Something About Blue Light
What’s blue light?
Sunlight contains blue, green, yellow, orange, red light rays and so on. Wavelength 380nm to 700nm is normally called visible light by the scientists. Blue light is generally defined as visible light ranging 380nm-500nm (approximately about 1/3 of the visible light), which gets the shortest wavelength but highest energy in the visible light spectrum.
Where does it come from?
Blue light comes from sunlight, and some other man-made sources like LED lighting and flat screen TVs, display screens of computers, etc.
Sun light is the main source, and the main exposure to it is when we going outdoors during daylight.
Digital devices like smart phones and computers emit an amount of blue light. Compared to sunlight, the amount emitted by digital devices is very small. But considering the time people spend on the computers, electronic notebooks, smart phones and other digital devices, this small amount counts.
What Effects does it have?
Every coin has two sides. Blue light is not an exception. The positive effects as below:
It is very important for body’s natural circadian rhythm (regulating the wakefulness and sleep cycle). Exposure to blue light in daytime helps maintain a healthy circadian rhythm, while too much exposure in nights can cause sleepless in nights and fatigue in daytime.
Researches show that high-energy visible light boosts alertness, helps memory and cognitive function and elevates mood. In fact, blue light is used in light therapy to treat seasonal affected disorder (SAD). Appropriate exposure to it can do good for health.
The negative effects are:
Risk of aging related macular degeneration.
The lens of the adult human eye blocks nearly 100% of the ultraviolet rays from sun. But with the aging process going on, the eye natural lens’s protection function degrades. According to scientific studies, blue light can pass through the cornea and lens to the retina, too much exposure to it can damage the light-sensitive cells in the retina, and thus it may increase the risk of aging related macular degeneration.
Cause computer vision syndrome.
The short-wavelength, high energy blue light is more easily unfocused. When people look at the computer display screen, smart phones, electirc notebook and other digital devices, these devices will emit a significant amount of blue light, and the unfocused light will reduce the contrasts and cause computer vision syndrome: digital eye strain, eye fatigue, dryness, blurred vision, etc.
After all, we don’t have to worry too much as we already have some solution for the eye protection with special lenses.