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Laser radiation and its effect on humans. Laser radiation and protection against it in production

LASER RADIATION is the forced (by means of a laser) emission by atoms of matter of portions of quanta of electromagnetic radiation. The word "laser" is an abbreviation formed from initial letters English phrase Light Amplification by Stimulated Emission of Radiation (light amplification using stimulated radiation). Consequently, (an optical quantum generator) is a generator of electromagnetic radiation in the optical range, based on the use of stimulated radiation. A laser installation includes an active (laser) medium with an optical resonator, a source of its excitation energy and, as a rule, a cooling system. Due to the monochromatic nature of the laser beam and its low divergence ( high degree collimation) exceptionally high energy exposures are created, allowing one to obtain a local thermal effect. This is the basis for the use of laser systems in materials processing (cutting, drilling, surface hardening, etc.), in surgery, etc.

L. and. is capable of propagating over considerable distances and being reflected from the interface between two media, which makes it possible to use this property for the purposes of location, navigation, communication, etc. By selecting certain substances as an active medium, it can induce at almost all wavelengths, starting from ultraviolet and ending with long-wave infrared. The most widely used in industry are lasers that generate electromagnetic radiation with a wavelength of 0.33; 0.49; 0.63; 0.69; 1.06; 10.6 microns.

The main physical quantities characterizing lasers:

wavelength, µm;

use of protective equipment;

limiting the time of exposure to radiation;

appointment of persons responsible for organizing and carrying out work;

restriction of access to work;

Supervision of work schedule;

clear emergency response and regulation of the procedure for conducting work in emergency conditions;

Personnel.

Sanitary-hygienic and treatment-and-prophylactic methods:

control over the levels of harmful and dangerous factors in the workplace;

control over the passage of preliminary and periodic medical examinations by personnel.

From L. and. must ensure the prevention of exposure to radiation or its reduction to a level not exceeding the permissible level. To SKZ from L. and. include: fencing, protective screens, locks and automatic shutters, casings, etc. PPE from L. and. include: shields, masks, etc. VS should be provided at the stage of design and installation of lasers, when organizing workplaces, and when choosing operational parameters. The choice of protective equipment should be made depending on the class of the laser, the intensity of radiation in the work area, and the nature of the work performed. Indicators protective properties protective equipment should not be reduced under the influence of other harmful and dangerous factors (vibration, temperature, etc.). The design of protective equipment must provide the ability to change the main elements (light filters, screens, sight glasses, etc.). PPE for the eyes and face (and shields), which reduces the intensity of L. and. to PDU, should be used only in those cases (commissioning, repair and experimental work) when VCS does not provide personnel.

Laser radiation is electromagnetic radiation generated in the wavelength range l = 180...105 nm. Laser systems have become widespread.

Laser radiation is characterized by monochromaticity (radiation of almost the same frequency), high coherence (preservation of the oscillation phase), extremely low energy divergence of the beam and high concentration radiation energy in the beam.

Biological effects The effects of laser radiation on the body are determined by the mechanisms of interaction of radiation with tissues and depend on the radiation wavelength, pulse duration (exposure), pulse repetition rate, area of the irradiated area, as well as on the biological and physico-chemical characteristics of the irradiated tissues and organs. There are thermal, energetic, photochemical and mechanical (shock-acoustic) effects, as well as direct and reflected (mirror and diffuse) radiation. For eyes, skin and internal tissues of the body great danger represents energy-saturated direct and specularly reflected radiation. In addition, there are negative functional changes in the functioning of the nervous and cardiovascular systems, endocrine glands, changes blood pressure, fatigue increases.

Laser radiation with a wavelength from 380 to 1400 nm is most dangerous for retina eyes, and radiation with a wavelength from 180 to 380 nm and over 1400 nm - for the anterior media of the eye. Skin damage can be caused by radiation of any wavelength in the considered range (180...105 nm).

The tissues of a living organism at low and medium irradiation intensities are almost impenetrable to laser radiation. Therefore, the surface (skin) integuments are most susceptible to its effects. The degree of this effect is determined by the wavelength and intensity of the radiation.

At high intensities laser irradiation Damage not only to the skin, but also to internal tissues and organs is possible. These injuries are characterized by edema, hemorrhage, tissue necrosis, as well as coagulation or breakdown of blood. In such cases, skin damage is relatively less pronounced than changes in internal tissues, and no pathological changes were noted in the adipose tissues at all.

Biological effects that occur when exposed to laser radiation on the body are conventionally divided into groups:

a) primary effects - organic changes, arising directly in irradiated living tissues (direct irradiation);

b) secondary effects - nonspecific changes, arising in the body in response to radiation (long-term exposure to diffusely reflected radiation).

When operating laser systems, a person may be exposed to the following dangerous and harmful factors, caused both by the laser radiation itself and the specifics of its formation:

laser radiation (direct, reflected, scattered);
ultraviolet, visible and infrared radiation structural components;
high voltage in control and power supply circuits;
EMF of industrial frequency and radio frequency range;
x-ray radiation from gas discharge tubes and elements operating at anode voltage more than 5 kV;
noise and vibration;
toxic gases and vapors formed in laser elements and during the interaction of the beam with the environment;
products of interaction of laser radiation with processed materials;
elevated temperature surfaces of the laser product and in the irradiation zone;
danger of explosion in laser pumping systems;
the possibility of explosion and fire when the beam interacts with flammable material.

According to the degree of radiation danger for biological structures Human lasers are divided into four classes.

To lasers 1st class are completely safe lasers. Their radiation does not pose a danger to the eyes and skin.

Lasers 2 classes- These are lasers, the beam of which poses a danger when irradiating human skin or eyes. However, diffusely reflected radiation is safe for both skin and eyes.

Lasers 3 classes pose a danger when irradiating the eyes and skin with direct, specularly reflected radiation. Diffusely reflected radiation is dangerous for the eyes at a distance of 10 cm from the diffusely reflective surface, but is safe for the skin.

At lasers 4 classes Diffusely reflected radiation at a distance of 10 cm from a diffusely reflective surface poses a danger to the eyes and skin.

Lasers are classified by the manufacturer according to their output radiation characteristics.

When operating installations of classes 2-4, laser safety measures, dosimetric monitoring of laser radiation, sanitary and hygienic measures and medical control should be provided.

Laser safety- this is a set of technical, sanitary-hygienic, treatment-and-prophylactic and organizational measures that ensure safe and harmless working conditions when operating laser systems.

Laser radiation is regulated according to maximum permissible irradiation levels (MALs) in accordance with “Sanitary standards and rules for the design and operation of lasers” No. 5804-91 . Maximum radiation levels with a single exposure can lead to an insignificant probability of reversible abnormalities in the worker’s body. Maximum radiation levels during chronic exposure do not lead to deviations in the state of human health both during work and in the long-term life of the present and subsequent generations.

The normalized parameters are irradiance E, energy exposure H, energy W and radiation power P.

Irradiance is the ratio of the radiation flux incident on a small surface area to the area of this area, W/m2.

Energy exposition determined by the irradiance integral over time, J/m2.

Laser radiation remote control units are set for three wavelength ranges (180...380, 381...1400, 1401...105 nm) and cases of irradiation: single (with exposure time up to one shift), series of pulses and chronic (systematically repeated). In addition, when standardizing, the object of irradiation is taken into account (eyes, skin, eyes and skin at the same time).

When using lasers in theatrical and entertainment events, for demonstration in educational institutions, for illumination and other purposes in medical devices, not directly related to therapeutic effect radiation, MRLs for all exposed persons are set in accordance with the standards for chronic exposure.

Depending on their hazard classes, laser products are subject to different requirements. For example, lasers of classes 3 and 4 must contain dosimetric equipment, and their design must

enable remote control. Laser products medical purposes must be equipped with a means to measure the level of radiation exposed to patients and personnel. Lasers of classes 3 and 4 are prohibited from being used in theatrical and entertainment events, in educational institutions and in open spaces. The class of the laser product is taken into account in the requirements for its operation.

Laser products and laser radiation propagation zones must be marked with laser hazard signs with explanatory notes depending on the class of the laser.

Safety when working with open laser products is ensured by using PPE. Safety when using lasers for demonstration purposes, in theatrical and entertainment events and at open space is ensured by organizational and technical measures (development of a laser placement scheme, taking into account the trajectory of laser beams, strict control for compliance with rules, etc.).

When using glasses to protect against laser radiation, the illumination levels of workplaces must be increased by one level in accordance with SNiP 23-05-95.

Protective equipment (collective and individual) is used to reduce the levels of laser radiation affecting humans to values below the maximum permissible level. The choice of protective equipment is carried out taking into account the parameters of laser radiation and operating features. PPE against laser radiation includes eye and face protection ( safety glasses, selected taking into account the wavelength of radiation, shields, attachments), hand protection, special clothing.

Personnel working with laser products must undergo preliminary and periodic (once a year) medical examinations. Persons over 18 years of age and without medical contraindications are allowed to work with lasers.

Lasers are becoming increasingly important research tools in medicine, physics, chemistry, geology, biology and engineering. At misuse they can cause blinding and injury (including burns and electrical shock) to operators and other personnel, including bystanders, as well as significant property damage. Users of these devices must to the fullest understand and apply necessary measures safety when handling them.

What is a laser?

The word “laser” (LASER, Light Amplification by Stimulated Emission of Radiation) is an abbreviation that stands for “light amplification by stimulated emission of radiation.” The frequency of the radiation generated by the laser is within or near the visible part electromagnetic spectrum. The energy intensifies to a state of extreme high intensity using a process called laser-induced emission.

The term radiation is often misunderstood because it is also used to describe In this context, it means the transfer of energy. Energy is transferred from one place to another through conduction, convection and radiation.

There are many various types lasers operating in different environments. The working medium used is gases (for example, argon or a mixture of helium and neon), solid crystals (for example, ruby) or liquid dyes. When energy is supplied to the working medium, it becomes excited and releases energy in the form of particles of light (photons).

A pair of mirrors at either end of a sealed tube either reflects or transmits light in a concentrated stream called a laser beam. Each operating environment produces a beam of unique wavelength and color.

The color of laser light is typically expressed by wavelength. It is non-ionizing and includes ultraviolet (100-400 nm), visible (400-700 nm) and infrared (700 nm - 1 mm) parts of the spectrum.

Electromagnetic spectrum

Each electromagnetic wave has a unique frequency and length associated with this parameter. Just as red light has its own frequency and wavelength, all other colors - orange, yellow, green and blue - have unique frequencies and wavelengths. Humans are able to perceive these electromagnetic waves, but are unable to see the rest of the spectrum.

Ultraviolet radiation also has the highest frequency. Infrared, microwave radiation and radio waves occupy the lower frequencies of the spectrum. Visible light lies in a very narrow range between the two.

impact on humans

The laser produces an intense, directed beam of light. If directed, reflected, or focused onto an object, the beam will be partially absorbed, raising the temperature of the surface and interior of the object, which can cause the material to change or deform. These qualities, which are used in laser surgery and materials processing, can be dangerous to human tissue.

In addition to radiation that has a thermal effect on tissue, laser radiation that produces a photochemical effect is dangerous. Its condition is a sufficiently short, i.e., ultraviolet or blue part of the spectrum. Modern devices produce laser radiation, the impact of which on humans is minimized. Low-power lasers do not have enough energy to cause harm, and they do not pose a danger.

Human tissue is sensitive to energy, and under certain circumstances, electromagnetic radiation, including laser radiation, can cause damage to the eyes and skin. Studies have been conducted on threshold levels of traumatic radiation.

Eye hazard

The human eye is more susceptible to injury than the skin. The cornea (the clear outer front surface of the eye), unlike the dermis, does not have an outer layer of dead cells to protect it from environmental influences. The laser is absorbed by the cornea of the eye, which can cause harm to it. The injury is accompanied by swelling of the epithelium and erosion, and in case of severe injuries - clouding of the anterior chamber.

The lens of the eye can also be susceptible to injury when it is exposed to various laser radiation - infrared and ultraviolet.

The greatest danger, however, is the impact of the laser on the retina in the visible part of the optical spectrum - from 400 nm (violet) to 1400 nm (near infrared). Within this region of the spectrum, collimated beams are focused onto very small areas of the retina. The most unfavorable impact occurs when the eye looks into the distance and is hit by a direct or reflected beam. In this case, its concentration on the retina reaches 100,000 times.

Thus, a visible beam with a power of 10 mW/cm 2 affects the retina with a power of 1000 W/cm 2. This is more than enough to cause damage. If the eye does not look into the distance, or if the beam is reflected from a diffuse, non-mirror surface, significantly more powerful radiation leads to injury. Laser exposure to the skin does not have a focusing effect, so it is much less susceptible to injury at these wavelengths.

X-rays

Some high voltage systems with voltages greater than 15 kV can generate x-rays significant power: laser radiation, the sources of which are powerful with electronic pumping, as well as plasma systems and ion sources. These devices must be tested to ensure proper shielding, among other things.

Classification

Depending on the power or energy of the beam and the wavelength of the radiation, lasers are divided into several classes. The classification is based on the device's potential to cause immediate injury to the eyes, skin, or fire when directly exposed to the beam or when reflected from diffuse reflective surfaces. All commercial lasers must be identified by markings applied to them. If the device was home-made or otherwise not marked, advice should be obtained regarding its appropriate classification and labeling. Lasers are distinguished by power, wavelength and exposure duration.

Secure Devices

First class devices generate low-intensity laser radiation. It can't reach dangerous level, so sources are exempt from most controls or other forms of surveillance. Example: laser printers and CD players.

Conditionally safe devices

Second class lasers emit in the visible part of the spectrum. This is laser radiation, the sources of which cause in humans a normal reaction of aversion to too bright light ( blink reflex). When exposed to beam human eye blinks after 0.25 s, which provides sufficient protection. However, laser radiation in the visible range can damage the eye with constant exposure. Examples: laser pointers, geodetic lasers.

Class 2a lasers are special-purpose devices with an output power of less than 1 mW. These devices only cause damage when directly exposed for more than 1000 seconds in an 8-hour work day. Example: barcode readers.

Dangerous lasers

Class 3a includes devices that do not cause injury during short-term exposure to an unprotected eye. May pose a hazard when using focusing optics such as telescopes, microscopes or binoculars. Examples: 1-5 mW helium-neon laser, some laser pointers and building levels.

A Class 3b laser beam can cause injury through direct exposure or specular reflection. Example: Helium-neon laser 5-500 mW, many research and therapeutic lasers.

Class 4 includes devices with power levels greater than 500 mW. They are dangerous to the eyes, skin, and are also a fire hazard. Exposure to the beam, its specular or diffuse reflections can cause eye and skin injuries. All safety measures must be taken. Example: Nd:YAG lasers, displays, surgery, metal cutting.

Laser radiation: protection

Each laboratory must provide adequate protection for persons working with lasers. Room windows through which radiation from a Class 2, 3, or 4 device may pass through causing harm in uncontrolled areas must be covered or otherwise protected while such device is operating. To ensure maximum eye protection, the following is recommended.

The beam must be enclosed in a non-reflective, non-flammable containment to minimize the risk of accidental exposure or fire. To align the beam, use fluorescent screens or secondary sights; Avoid direct contact with eyes.
Use the lowest power for the beam alignment procedure. If possible, use low-class devices for preliminary alignment procedures. Avoid the presence of unnecessary reflective objects in the laser operating area.
Limit the passage of the beam into the danger zone during non-working hours using shutters and other barriers. Do not use room walls to align the beam of Class 3b and 4 lasers.
Use non-reflective tools. Some inventory not reflecting visible light, becomes specular in the invisible region of the spectrum.
Do not wear reflective jewelry. Metal jewelry also increases the risk of electric shock.

Safety glasses

Safety glasses should be worn when working with Class 4 lasers with an open hazardous area or where there is a risk of reflection. Their type depends on the type of radiation. Glasses should be selected to protect against reflections, especially diffuse reflections, and to provide protection to a level where the natural protective reflex can prevent eye injury. Such optical instruments will maintain some visibility of the beam, prevent skin burns, and reduce the possibility of other accidents.

Factors to consider when choosing safety glasses:

wavelength or region of the radiation spectrum;
optical density at a certain wavelength;
maximum illumination (W/cm2) or beam power (W);
type of laser system;
power mode - pulsed laser radiation or continuous mode;
reflection possibilities - specular and diffuse;
field of view;
the presence of corrective lenses or sufficient size to allow the wearing of glasses for vision correction;
comfort;
the presence of ventilation holes to prevent fogging;
influence on color vision;
impact resistance;
ability to perform necessary tasks.

Because safety glasses are susceptible to damage and wear, the laboratory safety program should include periodic inspection of these safety features.

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 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, 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.

Undeniable advantages surgical treatment laser scalpel are obvious. It allows you to make a bloodless soft tissue incision. This is ensured by instant soldering 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.

Development laser technologies allowed to expand 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 desired length waves 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 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 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.

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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.

When exposed to medium intensity irradiation, thermal burns 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.

Laser radiation infrared spectrum can penetrate deep into tissues and affect internal organs. The characteristic feature 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 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.

According to 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, and high radiation density. Hazardous factors that contribute to exposure include high production voltage in the network, air pollution chemicals, intense noise, x-ray radiation. Biological effects from laser radiation are divided into primary (local burn) and secondary (nonspecific changes such as response 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.

IN last decades in industry, medicine, scientific research, lasers have been used in environmental monitoring systems. Their radiation can have dangerous influence on the human body and primarily on the organ of vision. Laser radiation (LR) is generated in the infrared, light and ultraviolet regions of non-ionizing EMR.

Lasers generating continuous radiation make it possible to create an intensity of the order of 10 10 W/cm 2, which is sufficient to melt and evaporate any material. When generating short pulses, the radiation intensity reaches values of the order of 10 15 W/cm 2 and more. For comparison, note that the intensity value sunlight close earth's surface is only 0.1 – 0.2 W/cm 2 .

Currently, a limited number of laser types are used in industry. These are mainly lasers that generate radiation in the visible range of the spectrum (λ = 0.44‒0.59 µm; λ = 0.63 µm; λ = 0.69 µm), near-infrared range of the spectrum (λ = 1.06 µm) and far-IR spectral range (λ = 10.6 µm). When assessing adverse influence All hazards of lasers are divided into primary and secondary. The first include factors whose source of formation is directly laser machine. Secondary factors arise as a result of the interaction of the LI with the target.

Primary hazard factors include radiation exposure, increased electrical voltage, light radiation, acoustic noise and vibration from the operation of auxiliary equipment, air pollution by gases released from installation components, X-ray radiation from electroionization lasers or electric vacuum devices operating at voltages above 15 kV.

Secondary factors include reflected radiation, aerodispersed systems and acoustic noise generated during the interaction of laser radiation with a target, and plasma plume radiation.

LI can pose a danger to humans, causing in his body pathological changes, functional disorders of the organ of vision, central nervous and autonomic systems, and also affect internal organs such as the liver, spinal cord etc. LI poses the greatest danger to the organ of vision. The main pathophysiological effect of tissue irradiation with LI is a superficial burn, the degree of which is related to the spatial-energetic and temporal characteristics of the radiation.

Impact of laser radiation on the eyes. Relatively easy vulnerability of the cornea and lens of the eye when exposed to electromagnetic radiation a wide range of wavelengths, as well as the ability optical system eyes increase the energy density of visible and near-infrared radiation in the fundus by several orders of magnitude relative to the cornea, making it the most vulnerable organ. The degree of eye damage mainly depends on physical parameters such as exposure time, energy flux density, wavelength and type of radiation (pulsed or continuous), as well as individual characteristics eyes.

Impact ultraviolet radiation on the organ of vision mainly leads to damage to the cornea. Superficial burns of the cornea by laser radiation with a wavelength within the ultraviolet region of the spectrum are eliminated during the process of self-healing.

For laser radiation with a wavelength of 0.4 – 1.4 μm, the critical element of the organ of vision is the retina. It is highly sensitive to electromagnetic waves in the visible region of the spectrum and is characterized by a high absorption coefficient of electromagnetic waves in the visible infrared and near ultraviolet regions. Damage to the eye can range from mild retinal burns with little or no changes visual function, up to serious damage, leading to vision deterioration and even complete loss.

Radiation with wavelengths greater than 1.4 µm is almost completely absorbed in vitreous body and aqueous humor of the anterior chamber of the eye. With moderate damage, these eye environments are capable of self-healing. Mid-infrared laser radiation can cause severe thermal damage to the cornea.

Note that laser radiation has a damaging effect on all structures of the organ of vision. The main mechanism of damage is thermal effect. Pulsed laser radiation is more dangerous than continuous laser radiation.

The effect of laser radiation on the skin. Skin damage caused by laser radiation can range from mild redness to superficial charring and deep skin blemishes. Effect on skin determined by laser radiation parameters and the degree of skin pigmentation.

Threshold levels of radiation energy at which visible changes occur on the skin vary over a relatively wide range

(from 15 to 50 J/cm2).

The biological effects that occur when skin is irradiated with laser radiation, depending on the wavelength, are given in Table. 5.

Table 5

Biological effects that occur when skin is irradiated with laser radiation