Q. My two boys came home from school today saying they heard you talk about “blue light rays from the sun.” Excuse me? Blue light comes from electronics! I told them you are a brain function specialist and can’t be expected to know everything.

A. You are correct. I cannot be expected to know everything. No one can. You only know what you know. That’s the value of “learning.” You increase what you know. Perhaps your brain hasn’t been exposed to information about blue wave light from the sun…. Here is a summary of what I said.

Light is composed of electromagnetic particles that travel the universe in waves, which release energy. Known as the electromagnetic spectrum, there are several categories of light waves: gamma rays, x-rays, ultraviolet (UV) rays, visible light, infrared light, and radio waves. The human eye is sensitive to only one part of this electromagnetic spectrum: visible light. This is the part of the spectrum that is seen in colors: red, orange, yellow, green, blue, indigo, and violet.

One of those wave lengths is blue light and it is everywhere. They’re believed to bethe reason the sky looks blue. When the sun’s rays travel through the atmosphere, the high-energy blue waves crash into the air molecules, scattering blue light everywhere. Blue light from the sun helps you feel alert, in a pleasant mood, and regulates your circadian rhythm. When you are outside you can be exposed to blue light wherever the sun’s rays can reach you. Studies suggest that exposure to the blue end of the visible light spectrum could cause serious long-term damage to a person’s eyes. However, human eyes can be exposed indoors, as well. Humans are now exposed to a great deal of artificial blue light from electronic sources, because many devices emit blue light. Like cell phones, television, laptop computers and tablets, as well as energy-efficient LED lights and fluorescent bulbs.

Blue wave light, often called High Energy Visible (HEV) wavelengths flicker more easily than longer, weaker wavelengths. Blue-wave flickering creates a glare that can reduce visual contrast and affect sharpness and clarity. Some believe this may contribute to eyestrain, physical and mental fatigue, and even headaches, especially if a person spends hours and hours being exposed to blue waves. In addition, prolonged exposure to blue light may cause damage to the retina and increase the risk of age-related macular degeneration, which can lead to loss of vision. According to David Brownstein, MD, the photoreceptor cells in the retina display the highest rate of oxidation of all cells in the body. Researchers have linked exposure to blue light at night (e.g., working the night shift) to an increased risk for diabetes, heart disease, obesity, some types of cancer, diabetes, heart disease, and an increased risk for depression. This may be because blue light can suppress the production of melatonin.

Researchers say that filters in human eye such as the cornea and the lens do a good job of blocking ultraviolet rays from reaching the light-sensitive retina at the back of the eye. Those filters do not block natural or artificial blue light from reaching the retina. Studies have shown that exposing your eyes to a digital device for even two consecutive hours can cause eyestrain and fatigue. Some are recommending that technology users wear special blue-light blocking glasses or screen protectors when using electronic devices. And everyone is wise to wear sunglasses when out in bright sun.