Everything you should know about blue light

It is reported that on an average a person spends more than 8 hrs on phone in a day and roughly around 11 hrs on screen. The global reports have predicted that the number of smartphones users is about to grow more than 5 billion smartphones in 2019. All the screen time you are spending is taking a toll on your eyes, yes we are talking about the blue light which are emitted by the devices.

In this article “Everything you should know about blue light”, we will go through a discussion of what is blue light? is it really harmful? how can we protect ourselves from it?

What is Blue light?

first what is light? light is basically a electromagnetic waves which our eyes can detect it’s frequencies ranging between 430 – 770 THz and wavelength of 380 – 740 nanometers. this spectrum which our eyes can detect is also called as visible spectrum or visible light. this spectrum does not contain all the lights that we can see for eg it does not contain pink, purple, magenta color, these colors are made by humans by mixing different colors.

sunlight is white in color which is the mix of all the colors in the spectrum. white light contains red, blue and green and all the shades of the color. all these visible colors have certain amount of energy. A wave having large wavelength will have less energy and a wave having shorter wavelength will have great energy associated with it.

visible spectrum of electromagnetic waves
visible spectrum courtesy: All About Vision

Rays on the red end of the spectrum have large wavelength and hence less energy and rays on the purple end of the spectrum have shorter wavelength hence having more energy. the electromagnetic wave just beyond the visible light are called as UV (Ultra Violet rays).

One third of all the visible light is called as the blue light. blue having a less wavelength is the same reason we see the sky blue, but sky can be other colors too, but we cannot see it through our eyes, how interesting that is!

what effects it could cause?

1.) Exposure to blue light could cost you your sleep.

Blue light does mess up with the circadian rhythms of the body. It is advised you do not spend screen time 2 hrs prior to your sleep. It preserves the hormone melatonin to release which are essential for your sleep and maintaining your circadian rhythm.

In a study conducted by the University of Toronto, it was found that people exposed to blue light have their melatonin suppressed that those without blue light exposure.

It also played badly with their circadian rhythm. It is suggested you to avoid night shift and if not possible wear a blue light filter glasses.


2.) Blue light contributes to digital eye strain

staring at computer screens and mobile devices for too long will cause strain in your eyes, since blue light is having low wavelength hence get scattered more easily in your eyes and causes strain in your eyes because it does not focus at particular point.

picture of an eye digitally strained
digital eye strain courtesy: the Nib

If you recently had a cataract surgery it is necessary to protect yourself from the UV light. our eyes is good at blocking Ultra Violet rays but it cannot protect us from blue light that comes from other artificial light emitting sources.

3.) Blue light damages your retina

blue light damages your retina which can sauce temporary / permanent blindness. blue light enters deep into eyes and damages your retina which is responsible for detecting the light. the cells which are present are continuously getting burned down due to exposure of the light. In studies it is concluded that these cells cannot be regenerated.

blue light entering from screen into the eye
Everything to know about blue light. courtesy: wixtech.tw

4.) Exposure to blue light may lead to macular degeneration

the fact that blue light penetrates deep in the eye, in the lining of the retina which contains light sensitive lights. these cells when damaged by long exposure to blue light can lead to permanent loss of vision and also a condition called as macular degeneration.

How to protect yourself from blue light.

1.) Dim red light

when working late at night use dim red light of the screen, it will not suppress melatonin, shift circadian rhythm.

2.) Avoid exposure

avoid exposure 2 – 3 hrs prior going to sleep to bright light and blue light.

3.) use blue light filtering glasses

if you are doing night shift use blue light filtering glasses and apps which block the blue light to enter your eyes. most of the android and Apple devices come with reading mode / blue light mode etc.

night mode, reading mode demo of google play book
night mode, reading mode demo of google play book

4.) change your workplace lighting condition

changing your workplace lighting condition will definitely help as you will be spending most of your time in your place. Improve the lighting conditions, use bright colors for day and light and reddish, yellow color for the night.

All are blue light harmful?

it is found that some exposure to blue light is essential for humans, it keeps them alert and help memory and cognitive functions to work properly. It is also important component in maintaining your natural circadian rhythm, your natural sleep, wake patterns are all formed by the exposure to blue light, but too much exposure will definitely disrupt that cycle.

Hope you picked up some good clues of how to protect your eyes.

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