

Furthermore, vitamins C and E have antioxidant properties that can help protect the eyes from oxidative stress caused by exposure to blue light.

These vitamins can be found in citrus fruits, berries, nuts, and seeds.

Incorporating these nutrients into your diet can support the health of your eyes and may enhance their natural defenses against blue light.

However, it's also important to balance dietary efforts with other protective strategies, such as using screen filters, taking regular breaks from screens, and using artificial lighting that minimizes blue light exposure, especially before bedtime.

How to Reduce Blue Light from Computer Screen

Reducing blue light from a computer screen can involve adjusting the display settings or using accessories:

  1. Adjust Display Settings: Lowering the brightness and changing the display to a warmer color temperature can reduce blue light exposure.
  2. Use built-in software features: Utilize features like night shifts or night lights to adjust the color temperature automatically in the evenings.
  3. Install Third-party Applications: Programs like f.lux adjust your screen's color temperature according to the time of day, reducing blue light in the evening.
  4. Wear Blue Light Blocking Glasses: These glasses can filter out blue light and are especially useful for multiple devices.

How to Turn Off Blue Light on Computer Screen

Turning off the blue light on a computer screen can be effectively managed through the device's built-in settings or third-party applications:

  1. Built-in Settings: Access the display settings on your computer to activate Night Light (Windows) or Night Shift (macOS), which reduces blue light by adjusting the screen's color temperature.
  2. Third-party Applications: Install applications like f.lux, which offer customizable settings for reducing blue light based on location and time of day.

Does Blue Light Have Any Health Benefits?

A 2022 systematic review showed that blue light positively impacted cognitive performance, alertness, and reaction times. This potentially benefits athletes in sports requiring teamwork, quick decision-making, and possibly aiding in injury prevention. However, more research is needed to explore these aspects. [ref]

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