Mobile phone screen "blue light" is the main reason for the surge in myopia rates

Mobile phone screen "blue light" is the main cause of the surge in myopia rates, causing more than 30,000 blind people each year

——Analyzing the principle of electronic screen "blue light" comprehensively attacking the vision defense line from a scientific perspective

Author: Yu Wulong (Chinese popular science writer)

On May 22, 2022, the Aier Eye Hospital of Central South University and other institutions released the "2022 China-Europe International Myopia Surgery White Paper" big data report, which showed that the number of myopia surgeries in China and Europe has doubled in four years. At present, there are about 2.5 billion myopic people in the world, and the number of myopic people in China is as high as 600 million. It is predicted that by 2050, the number of myopic people in the world will reach 4.949 billion. The data also shows that the incidence of myopia in Asia is higher than that in Europe and the United States, and the incidence of myopia in China is 48.5%, ranking first in Asia.

According to data from the World Health Organization (WHO) Eye Care Association, more than 30,000 people worldwide go blind every year due to "blue light" and "radiation". According to data from the Ophthalmology Branch of the Chinese Medical Association, among the 420 million Internet users in China, 63.5% of them have varying degrees of eye diseases such as decreased vision, cataracts, and blindness due to "blue light radiation".

With the rapid development of science and technology, smart electronic products such as mobile phones, computers, PADs, and VR have become popular, and the public has entered the "screen reading" era. The emergence of electronic products has completely changed the public's lifestyle and eye usage patterns. Long-term use of mobile phones and computers is no longer just a daily routine for office workers, but also a normal part of students' lives. People almost live in a "blue light" siege composed of mobile phones, computers, PADs, VR and other electronic products. The eyes may be harmed at any time, resulting in frequent "electronic screen visual syndrome". In order to further spread the popular science knowledge of vision protection, this article will analyze the principle of electronic screen "blue light" from a scientific perspective to comprehensively capture the vision defense line.

1. Be sure to recognize the vision killer "blue light" that can cause blindness

"Blue light" is the light closest to ultraviolet light waves and has the highest energy. Its wavelength is between 400 and 500 nm (nanometers). It appears blue to the human eye. This article analyzes the "blue light in the spectrum of artificial light (i.e. light emitted by electronic screens such as mobile phones)" in the figure below.

(“Blue light” is the “white” in the picture. According to the color composition principle of “chromaticity”, “red, green, and blue” three primary colors are added in equal amounts to form “white”)

"Blue light" is more harmful to the human body than other wavelengths of light. Short-wave "blue light" has extremely high energy, also known as "high-energy blue light", which can penetrate the lens of the eye and reach the retina directly, causing light damage to the retina, directly or indirectly causing damage to the macular cells. "Blue light" will increase the amount of toxins in the macular area of ​​the eye, seriously threatening our fundus health. Long-term exposure to "blue light" can cause severe vision damage and macular degeneration, and symptoms such as red eyes, dry eyes, astringent eyes, blurred vision, visual fatigue, headaches, back pain, shoulder pain, and cervical pain will appear. Studies have shown that "blue light" is not only present in sunlight, but also exists in large quantities in electronic products such as computer monitors, fluorescent lamps, mobile phones, digital products, LED screens, bathroom heaters, projectors, laser pens, and flashlights.

2. Analysis of the hazards of blue light and its mechanism of eye damage

Studies have found that blue light is closely related to retinal light damage, and studies have shown that apoptosis may be an important mechanism for "blue light" to mediate retinal damage. Blue light stimulation changes the activity of some enzymes in the retina, affects the normal metabolic process of the retina, and causes retinal damage. Blue light inhibits the activity of cytochrome oxidase. Blue light is so harmful, but many people are completely unaware of it.

The absorption peak of rhodopsin causes the most serious damage to the retina. Experiments have shown that the retinal light damage spectrum is consistent with the absorption spectrum of rhodopsin, and the absorption peak of rhodopsin causes the most serious damage to the retina. Short-wave light such as blue light causes more serious damage to the retina, and its action spectrum does not match the characteristics of the rhodopsin absorption peak. Blue light has a photoreversal effect on bleached rhodopsin, causing obvious damage to the retina, suggesting that the amount of rhodopsin plays an important role in retinal light damage. Although the action spectrum of blue light is inconsistent with the absorption peak of rhodopsin, blue light has a photoreversal effect on bleached rhodopsin, which can quickly resynthesize bleached rhodopsin into rhodopsin. In this way, when irradiated with blue light, the retina can generate a large amount of active rhodopsin, which significantly improves the photosensitivity of the retina, so the retina is more sensitive to blue light.

Apoptosis and blue light damage. Apoptosis refers to the process of cell death caused by factors inside or outside the body triggering the pre-existing death program in the cell. Studies have shown that apoptosis may be an important mechanism for blue light-induced retinal damage.

Free radicals and lipid peroxidation. Lipofuscin is the residue of retinal pigment epithelial cells engulfing and digesting the outer segments of rods and cones. With age, its deposition in the secondary lysosomes of the retinal pigment epithelium increases. Recently, it has been found that A2E is the main component of lipofuscin. It is a non-degradable pigment that can spontaneously fluoresce and has the characteristic of strongly absorbing blue light, which increases the sensitivity of the retinal pigment epithelium to blue light. It is now believed that A2E is an important cause of macular degeneration. Under aerobic conditions, blue light stimulates the retina to initiate the photooxidation mechanism, inducing the production of singlet oxygen, hydrogen peroxide, and hydroxyl free radicals, forming a severe oxidative stress state, destroying the body's normal redox dynamic balance, causing damage to biological macromolecules, and leading to apoptosis of photoreceptor cells and pigment epithelial cells. Studies have shown that mitochondria are the main site for the production of free radicals. Mitochondria contain flavin oxidase and cytochrome C oxidase, which are important respiratory enzymes of mitochondria and have the characteristics of absorbing ultraviolet and blue light bands. The absorption peak is at 440m. Under aerobic conditions, photooxidation reactions occur, producing free radicals, destroying mtRNA and proteins, increasing the permeability of mitochondrial membranes, reducing transmembrane potential, and inducing cell apoptosis. In addition, A2E oxide can specifically act on cytochrome C oxidase, causing changes in mitochondrial function and initiating cell apoptosis. Oxygen free radicals can destroy the stability of lysosomal membranes, and the contents of lysosomes enter the cytoplasm, causing cell degeneration and apoptosis. The outer segment of photoreceptor cells is the tissue with the highest amount of long-chain unsaturated fatty acids in the body. Singlet oxygen and hydrogen peroxide cause lipid peroxidation. Although superoxide anions are inactive, their protonated form, peroxyhydroxyl free radicals, can attack diallyl hydrogen atoms in unsaturated fatty acids. In addition, the oxidation product of unsaturated fatty acids on the cell membrane, peroxyhydroxyl 24-carbon tetraenoic acid, has a strong effect of inducing cell apoptosis. Researchers believe that photoreceptor cell apoptosis is mediated by rhodopsin. Studies have also found that cfos is a proto-oncogene that can induce neuronal apoptosis. Its encoded product, cfos protein, is a member of the transcription factor activated protein 1 (AP-1) complex. Recent studies have shown that cfos plays an essential role in blue light-mediated photoreceptor cell apoptosis. Blue light's damaging stimulation of the retina is converted into intracellular death signals, which are transmitted to the effector and activate AP-1, accelerating the expression of apoptosis-related genes and inducing cell apoptosis.

Enzyme activity and blue light damage. Blue light stimulation changes the activity of some enzymes in the retina, affecting the normal metabolic process of the retina and causing retinal damage. Blue light inhibits the activity of cytochrome oxidase 2129. When the illuminance of blue light on the retina reaches 110kJ/㎡, it has an inhibitory effect on the activity of cytochrome oxidase. This effect is reversible. When the illuminance reaches 380kJ/m2, it produces an irreversible inhibitory effect on cytochrome oxidase, affecting the function of mitochondria in cells and initiating cell apoptosis. Blue light stimulation reduces the activity of sodium-potassium ATPase, redistributes sodium, potassium, and chloride inside and outside cells, increases sodium in cells, causes an increase in intracellular osmotic pressure, and extracellular water enters cells, causing cell edema, swelling of mitochondria and endoplasmic reticulum in cells, and loosening of cytoplasm, leading to progressive degeneration of photoreceptors. Blue light stimulation can activate the activity of prostaglandin synthase G/H. Hanna NDS reported that blue light stimulation of pig eyes caused a decrease in the amplitude of a and b waves of the pig electroretinogram and an increase in the levels of retinal prostaglandins and peroxides. It is considered that blue light stimulation activates prostaglandin synthase G/H, increasing the synthesis of prostaglandins. The latter can also act as a pigment group, absorbing blue light, causing photooxidation reaction, producing a large number of oxygen free radicals, causing retinal damage, and initiating apoptosis.

Threshold and distribution of blue light damage. The intensity of blue light is distributed differently in different parts of the retina. The Monte-Carlo method was used to estimate the distribution of blue light in different parts of the retina. The results showed that the retina 4mm above the macula was exposed to the most blue light and ultraviolet light, and the peripheral retinal illumination gradually decreased at a certain ratio. Retinal light damage is related to many factors, such as: wavelength and intensity of the action spectrum, direction, time and distance of light source, pupil size, age, lens condition, etc.

Real-life experiment. In 2017, Dalian Medical University also tried a real-life experiment. While ensuring human safety, the damage was controlled within the range that the human eye can recover. The subjects were 30 teachers and students aged between 18 and 40. Considering that human eye damage is irreversible, the subjects were only allowed to use the iPad for one hour. The macular pigment density in the macular area of ​​the human eye was tested before and after using the iPad. It was found that after the 30 subjects used the iPad for one hour, the blue light emitted by the screen would cause the macular pigment density to decrease. Macular pigment has a certain protective effect on retinal light damage. Its density may affect the structure and function of retinal cells, causing protein denaturation and apoptosis of photoreceptor cells. Once degeneration and apoptosis occur, it will seriously affect vision loss and cause irreversible damage to vision.

3. “Blue light” hurts the eyes, but we cannot perceive the damage

Through the above analysis, we know that "blue light" hurts the eyes. There is "blue light" in sunlight, and there is "high-energy blue light" in the light emitted by various screens such as mobile phones and computers. Although the intensity of blue light in sunlight is stronger than that of mobile phones, sunlight is not necessarily more harmful to the eyes, because in general, as long as we do not look directly at the strong sunlight, the sunlight will not directly enter the eyes.

We have such a feeling that it is difficult to see the mobile phone screen clearly under strong sunlight, because the sunlight is stronger than the light from the mobile phone screen. When we are in an environment away from sunlight, such as the shade of trees, we can see the mobile phone screen clearly, because at this time the sunlight is weaker than the light from the mobile phone screen after reflection and absorption. In modern life, we spend most of our time indoors, and the light environment indoors is similar to that under the shade of trees. At this time, looking directly at the mobile phone, the light from the mobile phone screen is stronger than the reflected sunlight. Moreover, after millions of years of evolution, human eyes have become accustomed to seeing things with the help of reflected light. Since the human eye is not evolved to look directly at the light source, when we move from outdoors to indoors, the light entering the eye becomes artificial light and the light from the 3C electronic screen, so the "high-energy blue light" of the electronic screen, that is, white light, enters the eye in a direct manner.

Since human eyes are not designed to look directly at light sources but to use light to assist in seeing things. The white light from mobile phones and computers enters the human eye in a direct manner. When facing such electronic screens, the average distance between the human eye and the electronic screen is only about 20cm. According to the first law of illumination (E=cL/r2), the energy of light is inversely proportional to the square of the distance from the eye to the electronic screen. The mobile phones, computers, pads, VR, etc. that we come into contact with on a daily basis are very close to the human eye, especially VR. Under the same brightness, the energy entering the eye is 10,000 times different from that of TV. When facing the electronic screen at a close distance, the "high-energy blue light" emitted by the electronic screen is very strong, and it enters the human eye in a direct manner, destroying the habit of the eyes to see things with the assistance of sunlight. There is no doubt that the "high-energy blue light" in the electronic screen will be more destructive and lethal to the human eye than the reflected blue light from the sun!

Comparing the above figure, we can see that the light emitted by electronic screens such as mobile phones is completely different from sunlight. The sunlight spectrum shows that sunlight is "low blue and high green", and the energy of blue light is estimated to be 0.9 times that of green light. The spectrum of artificial light LED is "high blue and low green", and the energy of blue light is estimated to be 4.5 times that of green light. The damage of blue light to the eyes actually depends on two factors, one is the intensity of light, and the other is the length of time. If you are exposed to white light LED for a long time, the "high-energy blue light" can easily damage your glasses.

"Blue light" is harmful to the eyes, but when measuring the spectrum of electronic screens with a spectrum analyzer, the blue ratio will be low. As shown in the figure below, it is only about 2.8%. The blue ratio of only 2.8% is obviously inconsistent with the high blue light peak in the spectrum. The total amount of blue light generated by the electronic screen cannot be only 2.8%. The blue ratio is actually the numerical ratio obtained by multiplying the blue light intensity in the electronic screen spectrum by the bright vision curve. It reflects the degree of our human eye's perception of blue light, not the blue light energy ratio of the electronic screen.

The photopic vision curve is an experiment conducted by the International Commission on Illumination (CIE) on hundreds of people in 1924. The curve is based on the sensitivity of the human eye to light after shining light of different wavelengths and the same brightness on the human eye. Because the number of cone cells that perceive color in the human eye is unevenly distributed, the human eye has different perception abilities for light of different wavelengths. The blue ratio is low, which means that in the process of "blue light" harming the human eye, we do not know that the harm is happening, which is very dangerous.

"Blue light" is dangerous, but we cannot sense the damage. Human retinal damage is irreversible. The second part of this article is a scientific experiment on blue light eye damage. In fact, the progress of science cannot always stay on the study of blue light eye damage. Therefore, in recent years, the most important topic is to study how to protect and repair human retinal light damage. Holographic bio-microwave technology has a good effect in this regard.

In summary, the eyes are not sensitive to "blue light", and the "high-energy blue light" from electronic screens enters the eyes directly at close range, destroying our habit of seeing things with reflected light, causing the eyes to be injured unknowingly. There is no doubt that blue light hurts the eyes. When the "high-energy blue light" emitted by electronic screens such as mobile phones is further reflected on the lenses of myopia glasses, it forms a combination of electronic screens and myopia glasses to attack the fragile visual defense line of human beings (please pay attention to the "Basic Principle Analysis of Myopia Glasses More Myopia" published on the "Popular Science China" cloud platform). Therefore, this is the main reason for the continuous surge in myopia rates in recent years. However, what is even more fatal is that due to the lack of correct understanding in this regard, people do not know that "high-energy blue light" damage is happening. Only by continuously improving the public's awareness of "anti-blue light" and preventing blue light before it happens can eye health be guaranteed. This will be the direction that humans will work towards next.

4. Effective methods to prevent "blue light" from damaging your eyes

First of all, I strongly recommend "holographic biological microwave glasses". Scientists have found that biological information energy can improve the ion permeability of living bodies. It is also an electromagnetic trigger signal that can play a lever role, correct abnormal changes in cells, change the imbalance of molecules, activate cells, restore the correct communication and coordination between cells, and even activate potential genes in living bodies, replace aging and pathological genes, and achieve the reversal of aging. Medical experiments have shown that the young and vigorous biological information energy emitted by plants is the main energy source for curing changes in the information spectrum of the human body and solving "information hunger". It is a special substance. If material nutrition in the usual sense is mainly molecular nutrition, then information nutrition is quantum nutrition, which is a magical power that can change the motion state of atoms, electrons and other microscopic particles.

The frame of the holographic biological microwave glasses is a plastic titanium frame. The titanium frame is equipped with crystal powder of biological materials. The crystal powder of biological materials makes the frame produce biological microwaves that are beneficial to the eyes. The biological microwaves resonate with the frequency of the eyes and act on the eye cells, thereby promoting the microcirculation of the eye tissue, relieving eye fatigue and improving the condition of the eyes, so that the eyes can improve vision in a relatively short time, eye diseases can be effectively conditioned, and they will continue to be effective without rebound. It is recommended that everyone can wear holographic biological microwave glasses for a long time regardless of whether they have eye diseases or not, because the glasses can not only play a role in regulating eye diseases, but also play a good role in protecting the eyes. Nowadays, most people watch electronic screens such as mobile phones, computers and TVs for a long time, which is an unhealthy eye habit. Wearing holographic biological microwave glasses can greatly relieve eye fatigue. In addition, the elderly and people with unstable center of gravity can wear holographic biological microwave glasses to stabilize the center of gravity. For specific content, please pay attention to the "Scientific Principles of Holographic Biological Microwave Glasses to Protect and Restore Eye Health" published on the "Popular Science China" cloud platform.

Secondly, anti-blue light glasses are functional glasses that can filter or absorb harmful light such as blue light to protect the eyes. Ordinary anti-radiation lenses can only filter ultraviolet rays and certain electromagnetic radiation, but cannot filter blue light. Anti-blue light goggles can not only effectively isolate ultraviolet rays and radiation, but also filter more than 40% of blue light. They are suitable for use when watching computers or TV, greatly reducing the stimulation of blue light to the eyes, eliminating discomfort symptoms such as sore eyes, fever or pain, and relieving eye fatigue.

Professional digital protective glasses are not just blue light protection goggles, but professional protective glasses that integrate blue light protection, radiation protection, and UV protection. At present, the blue light protection goggles market is mixed with many types, ranging from a few yuan to thousands of yuan. Those with too low prices are often inferior products. Not only will they not work, but they will also cause greater damage to the eyes. The following will teach you how to choose a good pair of blue light protection goggles. 1. Comply with national standards for lenses. This is the basic principle for selecting lenses. The various indicators of the lenses should fully comply with national standards. Due to blue light protection. The lens manufacturing process is complex. If there is a slight mistake, the parameters of the lens itself will deviate from the national standards and cause greater damage to the eyes. 2. Blue light blocking rate of 35%~50%, absorption design. Blue light protection lenses also have strict requirements for blue light blocking rate. If the blocking rate is too low, the effect is not obvious and the eyes are still damaged. If the blocking rate is too high, the lens will filter out harmless blue light, causing color distortion when the human eye sees objects, and it will also cause an increase in the proportion of red light, which will damage the eyes. The surface of the absorption design is a special light brown, the actual contrast is improved, the blue light blocking effect is better and more stable, and it is clear at a glance with props demonstration. The anti-type design reflects through the surface of the lens, making the lens reflect too much, reducing the transmittance of the lens, and also causing secondary damage to the blue light. The effect of the blue light demonstration props is also an important criterion and basis for consumers to judge the anti-blue light lenses. 3. Inspection by the authoritative part. Anti-blue light goggles are not ordinary glasses, but functional glasses. Good anti-blue light glasses can protect the eyes. Glasses without quality assurance may be counterproductive after wearing. Therefore, it is best to have a national authority to conduct a systematic evaluation of the safety and effectiveness of glasses, such as a medical device registration certificate.

Note: Some of the scientific research data, professional technical introduction and pictures in this article are derived from professional materials, papers and the Internet.

About the author: Secretary-General of the Vocational Education Committee of the Education Chamber of Commerce of the All-China Federation of Industry and Commerce, member of the China Science Writers Association, leader of the "14th Five-Year Plan" research group on educational informatization of the China Educational Technology Association, and senior member of the China Wildlife Conservation Association.