The amount of “screen time” a typical human gets can be devastatingly high. My day starts with me taking a look at the phone notifications and then getting sucked into the appverse blackhole. If and when my wife manages to pull me out of it, I again face the monster screen, this time in the form of an iPad (or TV sometimes) in order to get my daughter to have breakfast before she rushes to school. At office, I’m completely engaged on my MacBook Pro with intermittent distractions from the phone notifications. Once back home, with ongoing cricket season, I’m glued to the TV before being forced to bed where I try to wrap up the day by clearing the pending phone notifications.

why we need to turn off the blue light - blue light filter

Nomophobia is well and truly real.

While I might be inching towards one extreme end of “screen time”, I’m sure a lot of people would fit in this scale of high screen time in their day-to-day lives. Other than the obvious ‘addiction’ issue, high screen time can be detrimental to our eye health.

What is Blue light or HEV (High Energy Violet) Light?

Please bear with me as I take you back to your primary grade Physics, where you were taught that Light is made up of different colors. The sunlight primarily consists of red, orange, yellow, green and blue light rays and many shades of each of these colors. Combined, this spectrum is what we refer to as white light or sunlight.

why we need to turn off the blue light - blue light hev

There is an inverse relationship between the wavelength of light rays and the amount of energy they contain. Light rays that have relatively longer wavelengths contain lesser energy, and those with shorter wavelengths have more energy. Rays on the red end of the visible light spectrum have longer wavelengths and, therefore, less energy. Rays on the blue end of the spectrum have shorter wavelengths and more energy.

Blue light generally is defined as visible light ranging from 380 to 500 nm. So, approximately, one-third of all visible light is considered high-energy visible (HEV) or “blue” light. In short, the visible blue light has shorter wavelengths and higher energy.

And to be clear, the blue light is everywhere. From sunlight to fluorescent/LED lights to all kinds of TVs to computers/tablets/smartphones, the Blue light is literally everywhere. While the amount of blue light emitted by these devices is only a fraction as compared to the sunlight, the amount of time we end up using these devices is growing higher by the day.

Is Blue light harmful?

Yes and No. Some researches have shown that HEV light boosts alertness, helps memory and cognitive function and elevate mood. And blue light is very important in regulating circadian rhythm — the body’s natural wakefulness and sleep cycle.

But too much of blue light, especially at night, can disrupt circadian rhythm, potentially causing sleepless nights and daytime fatigue. While studies have proved that UV (ultraviolet rays), which have even shorter wavelength (and hence higher energy) than HEV light, can cause damage to both the front and the back of the eye, there are some indications that HEV can cause similar issues with human eyes.

why we need to turn off the blue light - blue light eyes

Although the front of the human eye is known to be effective at blocking UV rays from reaching the light-sensitive retina at the back of the eyeball, virtually all visible blue light passes through the cornea and lens and reaches the retina. This is why many ophthalmologists warn that too much exposure to blue light can damage light-sensitive cells in the retina.

Do computer screens emit blue light?

Yes. And that’s true with all kinds of screens – smartphones, tablets, televisions, smart displays, etc. As I mentioned earlier, blue light has a shorter wavelength and hence flicker more easily. This kind of flickering creates a glare that can reduce visual contrast and affect sharpness and clarity.

How to avoid Blue light?

As mentioned earlier, Blue light or HEV light has both good and bad effects on the human body. While humans have managed just fine for millions of years without having to worry about the blue light which is primarily emitted by the sun, the understanding is that was possible because humans didn’t have access to artificial sources of blue light emission like we do now. While keeping away from digital screens is virtually impossible, there are some ways to reduce our exposure to blue light.

(a) Software/apps

why we need to turn off the blue light - night shift

Thanks to increasing awareness, technology companies have started adding specialized modes to reduce blue light/ HEV on digital screens.

  • Apple has added Night Shift feature on iOS which automatically adjusts the colors of your display to the warmer end of the spectrum — making the display easier on your eyes. You can also use Night Shift on MacOS devices. Alternatively, Mac users can also use apps like Flux.
  • With Oreo, Google decided to integrate the night mode on Android. To activate it, just go to Settings > Display > Night Light. You can also configure it so that Night Light will turn off automatically at certain times. Individual smartphone OEMs like OnePlus, Huawei and others have their own implementation as well. Just look for “Reading mode” or “night mode” in your settings menu.
  • On Windows 10, Microsoft has added a dedicated “Night Light” feature which can be enabled as explained in this article.

While it’s a significant step in the right direction, these software solutions don’t efficiently block all blue light. While any reduction in the intensity or duration of blue light is helpful, it’s important that people look to other means to protect their baby blues.

(b) Eye comfort certified screens

why we need to turn off the blue light - tuv certified screens

Not just the software developers, even the hardware developers are waking up to the increased awareness about blue light hazards. Organizations like TÜV Rheinland certify digital screens specifically for ‘Eye comfort’. For example, some of the recent Super AMOLED screens from Samsung are TUV certified for eye comfort. Similarly, Huawei/Honor has got some of their phone displays certified for Blue light reduction. While these displays will still continue to emit blue light, they are certified to be ‘safer’ as compared to regular displays.

(c) Eyeglasses

why we need to turn off the blue light - blue light glasses

The most comprehensive and obvious way to avoid the possible harm from blue light is to wear blue light blocking glasses. As we mentioned earlier, the sun is the biggest emitter of blue light. While we can take care (to an extent) of digital screens through apps and use of TUV-certified screens, wearing blue-light blocking glasses can be more beneficial especially during the day and outdoors.

A low-priced option is to wear glasses with orange-red tint but they can be annoying to use regularly. Other than that, anti-reflective coatings such as Crizal Prevencia can block about 20% of HEV. These can be put on most types of prescription lenses. Also, some companies sell a lens material called UV++ which blocks well over 90% of HEV. Recently, I tested BluMax glasses from Nova Eyewear which helps to protect from harmful UV rays & high energy Blue Light. They are available in a wide range of prescriptions.

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