On the basis of our own model experiments and extensive literary data, we discuss in the present paper the role of various parameters of laser irradiance ((lambda) , p, t) and spectral features of the exposed target in various transformations occurring within the latter. Delivery of effective energy to the required depth is basically achieved by the selection of an irradiance, adequate in wavelength and, therefore, penetrating capacity for ocular tissues. Both regulation of the density of irradiance intensity per unit volume of the exposed tissue and geometry of the beam, also selection of beam color, in relation to the target spectral composition, provide for the quantitative aspect of exposure. As concerns qualitative features of the prevailing response (thermal, mechanical, ablation) these are largely determined by appropriate selection of pulses of required duration and frequency. Other parameters also play a significant role, especially in attaining ablation effect.

Antiviral, antibacterial, antitumoral effects of laser coagulation are now of great importance in clinical ophthalmology for different corneal diseases treatment. One can note, that nowadays solid-state free-mode pulsed near-and-mid-infrared lasers with the 1.3 - 3.0 micrometers wavelengths may become widespreadly accepted in this field of ophthalmosurgery. The corneal tissue absorption coefficients for these wavelengths are lying from some parts to several thousand cm^-1. Thus, by proper selection of laser wavelength, possibility is appeared to coagulate precisely the seat of pathological alterations without damaging of more deeper, non changed corneal tissue. In our work the comparative experimental study results of rabbit cornea coagulation after exposure with using of different IR lasers (with 1.32; 1.54; 1.96; 2.09 and 2.84 micrometers wavelengths) are presented. Pulse duration was about 10^-3 s. The subthreshold, threshold and superthreshold energy levels were studied. Threshold energies were registered if slightly noticed coagulative changes appeared in exposed volume of corneal tissue. The cornea response resulting from laser radiation exposure was evaluated by clinical examination, slit lamp biomicroscopy, light microscopy, fluorescent staining and biochemistry. For all wavelengths initial damage was found within the cornea layers. Superthreshold injury revealed the same picture except that for 1.32 micrometers the threefold increase of the threshold energy caused additionally iris injury. The damages of the cornea were marked near the surface, stretched to more deeper layers, and damage zones were extended from the epithelium for 2.84 micrometers wavelength to whole cornea thickness for 1.32 and 1.54 micrometers wavelengths and have intermediate position for 1.96 and 2.09 micrometers wavelengths, depending on the corneal absorption coefficient. Quantitative results of threshold energy levels were calculated by probit-analysis. The radiant exposure (HD₅₀), that cause the threshold coagulation changes in cornea with 50% probability was determined for the beam diameter (irradiance diameter) of 2 mm and for 1.32; 1.54; 1.96; 2.09 and 2.84 micrometers wavelengths. Values determined were (2.4 +/- 0.2) X 10; 7.2 +/- 0.6; 2.9 +/- 0.5; 3.7 +/- 0.2; (1.9 +/- 0.4) X 10^-1 J/cm². These values are well-correlated to corneal absorption coefficients. The absorption coefficient the higher, the value HD₅₀ the lower and the `danger' for ocular structures damage also the lower. This fact is needed to be taken into account, because of normative documents did not reflect it in 1.3 - 3.0 micrometers wavelength range. The obtained results may be used for development of new clinical laser applications and refinement of the laser safety standards.

Light scattering as a basic process determining laser beams transport within eye tissues is analyzed. Theoretical and experimental results for human eye lens and sclera optical and spectral characteristics are presented.

It reports the statistic results of the long-term research of the different principles and methods of the laser coagulation both in its `monochromatic' variety and the stage-by-stage lamellar method of different laser application for radical obliteration of the pathological objects with different depth of location in the eye bottom.

The authors report about the undoubted effectiveness of the clinical use of the method of the laser fixation of a dislocated lens for fixing its geometrical position and stabilization of the visual functions of the damaged eye performed with the aim of anatomophysiological rehabilitation of 132 patients. It the later period (after 3 - 10 years) the normalization of the hydrodynamics of the eye and the steady stabilization of the glaucoma process is observed. Complications were not detected.

During last years the growing interest to YAG-laser capsulotomy in microsurgery treatment of cataracts should be noticed. For the first time the operation of laser phacopuncture was done by V.S.Akopyan in 1975 during the experiment on rabbits. Then in 1 976 M.M.Krasnov and V.S.Akopyan used the frontal laser capsulephacopuncture in treatment of so called "soft" forms of cataract. 290 patients were under observation (300 eyes). They were departed on two groups. The first one - the patients with immature age cataract (98 eyes) and complicated cataract (52 eyes). Extracapsular cataract extraction was produced by the common method of anterior capsule cutting by cystotome. The second group was consisted of patients with immature age cataract (104 eyes) and complicated cataract (46 eyes). In this group capsulotomy was produced using YAG-laser before microsurgery operation. The causes for complicated cataract in both groups were diabet, uveitus, complicated myopia, tuberculesis and professional diseases. The ages of patients were the following: younger than 60 years - 41 in first group, 26 in the second one; more than 60 years - 103 in first group, 109 in the second. In the first group were 59men and 86 women, in the second - 57 men and 91 women. The cause for operation were eye vision sharpness lowering more than 0,1. Extracapsular cataract extraction to the patients of first group was produced with anterior capsule cutting by cystotome with the following crystalline lens nucleus removing and crystalline lens masses washing out. In the second group capsulotomy was produced by YAG-laser before the microsurgery operation stage.

Proceeding from experiments and experiences of the 2500 operations, the patients suffering from different eye ground diseases were subjected to with the use of the first Russian Ga-As diode laser, it was shown that the problems of its clinical use, related to the developing character of the burn, are easily resolved by avoiding laser directly projected rays that shield the place of coagulation and by applying a mark of light being formed by means of partial shielding of the eye ground surface not being subjected to coagulation. Application of such a mark also eases the painfulness associated with the diode coagulation, mostly caused by hyper coagulation, which happens due to the determination problems arising while attempting to evaluate the degree of the burning under the light of the bright laser monochromatic directly projected ray.

The emission of a pulse-periodic laser on alumo-ittrium garnet applied for preventive and medical treatment of a capsule contracture round implanted prostheses in xenoplastics is described in the present paper. The results obtained testify to a high efficiency of suggested method.

One of the leading problems of gastroenterology of our country is the task of ulcerative disease of the stomach treatment, duodenum treatment and diseases of large intestinal treatment. In spite of introduction of clinical practice the new anti-ulcerous preparations, the process of ulcerative disease of the stomach treatment remains a long process and makes in average about 2 - 4 weeks for acute ulcers and 2 - 3 months for chronic ulcers. In accordance with a world statistics an ulcerative disease of the stomach remains a very spread sickness (on the average 5 cases on 1 thousand persons), and even in the majority of countries at the last decade an increase of number of illness, stipulated by breach of ecology, stress, general worsening of human living conditions took place. Notice that the growth of exposure of morbidity in the area of alimentary tract to a certain extent is connected with introduction into diagnostics practice the endoscopical methods during a checkup of patients. Within Russia the statistics data give the following picture: (1) 500 - 700 persons per 100 thousand of inhabitants have an ulcerative disease and 15 - 20 persons from them have a steady resistance to an anti- ulcerative medicamental therapy. (2) At complex and electoral treatment of ulcerative disease patients with various preparations an epithelization have 60 - 94% of patients in the time of 20 - 48 days. (3) Insufficient efficiency of means of a conservative treatment results in that 50% of the sicks need urgent operations, sometimes at complicated for them conditions.

On tissue scattering parameters determination illustrating sensitivity and dynamic range of frequency-domain method using a mode-locked YAG-Nd laser and modulated injection GaAs laser were performed. For microwave range (0.1 - 2 GHz) both methods in application tissue and water-milk mixtures, latecs investigation comparable results were obtained.

The paper presents the results of electron-microscopy study of dental tissues, prepared by erbium laser radiation.

Involving high-power lasers into clinic medicine significantly extended the possibilities of the endoscopic surgery, which in a number of cases becomes a serious competitor to the traditional surgical methods of treatment1,2 Endoscopic surgeiy lowers the intervention risk, reduces the terms of patient's hospital treatment, the patient s activity can be restored in a shorter post-operational period and a possibility appears of carrying out complex operatirns in ambulance conditions. Endoscopic operations nowadays are made using mostly a continuous YAG: Nd laser with operating wavelength 1.06 tm. However, there exist serious restrictions on use of this type of radiation for the endoscopic surgical interventions at the gastrointestinal organs. They are connected with wall perforation risk . Endoscopic using of a cO-laser, which works as an excellent scalpel in general surgety, is connected with technical difficulties of 10.6 jim radiation transmission by a flexible light guide. Moreover, the the hemostatic properties of this kind of radiation are rather limited. The specified above reasons stipulated that the practical medicine be interested in solid YAG-cr-Tm: Ho lasers with wavelength range of 2 im and their application in the endoscopic surgeiy. This report consists of two parts: experimental and clinical ones. The experimental data presents the character of pulse-repetitive YAG:Nd and YAG:cr,Tm,Ho lasers radiation action in comparison with the radiation from cwYAG:Ndlaser. The second part presents the results ofthose lasers application to endobronchial surgery.

The technique of 3D peptide-bonded biopolymer structure modification is proposed. 3D serum protein structure controlling is realized by IR-induced intramolecular vibration excitation of peptide bounds functional groups (C equals O, NH), connected with the hydrogen bond.

Due to widespread therapeutic settings applying low-intensity He-Ne lasers, researchers were forced to decide problems of developing express-techniques for controlling laser therapy effectuality, optimizing this treatment method and selecting an individual irradiation dose. biochemical techniques are non-effectual for these purposes since low-intensity He-Ne lasers do not induce photochemical transformations in blood1 In this connection, it is necessary to note that optical properties of biological liquids depend on their chemical composition and the structure separating supermolecular arrangements of ui2. Thus, if chemical composition of transparent bioliquids is invariable, methods of analysing their optical properties can be used for analysing their structural dynamics. In the present paper, results of studying changes of refraction index (RI) of blood plasma irradiated by a low4ntensity HeNe laser are shown and a possibility of using the data obtained in laser therapy are analysed.

Basic pathogenic research as well as the studies of clinical therapeutic aspects dealing with the long-term gamma radiation effects are of utmost significance nowadays. The main goal of the present study was to establish the capability of low-energy laser insolation to oppose the free radical oxidative chain reactions inherent to the effects of radiation. Adequate doses of low- energy laser insolation were shown to produce positive effects upon the metabolism similar to those of pharmacologic radioprotectors.

The rapid growth of electrooptics and laser technology has increased the possibility of human exposure to optical radiation and concern about health effects. The much attention has to be focused on the creation of the safety program that assures the safe use of lasers taking into account the possible side effects of laser therapy. In order to investigate the imunotropic effect of lasers the experimental model which was close to the therapeutic modes has been used for IR laser (the wavelength 890 nm) and He-Ne laser (the wavelength 633 nm). The immune system underwent changes testifying about the breaches in the processes of maturation and migration of the lymphoid cells, also the alteration of receptors as a sign of the membrane damaging effect of lasers was seen.

Plasmapheresis in pulmonology is one of the leading methods of extracorporeal detoxification of patients with purulent lung and pleura diseases. However this method causes a decrease in patients' leukocyte level and humoral immunity indices. The medico-biological research conducted at the State Scientific Center of Pulmonology demonstrated that a combination of plasmapheresis with additional irradiation of the patients' reinfused erythrocyte mass with low intensive He-Ne laser light with the wavelength of 0.63 mkm considerably reduces the probability of these complications. It may be due to the fact that laser irradiation of autologous erythrocytes induces local and general stimulation, favoring in this way the inflammatory process involution. The suggested method of plasmapheresis was used in the process of treatment of 76 patients with lung abscess, empyema, purulent mediastinitis, sepsis. The essence of the method consists in irradiating with He-Ne laser the last portion of the erythrocyte mass (130 - 170 ml), diluted with saline, during its reinfusion in the course of a routine plasmapheresis. The positive impact of practical application of the above method allows to characterize it as highly effective for treatment of purulent diseases in pulmonology.

The results are presented of the investigation of the tonic state of muscles of normal and sick subjects by using a laser specklometer whose principle of operation is based on speckle-optical measurements of state of the human skin.

The paper describes a method and an experimental setup for biovibrations monitoring using coherent fields diffraction. The results of in-vivo human pulse wave measurements are presented. The computer modeling of the considered processes was carried out. The proposed measuring system output characteristics were analyzed. The sensor designed allows to perform a direct recording of a pulse beating.

The median photons path needed for the formulation of the tomographic problem is revealed in the photon diffusion equation solution as well as probability density distribution of single photons instantaneous position deviation from the median path. The mentioned distribution defines the resolution of the strongly scattering medium tomographic investigation.