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The Impact of Blue Light on Eye Health

Author: Ella Chen

Editors: Jonathan Chen, Suri Liu

Artist: Alicia Chen


Blue light glasses and blue light screen protectors have been the trend lately, but what exactly is blue light, and why does it matter that we protect our eyes from it? Contrary to popular belief, blue light is emitted not only from digital screens but also from the sun. During the day, the sun’s natural blue light helps boost alertness, raise moods, and improve attention spans. However, excessive exposure to blue light during nighttime harms your eyes and sleep cycle. This is when blue light protection methods come into play.

The visible light spectrum ranges from 400 to 700 nanometers on the electromagnetic spectrum, and we perceive each wavelength as different colors, from red to violet (also known as ROY G BIV). Blue light wavelengths are usually between 400 and 500 nanometers, with wavelengths between 415 and 455 nanometers being the most damaging to the eye. The eye has structures like the cornea and lens to protect it from certain types of light, such as UV rays, but blue light can penetrate through these structures into the retina, where it can potentially cause retinal damage. 

The main way blue light negatively affects individuals is through the use of digital devices. Most of the blue light coming from digital devices has wavelengths between 400 and 490 nanometers, meaning there can be harmful effects to the eye from the overuse of these devices. While there hasn’t been any concrete evidence that blue light exposure leads to long-term consequences to the eyes, such as sight loss, it can still lead to eyestrain and dry eyes, which are harmful for your eyes. Blue light scatters more often than other forms of visible light, which makes it more difficult for the eye to focus on something when exposed to it, contributing to eye strain as the eye needs to do more work to process the blue light. Furthermore, when people use digital devices, they tend to blink less often than usual, decreasing moisture in the eyes and thus leading to dry eyes. Due to these reasons, people often notice symptoms like dry, sore eyes and headaches when using digital devices for prolonged periods of time. To combat the effects of eye strain, it’s important to take breaks from screens and follow the 20-20-20 rule: every 20 minutes, look away from the screen and focus on a non-digital object 20 feet away for at least 20 seconds. Other solutions include sitting at least arm’s length away from the screen, and adjusting screen brightness based on your surroundings. 

If these protective measures are not taken, blue light can affect one’s sleep cycle. It’s hard to resist doing a final scroll on social media before sleeping, but that habit is actually harming the quality of one’s sleep. Since blue light is emitted by the sun during the day, exposure to blue light at night causes the body to believe that it’s still daytime, resulting in the body slowing down the release of the sleep hormone melatonin, making it harder to fall asleep and get a good night’s sleep. To make sure that you are getting good sleep, it’s important to limit screen time before going to bed; it’s recommended to stay away from screens at least an hour before going to bed. This way, melatonin can be secreted as usual. Similarly, turning on the night shift mode function on your device adjusts the screen to a warmer tone, which filters out some blue light, though this lacks scientific evidence. Thus, it’s better to stay away from screens entirely before bed, as that best affects sleep quality. 

There has yet to be scientific evidence that blue light exposure can lead to severe long-term effects on the eye, as research is still ongoing. However, the known effects of blue light should still be considered. In the digital age, the need to protect our eyes is becoming increasingly prevalent, so the necessary preventative measures should be taken. 

 

Citations:

Helmer, Jodi. “What Is Blue Light and Where Does It Come From?” WebMD, 2020,

Stanborough, Rebecca Joy. “What’s Blue Light, and How Does It Affect Our Eyes?”

Zhao, Zhi-Chun, et al. “Research Progress about the Effect and Prevention of Blue Light on

Eyes.” International Journal of Ophthalmology, vol. 11, no. 12, 18 Dec. 2018,

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