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[Health Surveillance Guide of workers using video display terminals: evaluation from a visual health perspective].

BACKGROUND
Visual health surveillance is essential in the protection of workers who use video display terminals (VDT). In Spain, the most used is the Specific Health Surveillance Guide published in 1999 by the Ministry of Health. The increase of the scientific production upon computer related occupational visual hazards and the experience in its applicability during the last decade justify the aim of this work: reviewing the quality of the guide from the point of view of visual health.


METHODS
A consensus strategy was used among nine experts by means of a mixed groupal technique in two consecutive stages combining some aspects of the Delphi method and of the nominal group: individual evaluation of the guide using the consensus guide made by the authors based on the AGREE instrument and the subsequent meeting in order to reach an agreement and to fix the final recommendations for improving it. For the analysis the standardized score of the review domains was calculated: scope and purpose, stakeholder involvement, rigour of development, clarity and presentation and applicability. It was also calculated for the items.' Concordance in the answers of the experts was also analyzed.


RESULTS
All domains obtained scores under 50%. The applicability, rigour and stakeholder involvement during the development of the guide, where the most deficient domains. Six out of the nine experts would not recommend the guide and think it should be remade.


CONCLUSIONS
The guide does not reach the necessary quality for the surveillance of the visual health of the workers who use VDT. Efforts must be focussed to improve the guide.