Blue Light: A deep dive into its effects and how to protect yourself

macbook pro beside white ipad

Blue light is an interesting topic these days, particularly due to the growing time we spend on digital devices. It has both benefits and drawbacks, and it’s essential to understand how it affects us, especially when it comes to our neurological system and eye health.

What is Blue Light?

Blue light is a type of visible light with wavelengths between 400 and 500 nanometers (nm). It is all around us, coming from natural sources like sunlight, as well as artificial sources like computer screens, smartphones, and office lighting. Blue light is a high-energy form of visible light, closer to ultraviolet (UV) light in the light spectrum.

Blue Light: Day vs. Night

Daytime: During the day, blue light is an important component of sunlight that reaches us. It helps regulate our circadian rhythm, our biological clock that determines our sleep-wake pattern. It also stimulates the production of cortisol, a hormone that keeps us awake and alert.

After Sunset: After sunset, natural light levels decrease, along with the amount of blue light from the sun. This signals our brains to produce melatonin, a hormone that helps us relax and prepares us for sleep. However, continuous exposure to blue light from digital devices and office lighting can disrupt this natural cycle, leading to sleep problems.

Effects of blue light on our neurological system and eye health

Sleep problems: One of the biggest issues with blue light from digital devices and office lighting is its disruption of our circadian rhythm. By suppressing melatonin production, blue light can cause sleep problems such as insomnia or a disrupted sleep cycle. This can lead to fatigue, irritability, and reduced concentration.

Cognitive performance: Poor sleep can directly affect our cognitive functions, such as memory, concentration, and learning ability. This can impact not only daily life but also work performance and the ability to study effectively.

Eye health: Blue light from screens can also contribute to digital eye strain, characterized by symptoms such as dry eyes, blurred vision, and headaches. Long-term exposure can also contribute to more serious conditions such as macular degeneration, which affects the central vision of the eye.

Yellow and red glasses: pros and cons

Yellow Glasses:

  • Pros: Yellow glasses are designed to filter out blue light between 400 and 500 nm, which can help reduce digital eye strain and sleep disruption. They also enhance contrast and visual clarity, which can be useful for working behind a computer screen or reading.
  • Cons: Yellow glasses only filter out part of the light spectrum, meaning they may be less effective at protecting against the full effects of blue light.

Red Glasses:

  • Pros: Red glasses offer a broader range of protection, including some of the green light spectrum (up to about 550 nm). This makes them more effective at blocking both blue and green light, which can help regulate sleep and reduce cognitive and emotional problems.
  • Cons: Red glasses can block more light, which may reduce visual clarity and make it harder to distinguish natural colors.


Dry eyes: Staring at a screen for extended periods can reduce the frequency of blinking, leading to dry eyes. This can cause discomfort, itching, and even blurred vision.

Headaches: Eye strain from focusing on a screen can lead to headaches, particularly tension headaches, which may intensify the longer one uses a digital device.

Blurred vision: The constant effort to focus on a screen can cause the eye muscles to fatigue, resulting in blurred or fluctuating vision. This effect can be more pronounced after several hours of uninterrupted screen time.

Neck and shoulder pain: In addition to direct eye-related symptoms, digital eye strain can lead to poor posture, causing discomfort in the neck, shoulders, and back.


    Duration of screen time: Symptoms of digital eye strain can appear after just 2 to 4 hours of continuous screen use, depending on individual sensitivity and eye health.

    Screen brightness and contrast: High brightness or contrast settings on digital screens can contribute to eye fatigue, making the symptoms appear sooner.

    Viewing distance: Sitting too close or too far from the screen can strain the eyes, worsening the symptoms of digital eye strain.


      1. The 20-20-20 Rule: To alleviate the symptoms of digital eye strain, it’s recommended to take regular breaks following the 20-20-20 rule. Every 20 minutes, look at something 20 feet away for 20 seconds. This helps relax the eye muscles and reduces fatigue.
      2. Adjusting screen settings: Lowering the brightness and increasing the contrast on screens can reduce eye strain. Additionally, using software to filter blue light can further lessen the impact of digital devices.
      3. Proper posture: Ensuring an ergonomic setup for your computer or digital device can help reduce strain on the neck, shoulders, and back, further minimizing discomfort.

      Blue light is a complex phenomenon with both benefits and drawbacks. During the day, it helps keep us alert and awake, but in the evening and at night, it can disrupt our sleep and contribute to neurological and eye health problems. By being mindful of our exposure to blue light, such as reducing screen use in the evening and wearing glasses that filter blue light, we can better protect ourselves and lead a healthier life.