In recent years, as the production and marketing of energy saving products as well as enhancement of our energy saving awareness, incandescent gradually fade out of our lives, which is replaced by a new type of fluorescent lamps and light emitting diodes(LED. But it also brings trouble to our lives,the energy situation is certainly gratifying, but the proportion of blue light in new light sources is high over incandescent, many of us have reported that the eye tend to be tired and other health problems when being illuminated by the LED,the longer increasingly we use computers, mobile TV, the worse we feel.
Is light issued by LED lamp really harmful to the eyes?
This is a question worthwhile exploring and giving the exact answer for us. The daylight We have contacted the natural light, the human eye is also a product evolved by biological, which has adapted to the sun as the light-emitting body. Different wavelengths of visible light cause us different color vision, the colors of which are arranged sequentially from long to short according to the wavelength of light we feel are: red, orange, yellow, green, cyan, blue, purple. Blue and purple is the visible light with short wave. When these light with different wavelengths simultaneously into our eyes, we feel that they are the white light. A Newton's famous experiment is to allow the white light to be broken down into seven color spectrum when a bunch of sunlight through the prism,. It is most sensitive to yellow-green light, which is the longest wavelength of the Earth's surface. From the yellow-green light to the blue and violet light with short wavelength, the intensity is also waning. There is a certain amount of ultraviolet and infrared in the solar spectrum, but the human eye is not sensitive to ultraviolet and infrared. Infrared radiation on our skin can cause hot feeling, it is also known as thermal radiation. Too strong or too long UV irradiation will burn the skin, which can also damage the eyes.
We know that the spectrum of an incandescent lamp approximates sunlight, the light emitted is also slightly orange, which is the light color we are more willing to accept during the history of human evolution. The light-emitting principle of LED is different from the incandescent,there are more blue light issued in the spectrum, those at a wavelength near 450 nm are strong blue light, although this is the most affordable lighting source in view of the economic, but have a greater difference with the solar spectrum the human eye are accustomed to, over time, the LED light will adversely harm to the health of human eye particularly for the colorful light.
Then what kind of injuries on our eyes for the blue light emitted by the LED lights?
According to statistics, the blue light emitted by LED light during the day can improve people's attention, and mood. At night, by contrast, prolonged exposure to blue light will send the signals to the brain to reduce the secretion of melatonin, and this substance can regulate people's biological rhythms, once missing,our circadian rhythm will be disrupted, causing insomnia and other symptoms, prolonged exposure to blue LED will also affect our mental health.
When entering the eye, the light is absorbed by the cell within visual molecules, causing a photochemical reaction, resulting in vision,that’s why the visual cells is damaged, particularly for blue light with short wavelength. It was found that the photon energy of shortwave light in the visible spectrum is more than the energy of longwave photons, which is easily absorbed by certain biological macromolecules. After absorbing the photons,the molecules will at a high-energy excited state; biological macromolecules excited will interact with other molecular and produce reactive oxygen species and free radicals in the retina, causing photochemical damage in the retina, resulting in degradation of cell function and apoptosis . Most of these damages are not recoverable. Eye cornea, lens and vitreous will absorb a certain amount of blue light, which can protect the retina against less susceptible to blue. However, absorbing the blue light, the lens will accelerate the turbid, which will accelerate the formation of senile cataract.
How to protect us from being hurted by LED light?
First of all, we should avoid prolonged work in bright light in order to protect the eyes, shortening the time in the face of a variety of screen. Proper use of protective eyewear is also a way to protect the eyes. For example, using sunglasses in strong sunlight and a slight yellow wearing goggles glasses absorbing blue light when watching the screen for a long time.
Secondly, in general, the proportion of blue light emitted by LED with warm colors is less than those with cool colors, the brightness of LED lamp with a diffuser is lower than that of those without cover or with a transparent cover. When we buy LED lighting products, we shall pay attention to the product colors and surface brightness.
Finally, it is difficult to completely avoid infringement of the blue for the workers in face of the computer every day, there is need to add a layer of anti-PC blue protective film to reduce the blue light so that shortwave blue light energy can be absorbed and converted into to achieve the protection of the eyes.
Every coin has two sides, so do the LED light. Like other light sources, LED light radiation theoretically cause harm to humans. But it actually significantly attributes to the energy conservation to our community, after all, LED light just started developing for 60 years!
