In Hungary, the school-age prevalences of severe visual handicaps and of profound childhood deafness have been estimated to be about 6/10(4) and 10/10(4), respectively. Most of these conditions have onset at birth or in early childhood and are aetiologically heterogeneous. Severe visual handicaps are grouped under 11 aetiological categories, their relative contributions to the prevalence being: perinatal damage syndrome (20%; half of this is due to retinopathy of premature infants), cataracts (15%), choroidoretinal degenerations (15%), congenital abnormalities of the eye (15%), syndromes (10%), high myopia +/- retinal detachment (7%), postnatal causes (5%), nystagmus (5%), optic atrophy (4%), bilateral retinoblastoma (2%) and prenatal causes (2%). Overall, Mendelian conditions (included under many of the above) account for about 50% with relatively more autosomal dominant than autosomal recessive and sex-linked entities, and acquired causes account for about 40% of the cases studied. No aetiology could be assigned in 10% of the cases. For profound childhood deafness, the rank order of the aetiological categories is: autosomal recessive entities (34%), postnatal causes (22%), perinatal causes (19%), autosomal dominant entities (17%), prenatal causes (5%) and unknown causes (3%). Severe childhood visual handicaps are responsible for about 60 years of loss of life per 10(4) live births and about 400 years of impaired life per 10(4) live births. Genetic causes account for one-quarter of lost life years and three-quarters of impaired life years. The comparable estimates for profound childhood deafness are: about 240 years of life loss per 10(4) live births (again, about one-quarter due to genetic causes) and about 640 years of impaired life per 10(4) live births (about one-half due to genetic causes). In all these calculations, it has been assumed that the average life expectancy at birth for an individual in the population is 70 years.

This paper briefly reviews the authors' experimental and clinical use of lasers over a 20-year period, during which laser effects on 15 biological systems were studied. Low-energy laser radiation was found to have a stimulating effect on cells, and high-energy radiation had an inhibiting effect. The application of lasers to stimulate wound healing in cases of nonhealing ulcers is recommended.

Coherent and polarized laser light has a special, and until now unexplained, effect on biological systems. This has been called biostimulation. A hypothetical model based on experimental facts to explain this effect is proposed. The substance of this model is that the polarized light reorders the polar heads of the lipid bilayer in the cell membrane, the lipid bilayer being near phase transition. This change in the quality of the cell membrane influences all the processes closely connected with it. These process modifications may yield an explanation for biostimulation.

The biostimulatic effect of laser radiation was proved in animal investigations and also observed in 259 patients with disturbed wound healing. Laser rays can be applied without any risk in patients. The therapy was successful in over 90% of the patients. The duration of the therapy amounted to 10 to 12 weeks on an average.

In vitro experiments with human lymphocytes showed that if irradiations with coherent light of a He-Ne-laser were performed an immune suppressor effect is obtained. Using incoherent light of the same wavelength, effects only occur (80% compared to the laser) if the light is linear polarized.

: In vitro experiments with human lymphocytes showed that if irradiations with coherent light of a He-Ne-laser were performed an immune suppressor effect is obtained. Using incoherent light of the same wavelength, effects only occur (80% compared to the laser) if the light is linear polarized.

In-vitro-Experimente an menschlichen Lymphocyten zeigten, daß durch Bestrahlungen mit kohärentem Licht eines He-Ne-Lasers eine immunsuppressive Wirkung erzielt wird.

The immune-suppressive action of laser rays was studied in directly irradiated human lymphocytes. It was found that the argon ion gas laser is more effective in the range between 488 and 501 nm than at other wavelengths and than the He--Ne laser (632 nm) of the same performance. It is assumed that the suppression of some undesirable immune reaction (auto-aggressive process) contributes to the stimulating effect of laser rays on wound healing.

An increased acetylcholine release could be produced by ruby laser from the Auerbach plexus of the guinea-pig ileum.

Favourable results have been achieved by low energy He--Ne gas laser in the treatment of coumarin-induced extensive skin necroses. Two illustrative cases are reported.

Serum complement activity, immunoglobulin levels and the circulating auto-antibodies were studied in the course of laser treatment of 20 cases of crural ulcer. After temporary changes a normalization of the humoral immune response was observed in the healing cases, while in the stagnating ones opposite trend was manifest. In none of the groups were detected circulating auto-antibodies against the investigated antigens.

The authors studied the process of muscular regeneration on experimental models after simple muscle injury and under the effect of low-energy laser-irradiation. It is stated that the stimulating effect not only accelerated the wound healing, but most likely influenced also the qualitative improvement of regeneration.

The effect of laser beam on the survival of skin allotransplants has been studied. Irradiation of the donor skin and of the recipient graft bed improved the survival of the graft. The graft protecting effect of anti-thymocyte serum was considerably enhanced by laser irradiation.

In Ohrkammer Modellexperimenten konnten die Wundheilung wie auch die Gefässformation mittels Laserstrahlen wesentlich stimuliert werden.