[The assessment of the noise factor and the state of the auditory analyzer in workers in metal rolling production]. / Otsenka na shumoviia faktor i sustoianieto na slukhoviia analizator pri rabotnitsi ot prokatnoto proizvodstvo.

At main workplaces in F. "Stomana" (Pernik City) sorting and sheetrolling works, measurements and evaluation of the noise factor were carried out, and hearing sensitivity of workers was investigated in 229 subjects of mean age 36.1 +/- 9.8 years and mean occupational experience 9.7 +/- 7.4 years. Findings at workplaces indicated presence of noise of excessive equivalent levels and pulsing nature varying in degrees. Hearing thresholds for 4 and 6 kHz and average speaking frequency were elevated, and the proportion of subjects with hearing threshold above 30 dB for all frequencies tested was larger among the job groups of roller workers, furnace men, cutters, crane workers, markers, packers, quality control surveyors, and dispatchers as compared to subjects working at lower noise levels or exposed for shorter times to intense noise, notably, operators, fitters, welders, electrotechnicians. Regression analysis revealed the dynamics of change in hearing sensitivity to be more closely related to age than to duration of occupational experience.

[Changes in the functional state of the visual analyzer in operators working with video display terminals]. / O sdvigakh v funktsional'nom sostoianii zritel'nogo analizatora operatorov pri rabote s videoterminalom.

Research in laboratory and on-site conditions was performed to establish correlations between the visual analyzer's functional shifts in display operators, and the duration of work, the type of the screen used (coloured or non-coloured), the duration of the eyes, fixation on the screen, as well as sex related differences.

[Functional changes in the visual analyzer of female personnel in quality control of ampules]. / Promeni vuv funktsionalnoto sustoianie na zritelniia analizator pri kontrol'orki na ampuli.

The state of the visual apparatus as well as the changes in the functional state of the visual functions, due to the work performed, were studied in 60 female workers checking up the quality of ampoules. The eyes were clinically examined with a view to detection of eye diseases. The results revealed a high percentage of complaints from the visual system, high visual strain, due to the small size of the details to be checked and the irregular illumination of the visual field and the high rate of work. Pathological changes were found in the anterior segment and fundus of the eyes in a great number of the workers. Recommendations are proposed for the optimization of the work in that kind of activity.

[Visual fatigue during work associated with increased visual loading]. / Zritelna umora pri trudova deinost, svurzana s uvelicheni zritelni natovarvaniia.

Visual perception is an important factor of human activity. The quality of production activity of the worker depends on its accuracy and speed. Representative groups of workers with various occupational activities, associated with considerable loading of visual system, were systematically examined by clinical and functional methods in the course of several years. A total of 765 subjects were examined, aged from 20 to 55 and a length of service from I to 25 years. The results reveal considerable alterations in visual system within one working day. The most general features of those alterations are as follows: elevation of the threshold of electric sensitivity towards the end of the working day, reduction of light-distinguishing and colour distinguishing sensitivity, the closest point of clear vision is removed father, unproper ergogram with an ascending course, reduction of fusion ability towards the end of the working day, etc. A great part of the subjects over the age of 40, were established to have uncorrected presbyopia, leading to high strain of accommodation and convergation, followed by visual fatigue. The adaptation of visual system to labour conditions is the best at the age range 25-35. The alterations in the visual function are far better manifested in the age group over 40. The determination of fatigue degree and the time of developing of the first alterations is of particular significance for the introduction of additional rest for rehabilitation.

[Effect of age on visual functions]. / Vliianie na vuzrastta vurkhu niakoi zritelni funktsii.

The differential color-distinquishing threshold, functional reserves, visual acuity, distance to the nearest point of clear vision and positive part of absolute accomodation were measured in working people in active age. A certain deterioration of these visual parameters with advancing age was recorded, which was practicall manifested by decreased ability for fine distinquishing of details, color and relief, when continuous work at short distance was performed. The greater variations in the functional state of vision at the of the working day in elderly workers require measures to be taken to alleviate work, in conformity with the age characteristics of the visual functions.