Cluster randomized controlled trial of a workplace intervention to prevent computer vision syndrome and dry eye syndrome in workers using video display terminals
Prevention of computer vision syndrome and dry eye syndrome in workers using video display terminals
Stratified randomization by center will be performed to assign clusters to the intervention or control group. In the control group clusters, only the standard routine activities carried out by the Occupational Health Service (OHS) will be implemented. In the intervention group clusters, in addition to these usual activities, actions will be undertaken across the three levels of prevention (primary, secondary, and tertiary), along with a health promotion component. In all cases, physical, anatomical, and physiological differences between men and women will be considered. * Primary prevention actions: - An ergonomic assessment of the workstation will be conducted, taking into account individual worker characteristics, habitual computer posture, and environmental conditions. - Measurements will include the eye-to-screen distance and neck posture, assessed via direct observation. Two photographs will be taken: one from the sagittal plane while the participant is seated, and another from a perpendicular angle to the screen. Using Qcad Trial software version 3.19.2, the following angles will be calculated: the eye-to-screen angle (α), the viewing angle (α′), and the screen tilt angle relative to the horizontal (β). - Environmental conditions will also be evaluated. Dry temperature and relative humidity will be measured using a thermohygrometer (PCE-WB 20SD), and illuminance will be assessed using a luxmeter (ISO-TECH ILM 1337) at three different points within the workstation, with the average recorded. Additional assessments will include glare, screen reflections, localized lighting, and air conditioning status. - Ergonomic and environmental adjustments will be made based on the standards set out in the Spanish Royal Decree 486/1997, Directive 90/270/EEC, the INSST guide (2021), and ISO 11226:2000. When workstation setup is suboptimal, distances, angles, and heights will be modified. If ambient conditions (temperature, humidity, lighting, air velocity) are inadequate,
Participants must have been working in the selected cluster (independent building) for at least the last year, hold a full-time contract, and be actively employed at the beginning of the study.
1. Workers under 18 or over 70 years old; 2. Workers not currently employed in the selected cluster (independent building) for at least the past year; 3. Workers with part-time contracts; 4. Individuals who, although belonging to any of the intervention or control clusters, are not actively employed at the beginning of the study. 5. Individuals who do not consent to sign the informed consent document.