Horrible! In just a few seconds, I almost went blind! The culprit was actually...

Author: Song Run, Children's Hospital Affiliated to Suzhou University

Reviewer: Feng Kehong, Chief Physician, Children's Hospital Affiliated to Soochow University

There is a kind of "toy" called laser pen that has become very popular among children recently. When you press a button, this small "toy" will shoot out a light strip of various colors. But is it really a toy? There are many news reports like "singer attacked by laser pen at concert". There are many cases of children's vision being damaged after being irradiated by laser pen on the Internet.

So, what exactly is a laser pen? What are the hazards of it? Here is some basic knowledge about laser pens for parents.

Laser pointers are commonly known as "laser pens". They are usually used to project light spots or point to objects during work reports, teaching, and tour guides. Monochromatic lasers of different wavelengths are absorbed by different tissues due to photothermal or photochemical effects, which can cause carbonization, gasification, and denaturation of tissues, resulting in local burns and coagulative damage. The accuracy of laser pens can reach the micron level. They are often used in laser cutting, welding, drawing, and other tasks. They can also be used for navigation, long-distance indication, search and rescue, etc. But at the same time, the "lethality" of laser pens is also quite extraordinary. Laser pens that are as thick as a finger and as long as a finger can cause blindness if used improperly during play!

Xiaoliang, 14 years old this year, has suffered permanent damage to his eyesight because he secretly played with his father's laser pen. Xiaoliang's father has a laser pen, and Xiaoliang secretly shone it into his eyes for 3 days, then found that he could not see clearly. Xiaoliang's parents rushed him to the hospital's ophthalmology department for treatment. The doctor diagnosed that Xiaoliang's eyes were burned by the laser pen, causing the macular degeneration of both eyes, and the vision of both eyes was only 0.1-0.2.

At the same time, recently there were cases where elementary school students were taking science classes and the teacher distributed laser pens for science teaching. The students shone the laser pens on each other, causing vision damage.

Figure 1 Copyright image, no permission to reprint

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How powerful is a laser pointer?

According to the laser level classification of the National Standard of the People's Republic of China - Safety of Laser Products (GB7424.1-2012), different levels of laser danger vary. Starting from Class 2, long-term laser exposure to the eyes will cause damage to the eyes, not to mention the highest level of lasers. Even for a moment, laser exposure to the eyes will be dangerous.

Figure 3 Copyright image, no permission to reprint

So, how does a laser pen affect vision? Laser pens can easily cause damage to the macular area.

Functional damage, in severe cases may cause blindness. The macula is located in the center of the retina and is the most sensitive area for vision. The macula has dense retinal pigments and is easily absorbed by the laser energy, thus being damaged by the laser thermal radiation. Any damage involving the macula will cause a significant decrease in central vision, dark and distorted vision, etc.

The harm of laser pens to the eyes is mainly caused by its thermal effect. The laser passes through the cornea to reach the retina at the fundus. The outermost pigment epithelium of the retina contains more melanin, which has a significant absorption effect on the laser. If a certain amount of heat is generated, it will burn the retina and cause vision loss. Many laser pens sold on the market belong to Class 3B, with a power of more than 5mW. If the laser is directly shot into the eye, it will be absorbed by the pigment epithelium of the fovea. Therefore, some high-power laser pens can even cause macular holes.

Many students particularly like to play with laser pens. At the same time, some science classes also have teachers using laser pens to conduct scientific experiments. However, some naughty students often like to shine laser pens into each other's eyes, not knowing that this is a very dangerous behavior.

Although "laser pens" have long been removed from the list of toys, they still appear around children. For example, laser pens used in speech teaching, laser banknote detectors, laser rangefinders, etc. There are even industrial-grade laser pens for sale. When they are sold online, their harmfulness is usually not explained in detail, so they can easily be used as toys by children.

At the same time, there are many laser pens for sale around the school, such as in stationery stores. Most of them are "three-no products" and have no laser grade marked, which poses a great safety hazard. According to the laser grade classification of laser product safety (GB7424.1-2012), only Class 1 laser products are safe, but they cannot be used for fun.

Therefore, if parents need to buy laser pens, whether for themselves or for their children, they must buy regular products produced by qualified manufacturers (no more than Class 2 laser level). At the same time, be sure to store the laser pen where children cannot reach it, and play with it under the guidance of parents when necessary. If you are injured by laser, go to the hospital immediately.