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  • Nicole Chu and Tanya Li

Blue light from technology: Is it harmful?

A person is exposed to blue light everywhere; however, with a change to more virtual work, many students have been increasing their screen time to accommodate online learning. This brings up the issue of blue light exposure and its impact on one’s eyesight and sleep quality. Before diving into these problems, we must first explore what blue light is and where it originates from.

Blue light is a form of visible light with a wavelength between 400 and 450 nanometers (nm) (Nostalgic Eye Care, 2020). Blue light rays contain one of the shortest wavelengths on the visual spectrum of electromagnetic radiation. Since there is an inverse relationship between wavelength and energy, blue light contains one of the highest energies.

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It is a common misconception to think that blue light is only emitted from the screen of a device, but in reality, the largest source of blue light is actually the sun. In fact, in small amounts, exposure to natural blue light presents many positive effects - such as boosting mood, memory and cognitive function (Harvard Health…, 2020). Consumer electronics present the largest source of artificial blue light exposure. It is also the source of blue light that one is most frequently exposed to after sundown. Even though these devices only emit a fraction of blue light from the sun, the amount of time people spend on their electronics can cause bluelight to be dangerous.

The negative impact of blue light is quite well known, including risk of macular degeneration and digital eye strain. Since the eye cannot protect itself from blue light, blue light can penetrate the eye all the way until the retina; damaging the light-sensitive photoreceptors in the eye. This can increase the risk of macular degeneration in the future, causing potential blindness. Moreover, the blue light from screens is high energy, and scatters more easily than other visible light. Therefore, for students staring at one screen for long hours, blue light can contribute to headaches and mental fatigue.

Apart from the impacts on the eye, blue light can also influence sleeping patterns. Blue light can suppress the secretion of melatonin and can impact the body’s internal biological clock which regulates the circadian rhythm. In fact, a Harvard 2010 study compared the effects of 6.5 hours of exposure to blue light to exposure to green light demonstrated that blue light suppresses melatonin for about twice as long as the green light, and shifted circadian rhythms twice as much (3 hours vs. 1.5 hours) (Harvard Health…, 2020).

For many students, university has shifted to be completely virtual, forcing many to rely more on digital devices to complete all assignments and lectures. This increases the length of time spent on devices; and presents the issue of digital eye strain. How can we protect our vision if the dependency on technology has increased?

Tune into our podcast Healthcare: Signs and Symptoms after reading this to hear new opinions on this topic.


Nostalgic Eye Care. (2020). What is Blue Light?. Retrieved Oct 27, 2020.

Harvard Health Publishing: Blue light has a dark side. (July 7, 2020). Harvard Medical School. Retrieved Oct 28, 2020.


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