Work with Visual Display Units and its effect on the eye

Purpose
To examine the condition of visual functions of computer operators and the influence of work at VDU on visual functions and on self-satisfaction of computer users. The results of such studies can be used to determine the range and methods of carrying out qualification and prophylactic examinations.

Material and methods
The investigation involved 5 groups consisted of 241 people at the age 21 to 60 years (37 years on the average). A short-term visual work (1-hour work with computer) was the subject of the study of the first group. The influence of 6-hour work at VDU on the eye was studied in case of the second group. The subjects of the third group performed a routine office work without computer. The relation between the type of visual discomfort and working conditions (eg. natural and artificial lighting) was examined with the fourth group, while the examination of the fifth group aimed at revealing whether the correction of ergonomic conditions of workplaces had an effect on the reduction of complaints and on visual functions (the research was performed one year before the modernisation of workplaces and one year after). The study of visual complaints carried out with the use of questionnaires included the evaluation of visual functions (like: visual acuity, refraction, convergence, accommodation, critical flicker frequency, contrast sensitivity, binocular vision), and visual system and the assessment of ergonomic conditions of workplaces provided with VDUs.

Results
The work at VDUs caused a statistically considerable deterioration of convergence, accommodation, near and distant phoria, contrast sensitivity and critical flicker frequency.

Conclusions
The reduced efficiency of examined functions may lead to visual discomfort of VDU operators. The improvement of ergonomic conditions of workplaces and individual adjustment of work-time has a favourable effect on the reduction of reported eye discomforts.