Introduction:

According to the European Working Conditions Survey, 37 % of workers are using devices with display screens almost the whole working day, and 20 % of workers use them for at least a quarter of its working day. The health surveillance of these workers is still based on the specific protocol of 1999. From then on, there have been remarkable changes in the design and performance of the work equipments. Many workers from different working areas have introduced these technologies to their common tasks and non-work activities. Likewise, display screens, in different sizes and formats, have also been incorporated into the daily life of many people. In view of these changes, it is necessary to update this health surveillance protocol in order to optimize the prevention of the exposed workers.

Aim:

The aim of our work is not only to value the behavior of the CVSS17 questionnaire assessing the visual and ocular system through a specific physical examination, but to determine its usefulness as a screening element in order to monitor the health of the workers professionally exposed to display screens.

Method:

Cross-sectional study carried out between September 2016 and February 2017, with the results of the health examinations of workers professionally exposed to display screens in the offices of the Institut Català de la Salut. Initially, the workers completed the CVSS17 questionnaire, developed as a scale to measure the computer-related ocular and visual symptoms associated with the use of PVD. Afterwards, the health surveillance took place. This involved different maneuvers and diagnostic tests in the oculo-visual sphere. A new variable was built up with these data; we called it “overall visual disturbance”, used as a reference test (gold standard) to calculate the validity of the questionnaire and the construction of ROC curves.

Results:

A total of 184 individuals answered the questionnaire. 150 (81.52%) underwent voluntarily the health examination. Their data were included in the study. 102 of them were women (68.0%) and 48 men (32.0%), with an average age of 49.3 years and a standard deviation of 8.5 years.

The results of the CVSS17 questionnaire showed symptom levels (SL) from 1 to 5 respectively of 37 (24.7%), 42 (28.0%), 41 (27.3%), 25 (16.7%) and 5 (3.3%) individuals. Symptomatology Level grade 6 was not obtained. When performing the ocular exploration, 6 individuals (4.0%) showed alteration of the near visual acuity, 34 (22.7%) showed an alteration in the main gaze position, 13 (8.7%) showed an alteration of the macular overload test, 15 (10.0%) showed an alteration of the near conversion point, 13 (8.7%) an alteration of the Amsler test, 50 (33.3%) had altered the Schirmer test and 5 (3.3%) presented alteration in the color vision. Overall, 87 individuals (58.0 %) showed disturbances of at least one of the visual-eye examination tests.

The ROC curve adjustment from the “overall visual disturbance” variable did not show significant differences [Area under the curve of 0.47 (95% CI: 0.37-0.57, p = 0.51)], so that the probabilities of correctly classify a pair of individuals as one healthy and another pathological are minimal.

Conclusions:

No relationship has been found between the intensity of these symptoms and the specific ophthalmological clinical examination by using a questionnaire designed to measure the ocular and visual symptoms associated with the use of display screens.

The presence of clinical alterations has been significantly related with the age of the individuals. Female gender has been associated with a higher manifestation of the oculo-visual syndrome symptoms.

CVSS17 is a tool that can be used to characterize and monitor the ocular-visual symptoms related to the use of display screens. Used as a screening tool, this tool reaches a sensitivity of 0.838 while its specificity would be only 0.140.