What is Blue Light?
Sunlight is made up of red, orange, yellow, green, blue, indigo and violet light. When combined, it becomes the white light we see. Each of these has a different energy and wavelength. Rays on the red end have longer wavelengths and less energy. On the other end, blue rays have shorter wavelengths and more energy. Light that looks white can have a large blue component, which can expose the eye to a higher amount of wavelength from the blue end of the spectrum.
Where Are You Exposed to Blue Light?
The largest source of blue light is sunlight. In addition, there are many other sources:
· Fluorescent light
· CFL (compact fluorescent light) bulbs
· LED light
· Flat screen LED televisions
· Computer monitors, smart phones, and tablet screens
Blue light exposure you receive from screens is small compared to the amount of exposure from the sun. And yet, there is concern over the long-term effects of screen exposure because of the close proximity of the screens and the length of time spent looking at them. According to a recent NEI-funded study, children’s eyes absorb more blue light than adults from digital device screens.
What Are The Benefits of Blue Light?
Blue light is needed for good health:
· It boosts alertness, helps memory and cognitive function and elevates mood.
· It regulates circadian rhythm – the body's natural wake and sleep cycle. Exposure to blue light during daytime hours helps maintain a healthful circadian rhythm. Too much exposure to blue light late at night (through smart phones, tablets, and computers) can disturb the wake and sleep cycle, leading to problems sleeping and daytime tiredness.
· Not enough exposure to sunlight in children could affect the growth and development of the eyes and vision. Early studies show a deficiency in blue light exposure could contribute to the recent increase in myopia/nearsightedness.