Positive and negative effects of laser radiation on the human body. Laser hair removal: contraindications and consequences

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

Properties laser radiation allows it to be used in various fields human life:

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, CD 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.

Undeniable advantages surgical treatment 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. Rehabilitation period patients is significantly reduced. A person’s ability to work returns faster. Distinctive feature The use of a laser scalpel is painless 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 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 treatment vascular diseases eyes (damage to blood 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 optic nerve, with conjunctivitis;
photoablation – gradual removal of tissue, used for treatment dystrophic changes cornea, eliminates its cloudiness, surgical treatment 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 oncological diseases skin. 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.

Stories from our readers

Vladimir
61 years old

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. Negative Impact provided by the light and thermal properties of 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 tissue and damage 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 effect of radiation on the body as a whole causes functional disorders of the central nervous system, 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:

Correct layout of industrial premises, interior decoration must comply with safety regulations (laser beams should not be mirrored).
Appropriate placement of radiating installations.
Fencing the area of possible exposure.
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:

Do not direct the radiation source at glass or mirrors.
It is strictly forbidden to direct the laser into the eyes of yourself or another person.
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, high density radiation. TO hazardous factors factors that contribute to exposure include high production voltage, air pollution chemicals, intense noise, 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.

Doctors do not recommend shining a laser pointer into your eyes, as long-term exposure can cause retinal damage. If discomfort occurs in the visual area, you should consult an ophthalmologist. An acute reaction of the body may indicate the occurrence of serious pathological processes in the body and ophthalmological diseases.

Why can't you shine a laser into your eyes?

In everyday life and educational institutions Most often, laser pointers with a power of no more than 5 mW are used, which do not pose a high danger to the visual organs.

The most common are red electronic devices that emit electromagnetic waves in the visible spectrum. Bright light provokes a sharp contraction of the pupils, which is fraught with the temporary appearance of black dots in the field of view and blurred visual image. Long-term exposure to lasers with power exceeding 20 mW causes thermal burn retina, which can cause irreversible pathological processes in the eyes and damage the retina. The most powerful pointers used in industry have green light and power - 1-2 W. Working with such equipment without protective equipment is prohibited, as it is very dangerous for the eyes. However, in Everyday life It is unlikely to encounter lasers of such power.

Consequences of glow in the eyes

If a person’s visual organs are sensitive, their reaction to such exposure may be lacrimation.

Conventional laser pointers do not harm the eyes, unlike industrial ones, which can cause burns and loss of vision. However, with prolonged exposure and increased photosensitivity, the following unpleasant symptoms may occur.

Sep 17

What happens if a laser beam hits the eye? Or a few words about safety when performing laser procedures in cosmetology

It was 50 years ago that laser was used only to remove tumors, and then only on the face and body. Since the advent of devices with finer settings, anti-aging and tattoo removal procedures began to affect the areas of the eyebrows, the outer corners of the eye, and the ciliary edges of the eyelid. But the eye is not far away! Is it dangerous or not? What happens if the laser does get into the eye? How to eliminate risks for the patient and the doctor?

Lasers are different

Medical laser systems have 4 hazard classes:

Class 1 considered incapable of generating damaging levels of radiation during operation. It is safe under all conditions of normal use with the naked eye or magnifying optics. These systems are exempt from any controls or other types of surveillance. An example is lasers used in diagnostic laboratories. Class 1M is considered unable to produce hazardous conditions exposure during normal operation, if the beam is not viewed using magnifying optics.
Class 2– low power laser systems; they emit light in the visible part of the spectrum (400-700 nm) and are considered safe because the defense mechanisms (our blink reflex) provide protection. An example is the helium-neon laser (laser pointers).
Class 2M - emits light in the visible part of the spectrum. Eye protection is normally provided by involuntary closing of the eyes when looking at them. However, these systems are potentially dangerous when viewed with some optical devices.
Medium Power Laser Systems class 3. They can be dangerous when viewed directly or when looking at a specular reflection of the beam. They are not sources of diffuse reflection and are not a fire hazard. An example of a Class 3 laser is the Nd:YAG laser used in ophthalmology.
There are 2 subclasses: 3R and 3B. Class 3R. May be dangerous under some direct and specular reflection conditions if the eye is properly focused and stable and there is little chance of actual damage. Class 3B. May be hazardous in direct and specular conditions.
Class 4. These are high power systems. They are the most dangerous; they can be sources of diffuse reflection and are a fire hazard. They can also produce dangerous plasma radiation. These are cosmetic lasers: carbon dioxide, neodymium, argon, alexandrite, pulsed dye laser (PDL).

Laser operating principle

Laser radiation wavelengths fall in the ultraviolet, visible and infrared ranges of the electromagnetic spectrum.

Almost all cosmetic lasers operate on the principle of selective photothermolysis. This means that their laser energy is absorbed by a specific chromophore:

melanin – for diode, alexandrite and ruby lasers and dye lasers (PDL);
hemoglobin – for neodymium in yttrium-aluminum garnet and PDL;
water – for erbium and carbon dioxide lasers, while preserving the surrounding tissue.

For the laser to provide required action, three basic requirements must be met:

Wavelength sufficient for a certain penetration depth.
An exposure duration (laser pulse width and duration) less than or equal to the thermal relaxation time (TRT) of the target.
Sufficient energy per unit area (fluence) to cause irreversible damage to the target chromophore.

The power, spot size and duration of the laser are also important. Thus, with a larger spot size, less scattering occurs, but deeper tissue penetration occurs.

Although lasers target specific chromophores, the surrounding scatter and the resulting thermal effect can cause side effects. Thermal damage occurs when sufficient energy is absorbed by a suitable chromophore with more high speed than the resulting heat can be dissipated. While core tissue chromophores are targeted, other ocular structures that are also rich in these chromophores are susceptible to unintentional damage. They can be the retina, rich in hemoglobin and melanin, the choroid, rich in melanin, the cornea and lens, which contain a lot of fluid.

Features of the eyelid and eye

When conducting laser procedures In the area surrounding the eye, you need to remember the following:

The skin of the eyelids is very thin.
The eye contains several targets for different laser beams. This is melanin in the retinal epithelium, the pigment of the iris, as well as water, which makes up most eyeball.
The most vulnerable part of the eye is the retina: a laser beam 400-1400 nm long (and especially 700-1400 nm) is focused directly on it using the convexities of the lens and cornea. As a result, the retina receives 105 times more radiation than the cornea.
There is such a thing as the Bell phenomenon: when the eye is closed, eyeball naturally rolls up. In this way, the pigmented iris can enter the laser penetration range and absorb the radiation.
On the cornea pain receptors located very tightly. That is, even minor thermal damage leads to severe pain.

Light-eyed patients are especially susceptible to laser injury if the laser is used to target melanin. In them, all the radiation hits the retina immediately, without decreasing when passing through the epithelium of the iris.

How laser damages eye structures

Laser eye injury and the possible extent of damage varies and depends on the type of laser. Thus, devices operating on the basis of potassium titanyl phosphate (KTP) or dyes (PDL) have short length. They are mainly absorbed by the cornea and lead to photocoagulation, that is, a photothermal effect. In this case, it is generated in the eye tissue sufficient quantity heat to denature proteins. The retinal temperature can increase from 40 to 60° C.

Lasers emitting long wavelengths - infrared, diode, Nd: YAG. They pass through the cornea to reach the lens and retina. Their effect is photomechanical, less often the phenomenon of photocoagulation. The photomechanical effect implies that an explosive acoustic shock is generated in the tissues, which can lead to the appearance of fragments and even perforation of individual structures.

For example, clinically the 1064 nm Nd:YAG laser, which causes most laser eye injuries, is capable of causing retinal hemorrhage, in vitreous, as well as scarring, preretinal adhesions, and retinopathy when radiation is absorbed by the melanin-rich retinal pigment epithelium. The Nd:YAG laser can cause significant damage to the eye and surrounding skin compared to shorter wavelength lasers because it can penetrate deeper layers of the skin.

The danger with long wavelength lasers (e.g. 755-795 nm alexandrite and 1064 nm Nd:YAG laser) is that their beam is invisible to the eye. This distinguishes them from shorter wavelength (eg KTP) lasers.

Erbium: The 2940 nm YAG laser is another ablative laser that can also be used fractionally. It is more efficiently absorbed by water and collagen and causes less thermal damage than CO2 laser. Complications of these lasers include erythema, hyper- and hypopigmentation of the iris, skin infections and corneal injury.

How does the eye work?
Welding

Laser devices and pointers: dangerous entertainment for children “Don’t look at the welding, you’ll go blind!” Each of us has heard this phrase from our parents at least once, and probably told it to our children. “You can’t shine a laser pointer into your eyes!”, “You can’t enter a room with a quartz lamp on!” - Same. MedAboutMe will try to figure out how justified these statements are.

How does the eye work?

The eyes of humans, and other mammals and birds too, are a wonderful biological device, optical device, allowing us to see.

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

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

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

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

The retina contains several layers of nerve cells special type, which, in fact, provide the eye’s ability to see. In these cells, light is converted into an electrical impulse transmitted optic nerve to the brain, which recognizes and interprets the signals it receives. Optic cells There are two types: “rods” and “cones”. Their main part is located in the central part of the retina, in the macula.

The eye's ability to see depends on the work of everyone components, all its departments. Violation of the functions of any of the departments leads to deterioration or loss of vision. This condition can be temporary or permanent, irreversible.

Eye injuries from laser, welding, quartz lamp

The dangers posed by a quartz lamp, welding and laser emitters are not the same. A quartz lamp is a source of ultraviolet radiation, under the influence of which a burn of eye tissue develops. 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 eye's ability to see. Severe burns leave behind irreversible 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 mild corneal burns to retinal damage.

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

Otherwise, the laser beam works. Possessing great penetrating power and high energy density in cross section beam, the laser penetrates into the deep structures of the eye and destroys sensitive nerve cells retina, and irrevocably. There is no pain 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 membranes of the eye. Others even penetrate optically opaque materials that are impervious to infrared and ultraviolet radiation.

There is a classification of lasers according to the degree of danger, from the first, 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. Lasers of the fourth hazard class can even ignite flammable materials, while devices belonging to classes 1 and 2 are dangerous only in certain, unlikely conditions. Hazard class 2 includes, in particular, laser scanners cash registers and recognition devices.

How to determine the danger level of a laser

As already mentioned, class 1 and 2 lasers are practically safe. The first class includes, for example, the family of laser mice. Their power is so low that they do not pose a danger. Laser barcode scanners belong to class 2. The beam from them can only be seen under certain conditions. The radiation source can cause damage to the organs of vision only if the beam continuously impacts the retina from a minimum distance for at least 30 seconds. Class 2a lasers are installed and secured in such a way that accidental exposure of the beam to the eyes 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 harm. A class 3b radiation source is certainly dangerous; you can’t even close your eyes; it even burns your skin. Such sources are installed in CD-ROMs and 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 or smoke from the side, as well as all powerful laser pointers and, in general, all sources more powerful than 5 mW. Such lasers, unfortunately, are often used in clubs and discos to create visual effects. At the same time, they are often directed directly at the crowd.

All cutting lasers belong to the very dangerous fourth class.

Fact! In the summer of 2008, about 30 people who participated in the Aquamarine festival lost their sight. They suffered serious and irreversible retinal injuries caused by lasers used during the show.

Lasers have been used in the entertainment industry for many years, and this equipment is quite affordable. Sometimes it is purchased by people who have no idea about safety regulations.

There have been cases of vision loss as a result of laser burns in other cities, although not as widespread.

Protecting the eyes of a child or teenager from burns with a quartz lamp

A home quartz lamp is one of the devices whose benefits are ambiguous when used in everyday life. 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 in a room if there are people or animals in it. If a child is irradiated by medical indications, then the procedure should take place wearing safety glasses with high UV protection.
The switch must be located so that the child cannot, under any circumstances, be able to turn on the lamp himself.

Accidental eye burns are unpleasant and painful, but disappear within a few days. Severe injuries can lead to damage to the deep structures of the organ of vision and blindness. Cataracts are likely to develop.

Welding

Electric welding creates radiation that is dangerous to the eyes. Professional welders are well aware of what an “eye burn” is. They call this condition "caught bunnies." This sometimes happens even to experienced welders, and even more often when safety precautions are violated by distracted or inexperienced workers. In medicine there is even special term for an eye burn from electric welding: electrophotoophthalmia.

Light burn or medium degree very unpleasant, but usually goes away in a few days. The conjunctiva may turn red and swell, lacrimation may increase, and the cornea may become cloudy.

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

Harmful bacteria can enter the affected tissue. If treatment is not started on time, the likelihood of an unfavorable course of the disease will increase sharply, including complete and permanent 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, but the bright spark and crackling sound of the welding machine will certainly attract the child’s attention. Parents should early childhood explain why you should not look at welding with unprotected eyes. If this does happen, it is necessary to immediately take the child to emergency eye care. Timely treatment will most likely relieve not only the consequences of the injury, but also its painful and very unpleasant symptoms.

Important! If you receive a welding burn, you should not allow your child to rub his eyes, as this will only worsen his condition and increase pain and inflammation.

Cannot also be used eye drops unless prescribed by a doctor. Some of these drugs contain substances that can cause irritation to the mucous membranes. In case of a burn, they can worsen the condition of the injured eye.

Laser devices and pointers: dangerous entertainment for children

As a rule, ordinary laser pointers sold in kiosks and stores fall into the hands of children. They are most often made in China. You cannot trust what is written on the product body or its packaging. Practice shows that real characteristics can differ greatly from those stated, both up and down.

Even low-power laser radiation sources are dangerous for a child’s eyes. And some particularly inventive teenagers manage to install much more powerful radiation sources into the body of an ordinary low-power pointer, which they “extract” from an old printer, for example.

If a child has a laser pointer of any power, it is necessary to explain safety precautions to him and make sure that the child understands everything. And even after that, do not leave him alone with a pointer, without adult supervision.

Never use a powerful pointer on the street.
When playing home laser entertainment for children, you need to make sure that the beam does not fly out the window.
It is strictly forbidden to direct the beam at the windows of houses, balconies, the faces of passers-by, or animals. Laser ray, aimed at a flying aircraft, may give rise to a criminal case with very serious liability.
Remember that neither ordinary Sunglasses, not even welding masks will protect your eyes from the laser. But the beam can be reflected from them and end up somewhere unknown.
Make sure that there is a push-button switch on the pointer, which must be kept pressed constantly.
Relatively powerful laser beams can be dangerous even when reflected. The beam can be reflected from any glass or polished surface: from the floor, furniture walls, table surface, etc. Therefore, it is dangerous to play with a laser pointer with pets. In the heat of the game, you may not notice that the beam was reflected from the laminate on the floor or the mirror in the hallway, and the reflection got into the eyes of your pet or, even worse, the child himself holding a pointer.
If a child complains of blurred vision, it is necessary to visit an ophthalmologist as quickly as possible.

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? Yes and excess weight It’s not difficult to lose 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 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 green color ray is safer than red. 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 scarier than the game open windows– one careless movement of the hand, and the cat jumps out the window, rushing after the 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. Laser toy for cats is a hunt in pure form, which means there must be production. 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.