Home » In-depth analysis | Why LED lights hurt the eyes

In-depth analysis | Why LED lights hurt the eyes

by nadlia
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LThere are many research reports and reports on LED lights on the Internet, but most of them talk about a lot of terms and concepts, and it is a bit difficult for ordinary people to read. This article has read a lot of information, omitting some concepts that can be avoided, making it easier for readers to understand the harm of LED lights and blue light to people.

This article mainly discusses LED lights, but there are many things to pay attention to in the application of ordinary lights in real life, which are mentioned in “What are the precautions for indoor lights” on www.nada2.com.

The difference between incandescent and LED lights

The light-emitting principle of an incandescent lamp is that after the current passes through the tungsten wire, the temperature of the tungsten wire rises sharply to become incandescent, and then emits light. When an incandescent lamp of about 40W emits light, the temperature of the tungsten wire can reach 3000°C to 4000°C. The spectral distribution of incandescent lamps is similar to that of sunlight. Although it also produces blue light, it is much less than LED lamps, so it generally does not hurt the eyes. However, the disadvantages of incandescent lamps are also obvious, such as low electro-optical conversion rate and serious energy consumption. Therefore, in 2016, China has banned the import and sale of incandescent lamps of 15W and above.

Most LED lights emit blue light through the chip, which excites yellow phosphors to reconcile into white light. Although the advantage of LED lamps is the high electro-optical conversion rate, it is an ideal energy-saving lamp. But there is more blue light in the spectrum emitted by the LED, especially the LED has a strong blue light near the wavelength of 450nm, which is very different from the solar spectrum.

The dangers of night lights

Leaving aside the dangers of blue light, the lights at night are harmful to a certain extent. In fact, artificial light sources are more or less harmful to human eyes, but only to a certain extent. Research at Harvard University has shown that long-term exposure to light at night increases the risk of cancer (breast, prostate), diabetes, heart disease, and obesity. Although the mechanism is not fully understood, it is known that exposure to light at night suppresses the secretion of melatonin, causing disruption of normal body rhythms, with some experimental evidence (albeit very preliminary at this point) , lowered melatonin levels may be linked to these conditions.

The dangers of blue light

Blue light hazard refers to the 400-500nm blue light band of the light source. If the brightness is too high, the eyes may cause photochemical damage to the retina if the eyes look directly at the light source for a long time. Experimental studies on mice and rhesus monkeys with blue light have shown that blue light can cause long-term photochemical damage to the retina, inhibit cell metabolism, and prevent the body from providing nutrients to photoreceptors, leading to malignant transformation of the retina. 403nm blue light can damage the photoreceptor cells of the eyes.

Although there is currently no experiment on the damage of LED lights to human eyes (who dares to do it), some ophthalmologists said that long-term exposure of the eyes to blue light or strong light will damage the macula of the eyes, leading to macular degeneration and other problems. Can affect vision. The degree of blue light hazard depends on the cumulative dose of blue light received by the human eye under the light.

People in need of special attention

The first category is infants with delicate eyes, because the lenses of infants are clearer and unable to filter blue light, and children have the nature of chasing light. Long-term exposure to large amounts of blue light will cause phototoxic damage to the retina of infants and affect vision.

The second category is diabetics, because after years of development of diabetes, there are retinal lesions, and the approximate value of retinal light damage is greatly reduced, and blue light has a greater impact on their vision.

suggestion

The color temperature of LED lights used indoors should not exceed 4000K, and LED lights with a color temperature of 5000K and above should be avoided, because the higher the color temperature, the greater the possibility of blue light overflow, and the damage to the colloid of the lamp beads will also cause blue light overflow.

Reasonable arrangements for surfing the Internet or wearing glasses with anti-blue light function can also avoid the damage of blue light to the eyes.

Qualified LED lamps can generally be used with confidence, but you must purchase regular brand LED lamps through regular channels. Eye protection lamps are completely nonsense, so don’t buy them.

For desk lamps, my personal suggestion is to try not to choose LED lamps. After all, desk lamps have a high usage rate, and it is very troublesome to read or do homework when using them.

ps: The pictures are not LED lights.

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