Revista de Igienă şi Sănătate Publică, vol.61, nr.1/2011 – Journal of Hygiene and Public Health
9 rate was 62 – 82 beats/minute, according to the sedentary character of the work. The neuropsychic strain is important, both sensorial and mental. The sensorial strain is especially visual, many visual functions participating in the work process: visual acuity to near and far and between near and far (the distances are repeated: of 30 – 120 cm), ocular movements, contrast and chromatic sensibility, perception velocity, retina adaptation, visual field. The auditory strain is determined by the necessity to discern the auditory information of the CP or other auditory signals produced in the installations. The mental strain is determined by the attention (especially distributive), memory and technical thinking participation in the activity. The concentrated and distributive attention is very important (visual attention) for receiving correctly the information. The technical thinking intervenes to establish the characteristics of the CP information, to understand the disturbance of the
installation running, to take the correct and necessary decisions. The work responsibility and monotony increase the neuropsychic strain. There is a permanent vigilance state. In case of special events (incidents, especially occurrences in installations), the organism strain increases much. The heart rate is high, of more than 100 beats/minute. The performances of the neuropsychic indicators have decreased in 76 – 97% of the subjects during the work (p < 0.001) – Table 1, Table 2, Figure 3. That decrease makes evident the visual and general fatigue of the operators’ organism. The performance of the “Optotype” test and CFF decreased especially after 4 hour of work. In case of a normal organism performance, the urinary release of catecholamines increases to 2 hours p.m. the causes for the decrease during work at the CP are the high neuropsychic strains and the activity without motor discharge (p < 0.002 and 0.006) (Figures 3 and 4).
Table 1. Subjects with increase or decrease in the neuropsychic tests performances at the work’s end in comparison with the values before the beginning of the work Subjects % Indicators Increase
Decrease
61 60 57
39 40 43
Blink frequency, no/min
72
28
CFF, Hz/s
12
88
97 40
3 -
33
58
Accommodation RE Accommodation LE Convergence BE
Distance cm
Optotype test
Time, Mistakes, number
Weston test, EC RE – right eye LE – left eye
BE – both eyes EC – exactitude coefficient
The neuropsychic indicators, including the visual indicators, highlight at the end of the work shift the following data: the increase
of the ocular accommodation and convergence distances (decompensate ocular fatigue), blink frequency increase,