Blue light is part of visible light, the region of the electromagnetic spectrum that the human eye can perceive. It is emitted by natural sources such as the sun and artificial sources such as electronic devices. Thus, 25% of white light is blue, a natural and necessary component of light whose wavelength is between approximately 380 nm and 475 nm (i.e., the lowest part of the light spectrum).
Visible light is composed of rays of different colors, blue being one of them. The wavelength of each beam that makes up the visible spectrum is different, with infrared being the most prolonged and ultraviolet the shortest. The colors we perceive result from the reflection of a wavelength on a surface and the absorption of the rest. In other words, if we see a red object, it is because its surface reflects the wavelength of the red color and absorbs the different colors.
When visible light passes through a prism, it decomposes, showing the different rays of which it is composed. Rainbows are an example of refraction of the visible spectrum.
Almost all visible blue light passes through the cornea and lens and reaches the retina. This light can affect vision and prematurely age the eyes. Previous research shows that excessive exposure to blue light can lead to:
Digital Eye Fatigue: Blue light from digital device screens can decrease contrast, leading to digital eye fatigue. Fatigue, dry eyes, poor lighting, or the way you sit in front of your computer can also cause eye fatigue. Symptoms of eye fatigue include sore or irritated eyes and difficulty concentrating.
Retinal injury: Studies suggest that continued exposure to blue light over time can cause damage to retinal cells. This can cause age-related macular degeneration (AMD), among other visual problems.
Visible light passes through the lens to the retina, where photoreceptors convert it into an electrochemical signal. Humans depend on this process for image formation and the daily regulation of sleep-wake cycles. Light emitted by the sun and by digital devices contains significant amounts of blue light energy wavelength. (3)
Ultraviolet (UV) light contains more energy than blue light but is absorbed by the cornea and lens, limiting exposure to the retina.
Visible blue light can be potentially harmful to the retina, as it can be absorbed by the pigment epithelium and specific photoreceptors, generating oxidative substances and heat stress. Laboratory studies on rodent and primate models have shown that periods of direct retinal exposure to bright blue light accelerate mortality rates of the pigment epithelium and photoreceptors. (4,5).
Face it. Children will not stop using modern technology. However, there are some easy things you can do to decrease your child’s risk of eye and vision problems due to prolonged use of computers and digital devices.
One of the best things you can do to reduce your children’s risk of digital eye strain is to have them follow the “20-20-20” rule: every 20 minutes, take your eyes off the screen and, for at least 20 seconds, look at something at least 20 feet away.
The experts at blue light kids glasses say it’s wise to protect your child’s eye from both blue sunlight and blue light from digital devices. Glasses with a built-in blue light filter, such as blue light kids glasses, are a good choice for indoor use. Keep in mind that different eyeglass lens companies may measure blue light filtering properties differently, and lenses with the most effective blue light filters carry a tint that will affect their appearance. Finally, certain anti-reflective coatings can help eyeglass lenses filter out blue light.