In an effort to determine the objective parameters of 'asthenopia' or 'eye strain' in video display terminal (VDT) workers, a modified photostress- test which was a combination of the regular photostress test and the test of contrast sensivity with the Pelli-Robson chart was performed. This measurement was based on two conditions at the same time while working with computers. The first condition was a short working distance which relates to 'transient myopia' and induced contrast sensitivity disturbance, and the second was light exposure from a VDT which was analogous to a photostress test. The parameter used was 'recovery time'. The population for this study were VDT workers which had asthenopic complaints and were divided into two groups, the study group (high exposed VDT) and the control group (low exposed VDT), with 42 subjects in each group. The study findings showed a decrease in recovery time during one hour of work in both groups-operators and nonoperators. This value might be increased again after two hours of work, but when work time was within 1-2 h if did not result in asthenopia. The deviated recovery time of 19.78% indication a greater risk of asthenopia (p<0.05). Sex, job functions as operators, age, the Hb level and environmental factors as a whole tended to affect the incidence of asthenopia.
|Number of pages||6|
|Journal||Journal of Occupational Health|
|Publication status||Published - Oct 1999|
- Contrast sensitivity test
- Photostress test
- Recovering time