top of page


Updated: Mar 27

Author: Berci Sirák

Publication date: 19.03.2024

It is a commonly accepted fact that we perceive the world around us through our five senses. Among these senses, vision is the most significant, as it provides a healthy person with approximately 60-80% of the information from the external world. The fact that 40% of the human brain is dedicated to vision further highlights its importance. 

What is blue light?

Blue light is a high-energy visible light that vibrates within the 380 to 500 nanometer range and constitutes approximately one-third of all visible light.   It has numerous benefits, such as enhancing alertness, improving memory and brain function, elevating mood, and regulating the body's circadian rhythm.

Sunlight is the primary source of blue light. Fluorescent light, LED TVs, computer monitors, smartphones and tablet screens are all artificial sources of blue light. Exposure to blue light from these sources can cause eye strain and disrupt sleep patterns. Limiting exposure to blue light before bedtime is recommended to improve sleep quality.

The good effects of blue light

Blue light enhances alertness, memory, and brain function, improves mood, and regulates the body's natural circadian rhythm. Sunlight is crucial for the growth and development of children's eyes and vision. Light, especially blue light that reaches the retina, also affects our psychological well-being. This is why light therapy has been used successfully to treat winter depression and insomnia. However, as is so often the case, "everything in moderation" still applies. Exposure to too much light also carries certain risks and can even be harmful.

The harmful effects of blue light

An excessive amount of UV and blue-violet light might harm an individual's eyes. In addition to producing excruciating inflammation of the cornea and conjunctiva, it can also harm the eye's lens (cataracts, for example) and, most importantly, the retina (macular degeneration).

Because of this, it's crucial to wear sunglasses that offer 100% UV protection when it's really sunny outside, especially in places with a lot of glares like by the sea or on snow-covered mountain slopes.

Blue light against sleep

Your eyes have a limited ability to filter out blue light. So almost all of it goes straight through to the back of your retina, helping your brain to convert light into images.

Your circadian rhythm, which regulates your natural sleep-wake cycle, is supported by exposure to all colours of light. Because it inhibits the sleep-inducing hormone melatonin, blue light disrupts your body's ability to prepare for sleep more than any other colour.

Simple ways to limit blue light exposure

·      20/20/20 strategy

Try to look away from anything 20 feet (~6 meters) away for 20 seconds every 20 minutes that you spend staring at a screen.

·      Adjust the blue light on your screen

You might want to turn your screens to a "night shift" setting with warmer tones to reduce the likelihood of eyestrain and sleep disruption. If you work at night, you can also buy blue-light-filtering screens to put over your computer screen. The screen glare may be reduced by the filter.

·      Cut back screen time

Begin reducing your screen usage two to three hours before bed.


In conclusion, the timing and quantity of exposure to blue light can be both advantageous and detrimental. Even though blue light might make us feel more alert and happier during the day, too much of it, especially at night and in the evening, can make it difficult to fall asleep and strain our eyes. It is imperative to strike a balance in blue light exposure to mitigate potential risks while harnessing its benefits. By adopting mindful habits and employing available technologies to reduce nighttime exposure, individuals can prioritize both eye health and restorative sleep patterns.


You can also read about:


Reference list:

33 views0 comments


bottom of page