The incidence of myopia in Chinese students in 2005 was 27% in primary schools, 53% in junior high school students, 73% in high school students, and 78% in college students. The low vision rate of high school graduates in coastal cities has reached 85%. The incidence of myopia in Chinese 15-year-old students is as high as 81%. More serious is the increased incidence of high myopia that can cause blindness. In 2005, the rate of detection of poor eyesight among students in Beijing continued to rise, with 31% of primary school students, 62% of junior high school students, and 78% of high school students, which was higher than the national average. The detection rate of students with poor eyesight in Shanghai is the highest in the country, 42% of primary school students, 74% of junior high school students, and 81% of high school students, which is higher than the national average. The myopia rate of Chinese students has ranked second in the world. The number of adolescents blinded by myopia in China has reached 300,000. The vast majority of students' vision loss is caused by excessive eye use.
In the case of such a high proportion of myopia patients, as people continue to deepen their understanding of the importance of vision protection, many lighting manufacturers meet the needs of the market, have launched the so-called "new technology, new products" lighting table lamp - "Eye-protecting table lamp". Because the relationship between "eye protection" and the performance of table lamps has not undergone rigorous scientific argumentation, and "eye protection" lacks relevant medical clinical evidence, there is no scientific basis for the term "eye protection table lamp" on the market.
The characteristics of the so-called "eye protection table lamp" in the market
The so-called "eye protection table lamp" on the market, the selling point is that it claims "no stroboscopic, eye protection function". Most "eye protection" desk lamps use electronic ballasts to operate fluorescent lamps at high frequency currents. The frequency is usually above 20 kHz, which is 50 Hz compared to the use of an inductive ballast to operate a fluorescent lamp at a commercial frequency current. In other words, the human eye barely feels high-frequency flicker. However, even if the human eye does not feel it, the strobe still exists, but the stroboscopic light when the fluorescent lamp is operated with the high frequency electronic ballast is smaller and faster than the strobe when the power frequency magnetic ballast is operated. However, the high-frequency flicker affects the work of visual research. It is not certain that the response of the retinal nerve caused by high-frequency light stimulation will affect the visual function of any sensory or motor nerve, so it is difficult to determine whether it can effectively protect the eye.
At present, many merchants use the gyro test method to prove to consumers the so-called eye protection effect of "eye protection table lamp". The gyro test method is a simple method to illustrate the stroboscopic effect. It only shows that the stroboscopic light when the fluorescent lamp is operated with the high frequency electronic ballast is smaller than the stroboscopic operation when using the power frequency magnetic ballast. It cannot be proved. The effect of eye protection.
The comfortable lighting provided by the desk lamp can be scientifically evaluated
The comfort of table lamp illumination is evaluated by the illuminance on the visual work, the ratio of the maximum illuminance/minimum illuminance on the visual work, the illuminance around the work, and the ratio of the work/surround/environmental brightness. The lighting requirements for general reading and writing operations are 200 to 500 lux (lx) for short periods of time and 500 to 1000 lux (lx) for long periods of time; the ratio of maximum illuminance/minimum illuminance for visual operations is less than or equal to 3; The ambient illuminance is 1/2 visual work illuminance value and greater than or equal to 200 lux (lx); the ratio of work/surround/environmental brightness is 10/3/1 for short time and long time; the illumination requirement for computer work is keyboard 300, File 500, screen 200 lux (lx).
Provide relevant standards for comfortable lighting lamps
1.GB7000.11—1999 “Safety Requirements for Portable General Luminairesâ€
2.GB7000.1-2002 "General Safety Requirements and Tests for Luminaires"
3. GBl7743—1999 “Limitations and Measurement Methods for Radio Disturbance Characteristics of Electrical Lighting and Similar Equipmentâ€
4.GBl7625.1—2003 “Electromagnetic compatibility limit harmonic current emission limit (device input current per phase ≤16A)â€
Lamps that provide comfortable lighting should meet the following requirements in addition to the safety and electromagnetic compatibility standards covered by the above 3C certification:
GB//T19473-200X "Reading and writing work table lamp performance requirements"; GB50034-2004 "Architectural Lighting Design Standards"; ISO8995:2002/CIES008/E-2001 "Indoor Workplace Lighting" should pay attention to the purchase of comfortable lighting table lamps:
1. Pay attention to the lampshade of the desk lamp, there should be a considerable amount of uplighting light, and the upper beam of light illuminates the surrounding environment. If only the light that is illuminating downward is too concentrated, the illuminance is high in a limited area, but if the range is not large, visual fatigue will occur after a period of use.
2. The height should be greater than or equal to 40 cm, preferably adjustable. If the height of the luminaire is below 40 cm, it is flush with the human eye or slightly lower, it is easy to produce a large contrast between light and dark, so that the eye is constantly adjusted to adapt to the change of light and dark; at the same time, the structure of the luminaire should properly block the side Strong light, when the eyes are at a height of 40 cm toward the lamp, you should not see the inner wall of the reflector and the light source, otherwise it will cause glare. These are all likely to cause visual fatigue, and long-term use can affect vision.
3. When purchasing the desk lamp for computer operation, pay attention to the height of the desk lamp, which is higher than the computer. Otherwise, the surrounding environment will become darker, so that the eyes will constantly adapt to the changes of light and dark, which is prone to visual fatigue.
The formation of myopia has a great relationship with the improper use of the eye. Excessive use of the eye is an important reason for the formation of myopia. At the same time, the formation of myopia has a certain relationship with genetics and nutrition. No matter what kind of luminaire is used, it will not prevent the fatigue caused by long-term use of the eye. There is no scientific basis for betting the child's eyesight to the "eye protection table lamp". The key to preventing myopia is to develop the habit of using scientific eyes. Pay attention to your own eye hygiene. When reading, be sure to sit correctly. It is best to rest every 45 minutes. Once, avoid eye fatigue; at the same time pay attention to the use of local lighting and overall lighting to form a comfortable lighting environment, so as to help protect the eyes.
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