What is Blue Light

Light is made up of electromagnetic particles that travel in waves.  These waves emit energy, and range in length and strength. The shorter the wavelength; the higher the energy. The length of the waves is measured in nanometers (nm), with 1 nanometer equaling 1 billionth of a meter.  Every wavelength is represented by a different colour, and is grouped into the following categories: gamma rays, x-rays, ultraviolet (UV) rays, visible light, infrared light, and radio waves.  Together these wavelengths make up the electromagnetic spectrum.

However the human eye is sensitive to only one part of this spectrum: visible light. Visible light is that part of the electromagnetic spectrum that is seen as colours: violet, indigo, blue, green, yellow, orange and red.  Blue light has a very short wavelength, and so produces a higher amount of energy. Studies suggest that, over time, exposure to the blue end of the light spectrum could cause serious long-term damage to your eyes.


Blue light has a wavelength of between approximately 380nm and 500nm; making it one of the shortest, highest-energy wavelengths.

Where is Blue Light Found?

Sources of blue light include the sun, digital screens (TVs, computers, laptops, smart phones and tablets), electronic devices, and fluorescent and LED lighting.

Natural blue light versus artificial blue light

Blue light is actually everywhere. When outside, light from the sun travels through the atmosphere. The shorter, high energy blue wavelengths collide with the air molecules causing blue light to scatter everywhere.  This is what makes the sky look blue. In its natural form, your body uses blue light from the sun to regulate your natural sleep and wake cycles.  This is known as your circadian rhythm.  Blue light also helps boost alertness, heighten reaction times, elevate moods, and increase the feeling of well being. Artificial sources of blue light include electronic devices such as cell phones and laptop computers, as well as energy-efficient fluorescent bulbs and LED lights.

Why should we be concerned about blue light exposure?

Blue light waves are the among the shortest, highest energy wavelengths in the visible light spectrum.  Because they are shorter, these "Blue" or High Energy Visible (HEV) wavelengths flicker more easily than longer, weaker wavelengths. This kind of flickering creates a glare that can reduce visual contrast and affect sharpness and clarity. 

This flickering and glaring may be one of the reasons for eyestrain, headaches, physical and mental fatigue caused by many hours sitting in front of a computer screen or other electronic device.  

Our eyes' natural filters do not provide sufficient protection against  blue light rays from the sun, let alone the blue light emanating from these devices or from blue light emitted from fluorescent-light tubes. Prolonged exposure to blue light may cause retinal damage and contribute to age-related macular degeneration, which can lead to loss of vision.

Where is the increased exposure to Blue Light coming from?

The evolution in digital screen technology has advanced dramatically over the years, and many of today's electronic devices use LED back-light technology to help enhance screen brightness and clarity.  These LEDs emit very strong blue light waves.  Cell phones, computers, tablets and flat-screen televisions are just among a few of the devices that use this technology.  Because of their wide-spread use and increasing popularity, we are gradually being exposed to more and more sources of blue light and for longer periods of time.

Sources of blue light include the sun, digital screens (TVs, computers, laptops, smart phones and tablets), electronic devices, and fluorescent and LED lighting.