A new study reported in HealthDay finds that laser pointers may look harmless, but when children play with them, they can result in blurred vision, blind spots or perhaps even permanent vision loss. The report of this study was published September 1, 2016 in the journal Pediatrics.

Laser pointers are dangerous but too affordable to buy

A new study closely examined the cases of four children, aged nine to 16, whose foolish pranks with laser pointers caused traumatic damage to the retina (the light-sensitive tissue at the back of the eye that is critical to clear vision).

Study author Dr. David Almeida, an ophthalmologist in private practice in Minneapolis, said cases of eye damage from laser pointer light are becoming more common. It was previously thought that this happened in one case in a million and that it was probably such a rare and unusual reaction, but as Dr. Almeida points out, it is never a reaction.

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

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

Charles Wykoff, MD, PhD, vice chair of ophthalmology at the Blanton Eye Institute at Houston Methodist Hospita, says laser pointers are becoming more widely available and can now be easily ordered online. , which complicates the ability 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 what power output the purchased device has.

In the new study, Dr. Almeida and his team closely examined the cases of four boys whose vision was damaged when they looked directly, either directly at the beam coming from a laser pointer or directly at the 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 blurred, distorted vision or even loss of central vision.

Dr. Almeida, who treated these four children during his two years of practice, says that when it comes to the retina, it's all about where the laser pointer hits. If the laser hits the eye at an angle, you may not even notice anything, since everything will be completely asymptomatic. But if the laser beam hits the central part of the eye, you may lose your vision immediately and never recover.

Dr. Almeida and Dr. Wyckoff note that there are very few known treatment options for retinal damage caused by laser pointer beams. Complications following the injury may require surgery, but in most cases this can only be managed through observation.

Dr. Wyckoff says 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 potentially permanent vision loss. The doctor urges adults such as health care professionals, teachers and parents to educate children about the dangers of laser pointers and discourage or limit their use.

When marking laser pointers, it is necessary to indicate that they are dangerous to the eyes.

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

Dr. Wyckoff adds that you should not look directly at the beam emanating from a laser pointer, you should not direct it into your own eyes or into the eyes of other people. In reality, once an injury has occurred, there is very little that can be done. He also notes that laser pointers need to be properly labeled so that consumers can avoid problems that can arise from misuse and underestimating their potential dangers. It is imperative to point out that no laser pointer is safe for the eyes.

Based on materials from HealthDay

Remote control for a cat - this is the “nickname” this toy received among its owners. Indeed, a laser pointer for cats is one of the most favorite toys, second only to a fur mouse or a good old bow on a string. A cat chasing a tireless light is absolutely happy. And what somersaults the pet makes when trying to grab ghostly prey!

It is obvious why cats run after the laser - this is an excellent opportunity to satisfy the hunter's instincts: jumping, running, sudden attacks, overcoming obstacles. What cat would refuse such a tempting entertainment? And it’s not difficult to lose excess weight through such catch-ups: all muscle groups are involved, the respiratory and cardiovascular systems are strengthened, and the musculoskeletal system is supported.

In addition, a laser toy for cats is a unique way to overcome stress and relieve tension. Having run actively in the evening, your pet sleeps more soundly at night. With this fun you can even train your cat by learning simple tricks. And it’s convenient for the owner - you can relax in front of the TV while entertaining your pet. And an automatic laser does not require human presence at all: press the button before leaving for work - the cat is entertained for the time allotted by the timer.

However, like any toy, a laser for cats can be dangerous. First of all, you need to remember that the beam should not hit the retina of the eyes, even if reflected from a mirror or glossy surface of furniture. And the more powerful the laser, the faster it destroys the retina. Therefore, a laser pointer must be purchased at a pet store - lasers more powerful than 30 mW cannot be used to play with cats.

There is an opinion that the green color of the beam is safer than the red one. However, only power affects the degree of danger. But if you choose between a red and green laser, it is better to choose green - most cats see the green beam more clearly, even in daylight.

But even a low-power laser pointer for cats can cause injury if handled carelessly. The most “harmless” consequences are shallow wounds and bruises received during the next somersault. Much worse than playing with the windows open is one careless movement of the hand, and the cat jumps out the window, rushing after an elusive light. By the way, children's toys are often equipped with lasers (for example, cars and machine guns), so there should be a mosquito net on the windows, otherwise a child passing by may inadvertently attract a hunter.

And the most unobvious disadvantage is chronic dissatisfaction and self-doubt. A laser toy for cats is hunting in its purest form, which means there must be prey. If every hunt ends in nothing, the cat begins to doubt its ability to get food, and this is inevitable stress. To avoid feelings of dissatisfaction, the cat should receive a “mouse” at the end of the game. You can point the laser at, turning it off when the hunter pokes her nose at the find. Or transfer the beam to another toy that the pet likes to carry in its teeth. If the cat appreciates attention, the laser is moved to the legs and turned off, while stroking and praising the pet that runs up.

Lasers and the radiation from them have been used by humanity for quite some time. In addition to the medical operating environment, such devices are widely used in technical industries. They were adopted by specialists from the field of decoration and special effects creation. Nowadays, 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 be found in everyday life. But not everyone knows how the effect of laser radiation on the human body is reflected during regular and periodic irradiation.

What is laser radiation?

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

In physics terminology, laser radiation refers to 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. A 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 spheres 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 occur not only in the process of direct exposure to the body from the device. Even scattered radiation or reflected rays can cause damage.
• There is a direct connection between the degree of damage and the main parameters of the electromagnetic wave. The location of the irradiated tissue also influences the severity of the lesion.
• The negative effect when energy is absorbed by tissues can be expressed in thermal or light effects.

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

• fever, which is accompanied by a burn;
• boiling of interstitial and cellular fluids;
• the formation of steam creating significant pressure;
• explosion and shock wave, destroying all tissue in the vicinity.

Often, an incorrectly used laser emitter poses, first of all, a threat to the skin. If the influence was particularly strong, the skin will look swollen, with traces of numerous hemorrhages. There will also be large areas of dead cells on the body.

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

The skin, which suffers the most, is the protection of the internal organs of every 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 people with dark skin were less susceptible to deep-seated lesions due to laser irradiation.

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

• I degree. Involves standard epidermal burns.
• 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 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 unofficial ranking of the possible negative effects of laser on the human body are damage to the organs of vision. Short laser pulses can damage the following in a short period of time:

• retina,
• cornea,
• iris,
• lens

There are several reasons for this impact. The main ones are:

• Inability to react 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. Due 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 burned area becomes larger does a person notice the absence of part of the image.

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

• eyelid spasms,
• swelling of the eyelids,
• painful sensations,
• hemorrhage in the retina,
• cloudiness.

Adding to the danger is the fact that retinal cells damaged by the laser 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 urge 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 field of application

Each area of ​​application of laser radiation is oriented towards a strictly defined wavelength.

This indicator directly depends on nature. More precisely, from the electronic structure of the working fluid. This means that the medium in which its radiation is generated 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 working irradiation range can vary from 180 nm to 30 mnm.

The peculiarities of the influence of a laser on the human body are based on the wavelength. For example, a person reacts 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 color almost 30 times more than red.

How to protect yourself from lasers?

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 employees from the possible consequences of radiation. The main rule is the availability of personal protective equipment. Moreover, such means can vary dramatically depending on the predicted degree of danger.

In total, the international classification provides for a division into four hazard classes. The manufacturer must indicate the appropriate marking. Only the first class is considered relatively safe even for the visual organs.

The second class includes direct type radiation that affects the eye organs. Mirror reflection is also included in this category.

Class III radiation is much more dangerous. Its direct exposure threatens the eyes. Reflected diffuse type 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 class, both skin and eyes suffer from various exposure formats.

Collective protective measures at work include:

• special casings,
• protective screens,
• light guides,
• innovative tracking methods,
• alarms,
• blocking.

Relatively primitive but effective methods include fencing the area where irradiation is performed. This will protect workers from accidental exposure due to negligence.

Also, in particularly dangerous enterprises, it is mandatory to use personal protective equipment for employees. They mean a special set of workwear. While working, you cannot do without wearing glasses that provide a protective coating.

Laser gadgets and their radiation

Many people are unaware of how serious the consequences of uncontrolled use of homemade laser-based devices can be. This applies to homemade structures like laser ones:

• lamps,
• pointers,
• flashlights.

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

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

Even if the beam is of low intensity, it can lead to tragedy. If you point the laser at the driver's eyes while actively driving, he may go blind and be unable to control the vehicle.

Under no circumstances should you look into the lens of a laser source. It is also worth considering that glasses for working with lasers 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 always follow them.

Laser radiation is narrowly directed forced energy flows. It can be continuous, of one power, or pulsed, where the power periodically reaches a certain peak. Energy is generated using a quantum generator - a laser. The flow of energy consists of electromagnetic waves that propagate parallel to each other. This creates a minimum light scattering angle and a certain precise directionality.

Scope of application of laser radiation

The properties of laser radiation allow it to be used in various spheres of human activity:

• science - research, experiments, experiments, discoveries;
• military defense industry and space navigation;
• production and technical sphere;
• local heat treatment - welding, cutting, engraving, soldering;
• household use – laser sensors for barcode reading, compact disc readers, pointers;
• laser spraying to increase the wear resistance of metal;
• creation of holograms;
• improvement of optical devices;
• chemical industry - starting and analyzing reactions.

Application of laser in medicine

Laser radiation in medicine is a breakthrough in the treatment of patients requiring surgical intervention. Lasers are used to produce surgical instruments.

The undeniable advantages of surgical treatment with a laser scalpel are obvious. It allows you to make a bloodless soft tissue incision. This is ensured by the instantaneous adhesion of small vessels and capillaries. When using such an instrument, the surgeon fully sees the entire surgical field. The laser energy stream dissects at a certain distance, without contacting the internal organs and vessels.

An important priority is to ensure absolute sterility. The strict direction of the rays allows operations to be performed with minimal trauma. The rehabilitation period for patients is significantly reduced. A person’s ability to work returns faster. A distinctive feature of the use of a laser scalpel is painlessness in the postoperative period.

The development of laser technologies has expanded the possibilities of its application. The properties of laser radiation to positively influence the condition of the skin were discovered. Therefore, it is actively used in cosmetology and dermatology.

Depending on its type, human skin absorbs and reacts to rays differently. Laser radiation devices can create the desired wavelength in each specific case.

Application:

• epilation – destruction of the hair follicle and hair removal;
• acne treatment;
• removal of age spots and birthmarks;
• skin polishing;
• use for bacterial damage to the epidermis (disinfects, kills pathogenic microflora), laser radiation prevents the spread of infection.

Ophthalmology is the first industry to use laser radiation. Directions in the use of lasers in eye microsurgery:

• laser coagulation – the use of thermal properties for the treatment of vascular diseases of the eye (damage to the vessels of the cornea, retina);
• photodestruction – tissue dissection at the peak of laser power (secondary cataract and its dissection);
• photoevaporation - prolonged exposure to heat, used for inflammatory processes of the optic nerve, for conjunctivitis;
• photoablation – gradual removal of tissue, used to treat dystrophic changes in the cornea, eliminates its clouding, surgical treatment of glaucoma;
• laser stimulation - has an anti-inflammatory, absorbable effect, improves trophism of the eye, is used to treat scleritis, exudation in the eye chamber, hemophthalmos.

Laser irradiation is used for skin cancer. The laser is most effective for removing melanoblastoma. Sometimes the method is used to treat stage 1-2 esophageal or rectal cancer. For deep tumors and metastases, the laser is not effective.

What danger does laser pose to humans?

The effect of laser radiation on the human body can be negative. Irradiation can be direct, diffuse and reflected. The negative impact is provided by the light and thermal properties of the rays. The degree of damage depends on several factors - the length of the electromagnetic wave, the location of the impact, the absorption capacity of the tissue.

The eyes are most susceptible to the effects of laser energy. The retina of the eye is very sensitive, so burns often occur. The consequences are partial loss of vision, irreversible blindness. The source of laser radiation is infrared visible light emitters.

Symptoms of laser damage to the iris, retina, cornea, lens:

• pain and spasms in the eye;
• swelling of the eyelids;
• hemorrhages;
• cataract.

Medium-intensity irradiation causes thermal burns to the skin. At the point of contact between the laser and the skin, the temperature rises sharply. Boiling and evaporation of intracellular and interstitial fluid occurs. The skin becomes red. Under pressure, tissue structures rupture. Swelling appears on the skin, and in some cases intradermal hemorrhages. Subsequently, necrotic (dead) areas appear at the burn site. In severe cases, charring of the skin occurs instantly.

A distinctive sign of a laser burn is the clear boundaries of the skin lesion, and blisters form in the epidermis, and not under it.

With diffuse skin lesions at the site of the lesion, it becomes insensitive, and erythema appears after a few days.

Infrared laser radiation can penetrate deep into tissues and affect internal organs. The characteristic of a deep burn is the alternation of healthy and damaged tissue. Initially, when exposed to rays, a person does not experience pain. The most vulnerable organ is the liver.

The impact of radiation on the body as a whole causes functional disorders of the central nervous system and cardiovascular activity.

Signs:

• changes in blood pressure;
• increased sweating;
• unexplained general fatigue;
• irritability.

Precautions and protection against laser radiation

People whose activities involve the use of quantum generators are most at risk of exposure.

In accordance with sanitary standards, laser radiation is divided into four hazard classes. For the human body, the danger is the second, third, fourth classes.

Technical methods of protection against laser radiation:

1. Correct layout of industrial premises, interior decoration must comply with safety regulations (laser beams must not be mirrored).
2. Appropriate placement of radiating installations.
3. Fencing the area of ​​possible exposure.
4. Procedure and compliance with the rules of maintenance and operation of equipment.

Another laser protection is individual. It includes the following equipment: glasses against laser radiation, protective covers and screens, a set of protective clothing (technological gowns and gloves), lenses and prisms that reflect rays. All employees must regularly undergo preventive medical examinations.

Using a laser at home can also be hazardous to health. Improper use of light pointers and laser flashlights can cause irreparable harm to a person. Protection against laser radiation provides simple rules:

1. Do not direct the radiation source at glass or mirrors.
2. It is strictly forbidden to direct the laser into the eyes of yourself or another person.
3. Gadgets with laser radiation must be stored out of the reach of children.

The action of a laser, depending on the modification of the emitter, can be thermal, energetic, photochemical and mechanical. The greatest danger is posed by a laser with direct radiation, with high intensity, narrow and limited beam direction, and high radiation density. Hazardous factors that contribute to exposure to radiation include high operating voltage in the network, air pollution with chemicals, intense noise, and X-ray radiation. Biological effects from laser radiation are divided into primary (local burn) and secondary (nonspecific changes as a response of the whole organism). It should be remembered that the thoughtless use of homemade lasers, light pointers, lamps, laser flashlights can cause irreparable harm to others.