Laser pointer for cats: fun and danger in one bottle. Harm of laser hair removal: truth or myth Laser eye pointer

"Don't look at the welding, you'll go blind!" Each of us at least once heard this phrase from our parents, and probably said it to our own. “You can’t shine a laser pointer in your eyes!”, “You can’t enter a room with a quartz lamp on!” - too. How substantiated these statements are, MedAboutMe will try to figure it out.

The eyes of a person, and of other mammals and birds too, are a wonderful biological device, an optical device that allows us to see.

Separates the contents of the eye from the outside world lenticular transparent cornea. Together with the opaque sclera, it makes up the first shell of the eye. The cornea performs functions comparable to a window in a house: light enters the organ of vision through it.

The second choroid includes the iris, its anterior part, as well as the ciliary body and choroid - the middle and back parts. The iris not only determines the color of the eyes, but also acts as a diaphragm: the pupil located in the center of the iris narrows or expands depending on the degree of illumination, adjusting the beam of light entering the eye.

Inside the ciliary body there is also a small, but very important accommodative muscle for visual acuity. It is on her that the ability of the eye to see both distant and close objects depends, since it changes the shape of the lens - a natural lens.

The back of the choroid is called the choroid. It nourishes the third shell: the retina.

The retina includes several layers of nerve cells of a special type, which, in fact, provide the ability of the eye to see. In these cells, the light is converted into an electrical impulse that is transmitted by the optic nerve to the brain, which recognizes and interprets the received signals. Visual cells are of two types: "rods" and "cones". Their main part is located in the central part of the retina, in the macula.

The ability of the eye to see depends on the work of all its constituent parts, all its departments. Violation of the functions of any of the departments leads to deterioration or loss of vision. This condition may be temporary or permanent, irreversible.

The danger posed by a quartz lamp, welding and laser emitters is not the same. A quartz lamp is a source of ultraviolet radiation, under the influence of which the tissues of the eye develop. The likelihood of recovery from this type of injury depends on the extent of the injury. Mild to moderate burns can be treated by restoring the ability of the eye to see. Severe burns leave behind permanent damage that significantly reduces visual acuity or even causes blindness.

Electric welding emits infrared and ultraviolet radiation, which can also cause damage to the eyes, from a slight burn of the cornea to damage to the retina.

Burns from ultraviolet and infrared radiation are not felt immediately, but after a few hours, causing pain, swelling, profuse lacrimation, photophobia.

Otherwise, the laser beam operates. Possessing a high penetrating power and a high energy density in the cross section of the beam, the laser penetrates into the deep structures of the eye and destroys the sensitive nerve cells of the retina, and irrevocably. Pain is not felt.

The degree of danger of a laser is determined by many of its characteristics. Some lasers do not pose a danger because, due to their relatively long wavelength and low power, they are not able to penetrate the outer shells of the eye. Others penetrate even through optically opaque materials impervious to infrared and ultraviolet radiation.

There is a classification of lasers according to the degree of danger, from the first degree, which is practically safe for the eyes and body, to the fourth, which includes devices of high power and radiation density that can cause damage not only to the sensitive structures of the eye, but also to human skin. Class 4 lasers are even capable of igniting combustible materials, while Class 1 and 2 devices are dangerous only under certain, unlikely conditions. Hazard class 2 includes, in particular, laser scanners of cash registers and recognition devices.

As already mentioned, class 1 and 2 lasers are practically safe. To the first class belongs, for example, the family of laser mice. Their power is so small that they do not pose a danger. Laser barcode scanners are class 2. The beam from them can be seen only under certain conditions. The source of radiation can cause damage to the organs of vision only if the beam continuously affects the retina from a minimum distance for at least 30 seconds. Class 2a lasers are installed and fixed in such a way that accidental eye contact with the beam is completely excluded. This is the radiation source in DVD-ROM, for example.

The third class is divided into two subclasses. 3a lasers are dangerous, but you can close your eyes with minimal damage. A radiation source of class 3b is certainly dangerous, you don’t have time to close your eyes, it burns even the skin. Such sources are installed in CD-ROM, laser printers. The danger is also increased by the fact that the beams of these lasers are invisible. You can lose your sight without noticing the source of danger.

Dangerous class 3b includes any laser whose beam is visible without fog and smoke from the side, as well as all powerful laser pointers and, in general, all sources more powerful than 5mW. Such lasers, unfortunately, are often used in clubs and discos to create visual effects. In doing so, they often head straight for the crowd.

All cutting lasers belong to the very dangerous fourth class.

In the summer of 2008, about 30 people, participants of the Aquamarine festival, lost their sight. They received serious and irreversible retinal injuries caused by a laser used during the show.

The entertainment industry has been using lasers for many years, and this equipment is quite affordable. Sometimes it is purchased by people who do not have a clue about safety regulations.

Cases of vision loss as a result of laser burns were also in other cities, although not so massive.

A home quartz lamp refers to devices whose benefits are ambiguous when used in everyday life. The constant quartzization of residential premises creates too sterile conditions in which the immune system weakens as unnecessary. In addition, quartzization is accompanied by the synthesis of toxic ozone. After turning off the lamp, it is necessary to ventilate the room well.

• Do not turn on the lamp indoors if there are people or animals in it. If a child is irradiated for medical reasons, then the procedure should take place in protective goggles with high UV protection.
• The switch must be located so that the child under no circumstances could turn on the lamp himself.

Accidental eye burns are unpleasant, painful, but disappear in a few days. Severe injuries can lead to damage to the deep structures of the organ of vision and blindness. Probably the development of cataracts.

Welding

Radiation hazardous to the eyes is generated by electric welding. Professional welders are well aware of what an "eye burn" is. They call this state "caught bunnies." This happens sometimes even with experienced welders, and even with safety violations by absent-minded or inexperienced workers, this happens more often. In medicine, there is even a special term for an eye burn by electric welding: electrophotophthalmia.

A mild to moderate burn is very uncomfortable, but usually resolves in a few days. The conjunctiva may redden and swell, lacrimation intensifies, the cornea becomes cloudy.

Severe electric welding burns cause the affected tissue to die. The cornea becomes cloudy, loses its transparency, films form on the conjunctiva that cannot be separated and removed.

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Harmful bacteria can get into the affected tissues. If treatment is not started on time, the likelihood of an unfavorable course of the disease will increase sharply, up to a complete and final loss of vision.

Professionals protect their eyes and face with masks, the glass of which has special properties and does not transmit UV and IR radiation.

Of course, the child does not have such a mask, and the bright spark and crackling of the welding machine will certainly attract the attention of the baby. Parents should explain from early childhood why it is impossible to look at welding with unprotected eyes. If this does happen, the child should be taken to the emergency room immediately. Timely treatment will relieve with a high degree of probability not only from the consequences of the injury, but also from its painful and very unpleasant symptoms.

A new study, featured in HealthDay, has found that laser pointers may look harmless, but when children play with them, they can result in blurry vision, blind spots, or possibly even permanent vision loss. A report on this study was published on September 1, 2016 in the journal Pediatrics.

Laser pointers are dangerous, but too affordable

The new study examined in detail the cases of four children aged between nine and 16 whose foolish jokes with laser pointers caused traumatic damage to the retina (the light-sensitive tissue that lies at the back of the eye and is essential for clear vision).

Study author Dr. David Almeida, an ophthalmologist in private practice in Minneapolis, says eye damage from laser pointer light is on the rise. Previously it was thought to be a one in a million occurrence and that it was probably such a rare and unusual reaction, but as Dr. Almeida points out, this is never a reaction.

The study says that mislabeling of laser pointers, which are typically sold in office supply stores and online stores, may be part of the problem.

Previous research has shown that a significant percentage of red and green laser pointers are labeled as having an output power of between one and five milliwatts, which is supposedly safe for the eyes. But during the study, it was found that these devices have an output power of more than five milliwatts.

Charles Wykoff, MD, PhD, deputy head of the department of ophthalmology at the Blanton Eye Institute at Houston Methodist Hospita, says availability of laser pointers is increasing and they are now easy to order online which makes it difficult to control.

Dr. Wyckoff was not involved in the new study, but in his own practice he has seen two cases of laser pointer damage to the retina. He notes that no one knows exactly how much power the purchased device has.

In the new study, Dr. Almeida and his team took a detailed look at the cases of four boys whose vision was damaged when they looked directly, either directly at a beam from a laser pointer or directly at a beam reflected from a mirror. The resulting damage to the retina caused acute, one might say, dramatic symptoms. As the expert explains, these symptoms include blurry, distorted vision, or even loss of central vision.

Dr. Almeida, who has treated these four children for two years of his practice, says that when it comes to the retina, it's all about where the laser pointer hits. If the laser strikes the eye at an angle, you may even notice nothing, since everything will be completely asymptomatic. But if the laser beam strikes the center of the eye, one can lose sight immediately and never recover.

Dr. Almeida and Dr. Wyckoff note that there are very few known treatment options for retinal damage caused by a laser pointer beam. In case of complications following an injury, surgery may be required, but in most cases this can only be controlled by observation.

Dr. Wyckoff says that some ophthalmologists may prescribe corticosteroids to patients to reduce inflammation inside the eye, but due to the lack of human studies, this option is considered controversial.

Three of the four children in Dr. Almeida's study suffered from potentially permanent vision loss. The Doctor encourages adults such as healthcare professionals, teachers and parents to educate children about the dangers of laser pointers and discourage or limit their use.

When marking laser pointers, you must indicate that they are dangerous to the eyes.

Dr. Almeida says it's important to be aware that laser pointers can cause serious, permanent vision loss if used incorrectly. He also notes that regulation of the use of pointers is probably still beyond reasonable limits, but given the number of injuries, these devices represent a serious and preventable public health problem.

Dr. Wyckoff adds that you should not look directly at the laser pointer beam, you should not direct it into your own eyes and into the eyes of other people. In fact, after an injury has been received, there is very little that can be done. He also notes that laser pointers need to be properly labeled so that users can avoid problems that can arise from misuse and underestimation of their potential danger. It must be pointed out that no laser pointer is safe for the eyes.

According to Health Day

Technology is developing at an incredible pace. A few decades ago, a laser seemed like a fantasy, but today a laser pointer can be bought literally for a penny at a street kiosk.

But while lasers are increasingly becoming part of everyday life, it is worth remembering that careless handling of them is fraught with serious troubles. In this review, from the dangers that lasers carry.

1. Embarrassed and burned

Doctors at Tokyo Medical University Hospital were performing surgery on a 30-year-old patient's cervix when she suddenly passed gas. In the laser beam, the gases ignited, causing the surgical drape to catch fire, and then the fire quickly spread to the woman's waist and legs. The committee investigated the incident and concluded that all equipment was in good working order and used properly, it was just an accident.

2. Five people per day

At the West Laser and Cataract Surgery Center (West Springfield, Massachusetts), five patients suffered severe eye injuries from injections of anesthesia prior to laser eye surgery. On the very first day of his work, Dr. Cai Chiu managed to harm the unfortunate patients. Center West's management said he either lied about his level of aptitude or didn't have proper knowledge of the equipment. Chiu has since retired and been banned from practicing medicine in the US.

3. Accident on the road

A woman from Albany, Oregon, was driving her husband to work when she was suddenly blinded by laser light. Miranda Centers was temporarily blinded by a laser beam and crashed into a barrier. One of the drivers shone a laser pointer into the eyes of the other. As a result, this led to several accidents on the highway.

4. Up to five milliwatts!

After an increase in the number of accidents of aircraft and helicopters associated with laser pointers, the UK decided to crack down on dangerous devices. In most countries, lasers up to five milliwatts are considered safe. However, despite all the UK bans, some high performance class 3 lasers are freely available online. More than 150 eye injuries have already been reported due to these devices.

5. US Air Force Shoot Down UAVs

In June 2017, the US Army successfully tested laser guns mounted on Apache helicopters. According to manufacturer Raytheon, this was the first time that a fully integrated laser system aboard an aircraft has successfully acquired and fired at targets over a wide range of flight modes, altitudes and speeds. The weapon has a range of about 1.5 km, is silent and invisible to people. They are also extremely accurate. The Army plans to use similar lasers to defend against any future drone attacks.

6. Pursuit of a football player

In 2016 in Mexico City, during an international NFL game between the Houston Texans (USA) and the Oakland Raiders (New Zealand), Texans guard Brock Osweiler was harassed by some negligent fan. Every time Osweiler received the ball, one of the spectators shone a green laser pointer in his face so that the player did not see where to run.

7. The viability of the power supply of cars

Despite the millions of dollars spent on the development of self-driving cars, one security researcher was able to ask serious questions about their viability in the near future. The scientist was able to interfere with the laser sensors of an unmanned vehicle by simply shining a cheap laser pointer on them. The car's system considered this an "invisible obstacle" and slowed the car to a complete stop.

8. Traumatic liposuction

During the laser liposuction procedure, one of the patients received severe burns, and after that the clinic management tried to dissuade her from treatment. Dr. Muruga Raj instead told her that it was all right, nothing to do with the burn, but just smear the affected area with cream. In the end, the case went to court.

9. Laser pointer and helicopter

Connor Brown, 30, only found out about it when he was charged. A police helicopter was looking for the man who had caused a riot in the park when Brown aimed a laser pointer at him in the cockpit. Both crew members were blinded and the mission had to be aborted to take the police to the hospital. Brown eventually called his act "a terrible mistake for which there is no excuse."

10. Burnt fingers

The Australian wanted to remove some of the tattoos from the knuckles, but ended up with severe burns. The doctor said he would need ten to twelve sessions of $170 laser surgery to remove "Live Free" from his fingers, but an anonymous human patient started asking questions after nearly 20 sessions failed to produce the desired results. The doctor tried to speed things up a little and set the laser machine to that very high power. As a result, the fingers burned 3 mm.

Lasers and radiation from them have been used by mankind for quite a long time. In addition to the medical environment, such devices are widely used in technical industries. They were adopted by specialists from the field of decorating and creating special effects. Now, not a single large-scale show is complete without a stage with laser beams.

A little later, such radiation ceased to take only industrial forms and began to occur in everyday life. But not everyone knows how the effect of laser radiation on the human body is reflected with regular and periodic exposure.

What is laser radiation?

Laser radiation is born according to the principle of creating light. In both cases, atoms are used. But in the situation with lasers, there are other physical processes, and the influence of an external electromagnetic field is traced. Because of this, scientists call the radiation from lasers forced or stimulated.

In the terminology of physics, laser radiation is called electromagnetic waves that propagate almost parallel to each other. Because of this, the laser beam has a sharp focus. In addition, such a beam has a small scattering angle, together with a huge intensity of influence on the surface that is irradiated.

The main difference between a laser and a standard incandescent lamp is the spectral range. The lamp is considered a man-made light source that emits electromagnetic waves. The lighting spectrum of a classic lamp is almost 360 degrees.

The impact of laser irradiation on all living things

Contrary to stereotypes, the effect of laser radiation on the human body does not always mean something negative. Due to the widespread use of quantum generators in various areas of life, scientists decided to use the capabilities of a narrow beam in medicine.

In the course of numerous studies, it became clear that laser irradiation has several characteristic properties:

• Damage from a laser can be produced not only in the process of direct exposure to the body from the apparatus. Even scattered radiation or reflected rays can cause damage.
• There is a direct relationship between the degree of damage and the main parameters of the electromagnetic wave. The location of the irradiated tissue also affects the severity of the lesion.
• The negative effect of energy absorption by tissues can be expressed in thermal or light exposure.

But the sequence in case of laser damage always provides for an identical biological principle:

• an increase in temperature, which is accompanied by a burn;
• boiling of interstitial and cellular fluids;
• the formation of steam that creates significant pressure;
• explosion and shock wave destroying all tissues nearby.

Often, an incorrectly used laser emitter is, first of all, a threat to the skin. If the influence was especially strong, then the skin will look edematous, with traces of numerous hemorrhages. Also on the body there will be large areas of dead cells.

Such irradiation also affects internal tissues. But with large-scale internal lesions, the scattered effect of the rays is not as strong as the direct or reflected mirror effect. Such damage will guarantee pathological changes in the functioning of various body systems.

The skin that suffers the most is the protection of the internal organs of each person. Because of this, he takes most of the negative impact on himself. Depending on the different degrees of damage, redness or necrosis will appear on the skin.

The researchers concluded that dark-skinned people are less susceptible to deep-seated lesions due to laser irradiation.

Schematically, all burns can be divided into four degrees, regardless of pigmentation:

• I degree. It implies standard burns of the epidermis.
• II degree. Includes burns of the dermis, which is expressed in the formation of characteristic blisters of the surface layer of the skin.
• III degree. Based on deep burns of the dermis.
• IV degree. The most dangerous degree, which is characterized by the destruction of the entire thickness of the skin. The lesion covers the subcutaneous tissue, as well as the layers adjacent to it.

Laser eye lesions

In second place in the unspoken rating of the possible negative effects of the laser on the human body are lesions of the organs of vision. Short laser pulses can disable in a short period of time:

• retina,
• cornea
• iris,
• lens.

There are several reasons for such an impact. The main ones are:

• Inability to respond in time. Due to the fact that the pulse duration is no more than 0.1 seconds, a person does not have time to blink. Because of this, the eye remains unprotected.
• Slight vulnerability. According to their characteristics, the lens and cornea are considered vulnerable organs in themselves.
• Optical eye system. Due to the focusing of laser radiation on the fundus, the irradiation point, when it hits a retinal vessel, can clog it. Since there are no pain receptors there, damage cannot be detected instantly. Only after the scorched area becomes larger, the person notices the absence of part of the image.

To quickly navigate with a potential lesion, experts advise listening to the following symptoms:

• eyelid spasms,
• eyelid edema,
• pain sensations,
• retinal hemorrhage,
• turbidity.

The danger is added by the fact that laser-damaged retinal cells lose the ability to recover. Since the intensity of radiation affecting the organs of vision is lower than the identical threshold for the skin, doctors are calling for caution.

You should beware of infrared lasers of various types, as well as devices that generate radiation with a power of more than 5 mW. The rule applies to equipment that produces rays of the visible spectrum.

Relationship between laser wave and its scope

Each of the areas of application of laser radiation is guided by a strictly defined wavelength indicator.

This indicator directly depends on nature. Rather, from the electronic structure of the working fluid. This means that the medium where the generation of its radiation takes place is responsible for the wavelength.

There are different types of solid-state and gas lasers in the world. The beams involved must be one of the three most common types:

• visible,
• UV,
• infrared.

In this case, the operating range of irradiation can vary from 180 nm to 30 mnm.

Features of the effect of a laser on the human body are based on the wavelength. So, for example, a person responds faster to a green laser than to a red one. The latter is not safe for all living things. The reason lies in the fact that our vision perceives green almost 30 times better than red.

How to protect yourself from the laser?

In most cases, protection from laser radiation is needed by those people whose work is closely related to its constant use. If an enterprise has any type of quantum generator on its balance sheet, then its managers must instruct their employees.

Experts have developed a separate set of rules of conduct and safety that will protect the employee from the possible consequences of radiation. The main rule is the availability of personal protective equipment. Moreover, such funds can differ dramatically depending on the predicted degree of danger.

In total, the international classification provides for the division into four hazard classes. The appropriate marking must be provided by the manufacturer. Only the first class is considered relatively safe even for the organs of vision.

The second class includes direct-type radiation that affects the organs of the eyes. Mirror reflection is also included in the presented category.

Radiation of the third class is much more dangerous. Its direct effect threatens the eyes. Diffuse-type reflected radiation at a distance of 10 cm from the surface is no less dangerous. Skin lesions will occur not only with direct exposure, but also with mirror reflection.

In the fourth grade, both the skin and the eyes suffer from various exposure formats.

Collective protective measures at work include:

• special covers,
• protective screens,
• light guides,
• innovative tracking methods,
• alarm,
• blocking.

Of the relatively primitive, but effective methods, the fencing of the zone where irradiation is performed is distinguished. This will protect workers from accidental exposure through negligence.

Also, at especially dangerous enterprises, it is mandatory to use personal protective equipment for employees. They mean a special set of overalls. You can’t do without wearing goggles that provide a protective coating during work.

Laser gadgets and their radiation

Many are unaware of how serious the consequences of the uncontrolled operation of home-made devices with a laser principle can be. This applies to home-made structures like laser ones:

• lamps,
• pointer,
• flashlights.

This is especially true for high school students who seek to conduct a series of experiments without having an idea about the safety rules when designing them.

It is unacceptable to use home-made lasers in rooms where people are present. Also, do not direct the rays at glass, metal buckles and other objects that can give reflections.

Even if the beam is of low intensity, it can lead to tragedy. If you point the laser at the driver's eyes during active movement, he may go blind and lose control.

Under no circumstances should you look into the lens of the laser source. Separately, it should be taken into account that glasses for working with a laser must be designed for the wavelength that the selected devices will generate.

In order to prevent a serious tragedy, doctors are asked to listen to these recommendations and follow them at all times.