Blue light is a short-wavelength light generally defined as visible light ranging from 380 to 500 nm (nm – nanometers) in the light spectrum, which is known as high-energy visible blue light (HEV).  Blue light sometimes is further broken down into blue-violet light (roughly 380 to 450 nm) and blue-turquoise light (roughly 450 to 500 nm).  The blue-violet light is the one we need to avoid.

The high-energy visible blue light has been singled out as more significantly disruptive to sleep than any other color on the light spectrum.  It suppresses the release of melatonin, disrupts circadian rhythms, and may influence mood changes negatively. Circadian disruption produces serious effects including an increase in obesity and depression.

As a result of our long exposure to artificial blue light, we have eye fatigue, dry eyes, blurred vision, and even headaches. These are symptoms of digital eye strain. Prolonged exposure to artificial blue light has been found to damage the retina, the part of the eye that keeps objects in focus.

Recent studies also suggest that exposure to the blue end of the light spectrum over a sustained period can also contribute to long term vision issues such as cataracts, retinal damage and possibly lead to age-related macular degeneration (AMD).

Blue light is also considered a “carcinogenic pollution” that in mice correlates with higher cancer rates.  A study links night exposure to blue light with breast and prostate cancer.