Night four, the first lights, red, orange, yellow, green, blue and purple, colorful LED lights dotted the night, but also attracted the attention of researchers. A recent study in Nature Aging and Disease Mechanisms found that blue light produced by light-emitting diodes may damage brain cells and the retina, and accelerate the aging process.
After the study was published, many suggestions for improving or reducing the adverse effects of blue light on the human body continued, such as wearing amber lenses and other methods to filter out the blue light emitted from the screens of electronic devices such as cell phones or tablets, and improving the screens of electronic devices to reduce the production of blue light.
From the 2014 Nobel Prize in Physics for the invention of a method of preparing blue light LEDs, to the exposure of papers on the "harmful" effects of blue light in recent years, from the perspective of life and health, people are curious to know whether blue light is as damaging to the human body as ultraviolet and infrared rays. Is there a need to deal with the damage caused by blue light to the human body?
Large amounts of blue light exposure is not common
As early as the 1970s, LEDs have been developed in red, orange, yellow and green, but blue LEDs have been plaguing the research community. The lack of blue LEDs has led to a long-term "three missing" of the three primary colors of red, yellow and blue, and artificial access to white light sources has been hindered.
Ge Aiming, an associate professor at Fudan University's Department of Lighting and Lighting Engineering, told China Science Bulletin that the reason why LEDs can emit different colors of light is because of the different materials in them. Gallium arsenide diodes emit red light, gallium phosphide diodes emit green light, silicon carbide diodes emit yellow light, and the preparation of materials that can emit blue light is difficult to achieve.
Until 1989, Japanese scholars akasaki yong and amano hao made gallium nitride, the world's first blue LED. since then, nakamura shuji created a large number of production of gallium nitride crystals of technology, and therefore won the 2014 Nobel Prize in physics. Gallium nitride diodes are officially on the international stage, used in medical, electronic displays, lighting and other fields.
Ge Aiming said that the artificial white light lamps made of red, green and blue light, blue light content accounts for a relatively high percentage, however, the intensity of blue light is not high. In addition, there are not many opportunities for humans to be exposed to high-intensity blue light in large quantities. Even for the treatment of neonatal jaundice blue light lamp, a long time in the process of clinical application, there has been no damage to the reported cases, it is too early to talk about "blue" color change.
Liu Qiang, a professor at the School of Life Sciences at the University of Science and Technology of China, said that the optic nerve is connected to the central nervous system, and long-term exposure to large amounts of blue light can damage the retina, thereby causing damage to the brain. Similar to the damage caused by lasers, ultraviolet and infrared rays, the effect of blue light on the human body is positively correlated with the amount of blue light exposure, and this effect may be a slow cumulative effect.
Lack of clinical evidence
Does blue light actually affect humans? And how does it affect humans?
Zhou Qiang, deputy director of the People's Hospital of Peking University, said that long-term exposure of the eyes to blue light can increase the amount of toxins in the macula within the eye, thus damaging the retina, and such cases are usually found in animal experiments. Moreover, this is not an isolated case, long-term, high-dose exposure to red light, green light and other light can lead to similar results. For example, he said, "snow blindness" occurs when large amounts of white light are reflected off snow and ice into the human eye, impairing normal eye function.
Another study found that blue light stimulates a particular type of nerve cell in the retina, which is associated with the area of the brain that controls wakefulness. When stimulated by blue light, these cells inhibit melatonin secretion, and a decrease in melatonin levels or affect sleep.
Ge Aiming said light is significant to the growth of plants and animals, and blue light is part of natural light, and its significance to humans should not be underestimated.
To address the issue of blue light causing aging, Liu Qiang explained that the research community has confirmed that the factors that can lead to human aging mainly include environmental factors and genes. Environmental factors, some chemical inducers can lead to aging; gene level, Japan, Europe, some family lines, Lamin A/C gene mutation can lead to premature aging.
And the collection of effects of blue light on the human body has yet to be verified.
Experimental results difficult to verify in humans
A Spanish study showed that more exposure to blue light at night may increase the risk of breast and prostate cancer.
A British study showed that exposure to blue light significantly lowers systolic blood pressure, increases heart rate and reduces the risk of cardiovascular disease. Japanese experts found that irradiating damaged spinal cord nerve cells in rats with blue light resulted in an increase in proteins that promote cell growth, which in turn accelerated the recovery of the damaged parts.
In fact, it is difficult to verify the effects of blue light on humans. Liu Qiang said the study, in which only fruit flies were experimented with, does not scientifically prove the effects of blue light on humans. Unlike research on slowing down aging, research on promoting aging is difficult to verify in humans.
"The effects of blue light on the human body need to be tracked over time, and with blue light as a new thing, the question will be answered in decades or centuries. Even if blue light's damage to humans is certain, exploring how large a dose will trigger the damage is a difficult study." Liu Qiang said.
Clinical cases are also quite difficult to obtain, Zhou Qiang told China Science Daily. Clinically, there have been no large-scale cases of people seeking medical attention because of blue-light damage, and there is no evidence to directly prove that humans are affected by blue light.
"Currently, the industry is strengthening the research and development and use of full-spectrum lamps to replace white light lamps made of blue-light-excited phosphors, creating a natural and healthy high-quality light source." Ge Aiming said.
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