The Effects of Blue Light


Olivia Myers

Composed of electromagnetic particles that travel in waves and emit energy, light wavelengths are placed in the following categories by the electromagnetic spectrum: radio waves, microwaves, infrared radiation, visible light, ultraviolet, x-rays, gamma rays. While each of these groups play an integral role in daily life, the human eye can only comprehend visible light which is seen as colors. However, not all colors on the visible electromagnetic spectrum expel the same frequencies and energy levels. While red light produces long, slow wavelengths that exhibits low energy, blue light gives off short, rapid wavelengths that expel larger amounts of energy, emphasizing the inverse relationship between wavelengths and energy levels. Blue light is most prominently found in natural sunlight, commonly referred to as white light, but blue light also comes from artificial sources such as LED lights, televisions, and smartphones. 


Benefits of Blue Light:

Although blue light is oftentimes regarded in a negative connotation, it also offers influential benefits depending on its period of use. Because blue light helps stimulate cognitive functions (like attentiveness and memory), boosts mood, and improves reaction times, it is most positively influential in doses throughout the day. 


Blue Light at Night:

Blue light heralds negative effects when it is consumed at night or in excess throughout the day. This high energy emitting light plays an integral role in establishing the circadian rhythm which runs on a 24-hour clock. These rhythms, frequently referred to as sleep-wake cycles, regulate integral body processes including hormonal and digestive activities. Because bodies recognize blue light to be a cognitive stimulant, blue light exposure at night can delay and even block the proper production of melatonin, a hormone that regulates the sleep-wake cycle by inducing sleep, which inhibits the body clock from functioning properly. 

Additional health malfunctions relating to nervous and cardiovascular health can result from a lack of sleep, emphasizing the importance of maintaining a balanced circadian rhythm. Excessive use of blue light, specifically from screen time, can impair optimal eyesight as the harshness of blue light can lead to digital eye strain and can harm light sensitive cells in the retina.


THS Students and Blue Light: 


Protective Measures: 

Night Mode on iPhones- Many Apple iPhone users have night mode and dark mode features programmed into their phone. In night mode, the individual’s screen brightness diminishes at a scheduled time before bed and takes on a warmer hue. Because red light emits low energy due to its long, infrequent wavelengths, red light is one of the most optimal colors to consume at night to diminish the harmful effects of blue light as it will stimulate and strain the brain and eyes, respectively, the least. During the day, Apple users can consider setting their phone on dark mode as it changes the bright white screen that can be too harsh on the eyes to a black background.

Blue Light Protecting Apps- Additionally, the app store provides multiple apps that act as a blue light filter on phones; these apps have similar characteristics of the night mode feature as it works to warm the screen, diminishing the harshness of blue light. However, while these filters are helpful, they do not entirely protect users from blue light. 

Blue Light Glasses- Currently a growing trend in a screen-filled world, blue light glasses have specially crafted lenses that help filter out the harsh blue light that electronic screens emit. While many have seen encouraging results from the use of blue light glasses including decreased headaches and a more restless sleep, the relatively new technological discovery of blue light glasses possesses limited scientific research supporting its effectiveness. Many scientists encourage screen users to strive to decrease screen exposure at night to ensure influential results.

20-20-20 Rule- To further reduce any harmful effects from screen use, optometrists have established the 20-20-20 rule which encourages users “every 20 minutes, take a 20-second break and focus [their] eyes on something at least 20 feet away” (SCL Health). This rule reminds avid screen users to give their eyes a break from staring at harsh screens all day which will discourage potential health impairments.

Avoid screens- Although there are some helpful features that can reduce the negative effects of blue light, the soundproof and lightproof course to embrace in an effort to prevent any health impairments from screen use is defined through reducing the time, especially before bed, that individuals spend on technologies. According to SCL Health, screen users should avoid screens at least 30 minutes before going to bed, but many encourage individuals to set their screens aside at least an hour prior to bedtime to ensure a peaceful night of sleep. 





Works Cited:

Publishing, Harvard Health. “Blue Light Has a Dark Side.” Harvard Health, 


“Should You Be Worried About Blue Light?” American Academy of Ophthalmology, 18 Oct. 2018, 


“Why It’s Time to Ditch the Phone Before Bed.” SCL Health,