OccuSafe Industrial Hygiene Consulting

Although it is environmentally friendly, blue light can affect your sleep and potentially cause disease. Until the advent of artificial lighting, the sun was the major source of lighting and people spent their evenings in relative darkness. Now, evenings are illuminated, and we take our access to artificial lighting for granted.

Blue light is part of the electro-magnetic spectrum between 415 and 455 nanometers (nm). Exposure to blue light can have beneficial effects but in large amounts, especially at night, can affect sleep. Exposure to blue light at night throws the body’s biological clock, the circadian rhythm, out of whack and sleep suffers. Furthermore, has shown that it may contribute to the cancer, diabetes, heart disease, and obesity. Studies in animal and cell cultures have shown that wavelengths in the blue portion of the electro-magnetic spectrum (400–500 nm) can induce retinal damage. White-light LEDs (the most common type of LED) are used to backlight displays in smartphones and tablet computers. Although the light emitted by these LEDs appears white, their emission spectra show peak emissions at wavelengths corresponding to the peak of the blue light. This has raised concerns that the cumulative exposure from such sources may damage the retina and potentially increase the risk of age-related macular degeneration.

Blue-blocking spectacle lenses, with varying degrees of short-wavelength light attenuation (ranging from 10% to 100%), are being marketed to the general population with claims that they can alleviate eyestrain and discomfort, improve sleep quality, and provide protection from retinal damage from computers and other devices. However, a review of current scientific literature did not identify any high quality clinical trial evidence to support these claims.

Here are some tips to limit exposure to blue light:

• Especially at night, lower the light intensity of screens from computers and other devices.
• Use dim red lights for night-lights. They are less likely to shift circadian rhythm and suppress melatonin.
• Avoid looking at bright screens two to three hours before bed.
• Expose yourself to lots of bright sunlight during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.

Be safe, be healthy, be six feet apart!