Daylight includes visible light and invisible light, and the light emitted by Taiyang may include a series of different colors of light. These rays contain different amounts of energy. Sunlight contains red, orange, yellow, green, cyan, blue, and purple light, and the spectrum of these lights combine to produce what we call “white light” or sunlight.
There is an inverse relationship between the wavelength of light and the energy it contains. Light with a relatively long wavelength contains less energy, and this energy is less. Light at the blue end of the spectrum has a shorter wavelength and more energy.
Electromagnetic rays beyond the red end of the visible spectrum are called infrared rays. They are warming, but no light is visible. At the other end of the visible spectrum, blue light with the shortest wavelength (and highest energy) is sometimes called blue-violet or violet light. This is why the invisible electromagnetic radiation that just exceeds the visible spectrum is called ultraviolet (UV). Ultraviolet rays have higher energy than visible light, which enables them to produce tanning changes on the skin.
Blue light is generally defined as visible light in the range of 380 to 500 nm. Blue light is sometimes further decomposed into blue-violet light (approximately 380 to 450 nm) and blue-green light (approximately 450 to 500 nm). Therefore, approximately one-third of all visible light is considered high-energy visible light (HEV) or “blue” light. Like ultraviolet radiation, visible blue light (the shortest wavelength and highest energy part of the light spectrum) has both benefits and dangers.
1. The source of blue light
Sunlight is the main source of blue light, and being outdoors during the day is where most of us are exposed to sunlight. However, there are many man-made indoor blue light sources, including fluorescent lamps, LED lighting and flat-screen TVs. The most notable is that the display screens of computers, electronic laptops, smart phones and other digital devices emit a lot of blue light.
The HEV light emitted by these devices is only a small part of the light emitted by the sun, but the time people spend using these devices and the proximity of these screens to the user’s face make many ophthalmologists and other healthcare professionals worry about the effects of blue light. Long-term effects on eye health.
2. Blue light makes the sky look blue
When short-wave high-energy rays on the blue end of the visible light spectrum hit air and water molecules in the atmosphere, they are more easily scattered than other visible lights. The high degree of scattering of these rays makes the cloudless sky look blue.
3. Blue light can reach the retina directly.
The anterior structure of the adult eye (cornea and lens) is very effective in preventing ultraviolet rays from reaching the photosensitive retina at the back of the eyeball. Even if you are not wearing sunglasses, less than one percent of the sun’s ultraviolet rays will reach the retina. But almost all visible blue light passes through the cornea and lens and reaches the retina.
4. Blue light may increase the risk of macular degeneration.
The fact that blue light penetrates all the way to the retina (the inner layer behind the eye) is important because laboratory studies have shown that excessive exposure to blue light can damage the photoreceptor cells in the retina, which can cause changes similar to macular degeneration , Resulting in permanent vision loss. Although more research is needed to determine how much natural and artificial blue light is “too much” for the retina, many eye care providers worry that the increased blue light exposure of computer screens, smartphones and other digital devices may increase by one. People are at risk of developing macular degeneration later in life.
Post time: Jul-28-2021