Assessment of Acquired Color Vision Impairment among the Workers Exposed to Mixed Organic Solvents in an Automobile Manufacturing Company

Background and Objectives: Solvents are widely used in industries. Occupational exposure to organic solvents can lead to dysfunction of the nervous system. Since color-vision impairment can be a sensitive and early marker of neurotoxic damage, this study was designed to determine the influence of chronic occupational exposure to organic solvent mixtures on color vision. Materials and Methods: This discriptive study was conducted in an automobile plant in 2008. Workers employed in the painting saloon were considered as exposed and workers in the assembly were used as non-exposed. A questionnaire containing required data of workers was administered. After considering exclusion criteria, color vision of 157 exposed workers was compared with 174 non-exposed worker, using X2 test. Results: The percentage of acquired dyschromatopsia was 43% in the exposed group and 3.45% in the other group. The percentage of acquired dyschromatopsia exposed employees was significantly higher than that of the non-exposed subjects (OR = 21.95, CI = 9.16- 52.57) (p<0.001). Mean of the color-confusion index for exposed employees was significantly higher than that among the other subjects (1.32 and 1.02 respectively) (p<0.001). The logistic regression for color confusion index indicated that the color-confusion index was positively related to exposure to mixed organic solvents (p<0.001). Conclusions: The results of this study suggested that chronic occupational exposure with mixture of organic solvents, in higher amounts of permissible levels, can cause acquired color vision defects. Key words: Organic Solvent, Color Vision, Occupational Exposure   Funding: This study was supported by Iran Univrsity of Medical Sciences. Conflict of interest: None declared. Ethical approval: The Ethics Committee of Iran Univrsity of Medical Sciences, approved the study.