Risk factors for Computer Vision Syndrome (C.V.S.) among operators of two call center in São Paulo, Brazil

Introduction
The visual syndrome associated with computer use (CVS) is an eye disorder that is currently being studied for its high prevalence worldwide and is becoming increasingly common in some professions. This study aimed to estimate the prevalence of this syndrome among operators from two call centers located in São Paulo (n = 476).

Methods
A quantitative cross-sectional observational study was performed, by means of a questionnaire containing questions about: socio-demographics, lifestyle habits, occupational history, work status, satisfaction factors, discomfort factors at work and psychosocial factors related to work. The case definition was based on the concept of Computer Vision Syndrome from Blehm (2005), i.e. the presence of one or more ocular specific symptoms occurring in a frequency greater than or equal to "sometimes". Statistical analysis was performed for absolute and relative frequencies and examined the association by chi-square. The variables that showed p < 0.20 or which were described in the explanation of eye disorders were included in multiple regression analysis. In the final model remained variables that showed descriptive levels below 5% (p < 0.05).

Results
The symptoms reported were: visual fatigue (73.9%), “heaviness” in the eyes (68.2%), “burning” eyes (54.6%), tearing (43.9%) and vision impairment (43.5%). The prevalence of CVS among operators was 54.6%. Other associations found were: being female (OR 2.6, 95% CI 1.6-4.1), lack of recognition during work (OR 1.4, 95% CI 1.1 to 1.8); organization of work in telemarketing (OR 1.4, 95% CI 1.1 to 1.7) and work demands (OR 1.1, 95% CI 1.0 to 1.3).

Discussion
This study showed the importance of organizational characteristics and psychosocial factors at work as related to the presence of CVS in telemarketing operators.