“Doctor, is eye protection lamp useful or not, which brand is better to buy?” I believe that many parents have asked their doctors such questions in the course of ophthalmology clinics. On the usefulness of eye protection lamps, there are two extreme views, some manufacturers will over-exaggerate the efficacy of eye protection lamps, publicity, as long as the use of so-and-so brand of eye protection lamps, can play a very good myopia prevention and control, and some businessmen will even be myopia prevention and control of eye protection lamps and OK lenses (corneal reshaping lenses), frames of glasses on a par with the effects of eye protection lamps. On the other hand, some ophthalmologists put eye protection lamps down to nothing, saying that “all eye protection lamps on the market are IQ tax, useless. If you have the time and energy to pick eye protection lamps for your children, you might as well take them outdoors.” In fact, we need to look at the different claims about eye protection lamps in a dialectical way.
Is it necessary to buy eye protection lamp is currently known to be the most effective myopia prevention and control of light is sunlight, outdoor light can promote the release of intracranial dopamine, and dopamine can effectively inhibit myopia, to achieve the purpose of preventing myopia. It can be said that the sun is currently the only proven effective myopia prevention and control of “eye protection light”. Since sunlight is composed of ultraviolet light (UVR, wavelength below 400nm), visible light (VIS, wavelength 380-760nm) and infrared light (IR, wavelength above 760nm), there is no man-made lamp on the market that can simulate the effect of sunlight alone.
However, with the progress of the times, human habits have long been different from the ancestors of the “sunrise and sunset”, most of the children in the sun after sunset or reading, writing and other close eye activities. At this time, in the absence of sunlight, the choice and use of artificial light is particularly important. Therefore, in the absence of sufficient sunlight, the right choice of an eye lamp can indeed slow down the effects of prolonged close eye use on the progression of myopia. Therefore, eye protection lamps are still needed.
How to choose eye protection lamps eye protection lamps are advertised with a lot of jargon, resulting in many parents at a loss when choosing. You can refer to the following indicators:
● Light level A large number of clinical experimental studies have proved that the brighter the surrounding environment, the slower the growth of the eye axis will be. Professor Yang Zhikuan of the Optometry Group of the Chinese Medical Association reminds, “When a child is reading and studying at home, the value of the incoming light illumination should be no less than 125 lux (unit of illumination, hereinafter referred to as lux), which is an important factor that cannot be ignored when preventing myopia in children.” And according to the Ministry of Health and the Standardization Management Committee jointly issued the “People’s Republic of China primary and secondary school classroom lighting and lighting health standards”, the classroom desk surface illumination is not less than 300lux, classroom chalkboard illumination is not less than 500lux. international lighting specification CIES008/E-2001 in the office environment, the school environment, the library reading environment of the illuminance requirements are 500lux The international lighting specification CIES008/E-2001 for office environment, school environment, library reading environment is 500lux.
In addition, illuminance uniformity is also one of the criteria for judging the quality of eye protection lamps. Uniformity of illumination refers to the ratio of the minimum illumination on the specified surface to the average illumination. Illumination uniformity is closer to 1, that is, the more uniform distribution of light, the use of eyes will be more comfortable.
A lot of eye lamps in the introduction of the marked illumination is measured from the edge of the light source, and the actual eye illumination and light uniformity in the end we do not know how much, how to choose?
Here are two easy ways to teach you:
Method one: check whether the parameters of the eye lamp to achieve the national AA level illumination standards. Generally reach the illumination standard desk lamp, both the illumination or illumination uniformity is relatively up to standard.
Method 2: buy illuminance meter, and then go to the physical shop to measure. This method is relatively more intuitive, but also more reassuring. Test, we put the illuminance meter on the position near the eyes, if the illuminance meter shows that there is still more than 300lux of light, proving that the light environment is suitable for long time reading.
●Colour Temperature When we heat an object, the object will show different colours as the temperature changes. For example, when heating an iron block, the iron block first turns red, then yellow, and finally white, and the temperature corresponding to the colour of the object at this time is the colour temperature, so the colour temperature is strictly speaking actually a temperature measurement method. Therefore, we traditionally think of red and yellow and other “warm colours” is actually low colour temperature, and blue and white and other “cold colours” colour temperature is actually higher.
What is the best colour temperature for eye lamps? Here again, we need to look at the issue from multiple perspectives. A large number of animal experiments have found that long wavelengths of light, such as red and yellow, are more likely to cause the eye axis to grow than short wavelengths of light, such as blue and purple. So from the perspective of delaying myopia, high colour temperature light may theoretically be more appropriate than low colour temperature light.
However, if the colour temperature is too high, the light will appear whiter or even bluer, and some people will feel uncomfortable when exposed to such light for a long time. Therefore, many experts and scholars will be 4000K (Kelvin temperature) around the colour temperature of the light (similar to the sunrise light) as the most suitable for people to read the colour temperature.
It should be noted here that the 4000K (Kelvin temperature) colour temperature is only a recommendation based on “myopia prevention and control”, “brightness”, “comfort” and other considerations. There is still room for individual differences. If someone reads and writes at 5000K colour temperature without any discomfort, there is no need to deliberately lower the colour temperature. The “People’s Republic of China national standards — reading and writing desk lamp performance requirements” in the night is only recommended to choose 4000K (Kelvin temperature) below the colour temperature of the light.
● Blue light in fact blue light and myopia is not too related to the real danger of blue light is long-term exposure will cause some chronic damage to the retina under the eye. International standards classify retinal blue light hazards into four categories: no risk category, low risk category, medium risk category and high risk category, because minors’ crystals are more transparent, and the permeability to blue light will be better. Therefore, when we choose eye protection lamps, it is best to choose no blue light hazard products.
● Can video flash in many of the eye lamps will play “no strobe” gimmick, in fact, this is a concept to steal the beam. Stroboscopic refers to the fluctuation of the luminous flux of the electric light source at a certain frequency, theoretically, all the lights will exist strobe. When the strobe frequency is very low, our human eyes will notice the flicker of light, long-term exposure to such lights will aggravate eye fatigue. And when the strobe is higher than a certain frequency, the human eye will not have any reaction. Therefore, when we buy eye protection lamps, the pursuit of not “no strobe” but “no video flash”. Here is the easiest way to detect, is to take out the mobile phone to open the camera to the light, see whether there is fluctuation.
The colour rendering index (Ra) is a measure of the consistency between the colour of a light source on an object and the colour of the object itself. It simply means that the external light will have a certain effect on our ability to identify the colour of an object, and the colour we see under high Ra lighting is closer to the true colour of the object. Low colour rendering index lighting will not only increase the difficulty of colour recognition, but also increase visual fatigue. Colour rendering index is divided into: Ra50 below for “poor”, Ra50 ~ 70 for “general”, Ra70 ~ 80 for “good”, Ra80 above for “Excellent”. So when choosing eye lamps, choose high colour rendering index products, general colour rendering index is best above 90.
Auxiliary function of the current market, many eye lamps have a lot of auxiliary functions, such as: voice control, intelligent illumination adjustment, a variety of gear switching. These features are just “icing on the cake”, in fact, it is more important to look at the eye lamp “mobility”, choose the head, the lamp can be adjusted up and down, left and right at will eye lamps, so that you can according to the child’s posture, height and indoor lighting at any time to adjust the position of the light, so that the child read and write, the light should be adjusted at any time. Position, so that children have the most adequate and balanced light when reading and writing. In addition, the desk lamp is best placed on the left front, so that when holding a pen to write, will not form a shadow on the paper. Eye lamp from the desktop height should not be too low, generally in the 40 to 60 cm is relatively good.
Protecting your eyesight is not enough to rely on eye protection lamps and traditional desk lamps than, can relatively alleviate eye fatigue caused by prolonged close reading and writing, alleviate myopia. But still can not replace outdoor activities, OK lenses, low concentration atropine, frame glasses and other myopia prevention and control methods. Therefore, do not think that you can relax the management of other eye habits just because you have bought an eye protection lamp.
● Actively participate in outdoor activities and strictly control the time your child spends playing with mobile phones, tablets and other electronic products.
Follow the “20, 20, 20” eye care motto, that is, look at a distance of 20 feet (6 metres) for more than 20 seconds after looking at a distance of 20 minutes in order to relax the muscles inside the eyes, thus relieving visual fatigue.
The sitting posture when writing follows the principle of “one fist, one inch, one foot”, with the upper body kept upright and slightly leaning forward, and the chest kept one fist away from the table; when holding a pen, the hand should be held one inch away from the tip of the pen. The head is upright, naturally leaning forward, and the eyes are about one foot away from the table. The feet are levelled and the shoulders naturally slumped. This protects your eyesight and also puts your body in a comfortable position to study.
● Don’t turn on just one eye light when your child is reading or writing. All the lights in the house must be switched on at the same time, so as to form a sufficient and even light ring mirror, and effectively relieve eye fatigue caused by close-up eye use.