"Doctor, is the eye lamp useful, which brand is better to buy?" I believe that many parents have asked doctors such questions during the eye clinic. Regarding whether eye protection lamps are useful, there are currently two extreme views, some manufacturers will over-exaggerate the efficacy of eye protection lamps, publicizing that as long as a certain brand of eye protection lamps is used, it can play a very good role in myopia prevention and control, and more merchants even compare the myopia prevention and control effect of eye protection lamps with OK mirrors (orthokeratology glasses) and glasses. On the other hand, some ophthalmologists have devalued eye lamps to nothing, saying that "all eye lamps on the market are IQ taxes and have no effect." There is time and energy to pick up eye lamps for children, it is better to take children to outdoor activities. "In fact, the different statements about eye protection lamps, we need to look at it dialectically.
Is it necessary to buy eye lamps The most effective light for the prevention and control of myopia known at present is sunlight, outdoor light can promote the release of intracranial dopamine, and dopamine can effectively inhibit myopia and achieve the purpose of preventing myopia. It can be said that the sun is currently confirmed to be the only "eye lamp" that can effectively prevent and control myopia. Since sunlight is composed of ultraviolet light (UVR, wavelength below 400 nm), visible light (VIS, wavelength 380 ~ 760 nm) and infrared light (IR, wavelength 760 nm or more), there is no artificial lamp on the market that can simulate the effect of sunlight alone.
However, with the progress of the times, human living habits have long been different from the ancestors' "sunrise and sunset", most children still have to read, write and other close-up eye activities after the sun goes down. At this time, in the absence of sunlight, the selection and use of artificial light is particularly important. Therefore, in the absence of sufficient sunlight, choosing an eye lamp can indeed delay the impact of long-term close-up use on the progress of myopia. Therefore, eye protection lamps are still needed.
There are many professional terms on how to choose eye protection lamp eye protection lamp, resulting in many parents being confused when choosing. You can refer to the following indicators:
●A large number of clinical experimental studies of illuminance have proved that the brighter the surrounding environment, the slower the growth rate of the eye axis. Professor Yang Zhikuan of the Optometry Group of the Chinese Medical Association reminded: "When children read and learn at home, the value of the incoming eye light should not be less than 125 lux (lighting unit, hereinafter referred to as lux), which is also an important factor that cannot be ignored when preventing children's myopia." According to the "People's Republic of China Primary and Secondary School Classroom Lighting and Lighting Hygiene Standards" jointly issued by the Ministry of Health and the Standardization Management Committee, the surface illumination of classroom desks is not less than 300lux, and the illumination of classroom blackboard is not less than 500lux. The international lighting code CIES008/E-2001 requires 500lux for office environments, school environments, and library reading environments.
In addition, illuminance uniformity is also one of the criteria for judging the quality of eye lamps. Illuminance uniformity refers to the ratio of the minimum illuminance to the average illuminance on a specified surface. The closer the illuminance uniformity is to 1, the more evenly distributed the light and the more comfortable the eyes will be when used.
The illuminance marked in the introduction of many eye protection lamp products is measured from the edge of the light source, and the actual illumination and illumination uniformity of the eyes are not known, so how to choose?
Here are two simple ways to teach you:
Method 1: Check whether the parameters of the eye lamp meet the national AA-level illuminance standard. Generally speaking, table lamps that meet the illuminance standard, whether it is illuminance or illuminance uniformity, are relatively up to standard.
Method two: buy a lux meter, and then go to the physical store to test. This method is relatively more intuitive and more reassuring. When testing, we place the illuminance meter near the eye, and if the illuminance meter shows that there is still more than 300 lux of illuminance, it proves that the illumination environment is suitable for reading for a long time.
● Color temperature When we heat an object, the object will show different colors with temperature changes. For example, when heating an iron block, the iron block first becomes red, then yellow, and finally becomes white, at this time the temperature corresponding to the color of the object is the color temperature, so the color temperature is strictly speaking, it is actually a temperature measurement method. Therefore, the "warm colors" such as red and yellow that we have traditionally thought are actually low color temperatures, while the "cool colors" such as blue and white are actually higher.
How many color temperature eye care lamps are generally selected? Here we have to look at the problem from multiple angles. A large number of animal experiments have found that red and yellow iso-wavelength rays are more likely to cause eye axis growth than blue, purple and other short-wavelength rays. Therefore, from the perspective of delaying myopia, high color temperature light may theoretically be more suitable than low color temperature light.
However, if the color temperature is too high, the light will appear whiter or even bluer, and some people will feel harsh discomfort when exposed to such light for a long time. Therefore, many experts and scholars regard the illuminance of the color temperature of about 4000K (Kelvin temperature) (similar to the light at sunrise) as the most suitable color temperature for people to read.
It should be noted here that the 4000K (Kelvin temperature) color temperature here is only a comprehensive suggestion given from many aspects such as "myopia prevention and control", "brightness" and "comfort", so individual differences are allowed. If someone reads and writes at 5000K color temperature without any discomfort, there is no need to deliberately lower the color temperature. The "National Standard of the People's Republic of China——— Reading and Writing Desk Lamp Performance Requirements" only recommends that you choose a color temperature below 4000K (Kelvin temperature) at night.
● Blue light In fact, blue light and myopia do not have much to do with each other, and the real harm of blue light is that long-term exposure will cause certain chronic damage to the retina of the fundus. International standards divide the retinal blue light hazards into 4 levels: no hazard, low hazard, medium hazard and high risk, because the lens of minors is more transparent and the transparency of blue light will be better. Therefore, when we choose eye protection lamps, it is best to choose products without blue light hazards.
● But video flash now a lot of eye lamps will play a "no stroboscopic" gimmick, in fact, this is a concept of stealing beams and changing columns. Stroboscopic refers to the fluctuation of the luminous flux of the electric light source at a certain frequency, and theoretically all lamps will have stroboscopic. When the frequency of strobe is very low, our human eyes will perceive the flickering of light, and long-term exposure to such light 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 lamps, the pursuit is not "no strobe" but "no video flash". Here is the simplest way to detect, is to take out the phone and turn on the camera and turn on the light to see if there is any fluctuation.
● Color rendering index Color rendering index (Ra) refers to a measure of the color of the light source on the object and the color consistency of the object itself. Simply put, the lighting of the outside world will have a certain impact on the color of the object we distinguish, and the color of the object we see under the high color rendering index light is closer to the real color of the object. Lights with low color rendering index will not only increase the difficulty of color identification, but also increase eye fatigue. The color rendering index is divided into: Ra50 below the "poor", Ra50 ~ 70 is "general", Ra70 ~ 80 is "good", Ra80 above the "excellent". Therefore, when choosing an eye lamp, it is necessary to choose a product with a high color rendering index, and the general color rendering index is preferably above 90.
● Auxiliary functions Many eye care lamps on the market at present have many auxiliary functions, such as: voice voice control, intelligent illumination adjustment, and various gear switching. These functions are only "icing on the cake", in fact, more important is the "mobility" of the eye lamp, choose the lamp head, the lamp pole can be adjusted up and down left and right at will, so that the position of the light can be adjusted at any time according to the child's posture, height and indoor light, so that the child has the most adequate and balanced light when reading and writing. In addition, the table lamp is best placed in front of the left, so that when you hold a pen and write, you will not form a shadow on the paper. The height of the eye lamp from the desktop should not be too low, generally at 40 to 60 cm is relatively good.
Protecting vision alone by eye lamps is not enough to protect the eyes of lamps and traditional table lamps, which can relatively alleviate eye fatigue caused by long-term close reading and writing, and alleviate myopia. However, it is still not a substitute for myopia prevention and control methods such as outdoor activities, OK glasses, low-concentration atropine, and glasses. Therefore, we must not think that buying an eye lamp can relax the management of other eye habits.
● Actively participate in outdoor activities and strictly control children's time playing with electronic products such as mobile phones and tablets.
● Follow the "20, 20, 20" eye protection tips, that is, watch for nearly 20 minutes and gaze at a distance of 20 feet (6 meters) for more than 20 seconds, so that the muscles in the eyes can be relaxed, thereby relieving eye fatigue.
● The sitting posture when writing follows the principle of "one punch, one inch, one foot", the upper body remains upright, can lean forward slightly, and the chest is kept one fist away from the table; when holding the pen, the hand should be held at a position one inch away from the tip of the pen. The head is upright, naturally leaning forward, and the eyes are about a foot away from the tabletop. The feet are flattened and the shoulders are naturally sagging. In this way, it protects the eyesight and also allows the body to be in a comfortable state to learn.
● When reading and writing, do not just turn on an eye lamp. The headlights at home must be turned on at the same time, so as to form a sufficient and uniform light ring mirror, effectively alleviating eye fatigue caused by close-range eyes.
Source: Popular Science China