Introduction Acquired dyschromatopsia is an early and sensitive marker of ophthalmic neurotoxicity due to chronic exposure to various chemicals. The overall objective of this research was to identify changes in colour vision acquired the personnel occupationally exposed (POE) to a mixture of OS (benzene, toluene, xylen –BTX-).

Material and methods A cross-sectional study was conducted in two groups of workers; one occupational exposure to a mixture of OS and one without exposure to the chemical industry. The participants answered a questionnaire to explore risk factors acquired discromatopsia. Subsequently, the test Lanthony 15 desaturated (LD-15) in each eye was used to determine the ability of colour discrimination and Confusion Chromatic Index (CCI) was quantified. All ratio >1 was interpreted as abnormally increased. The data univariate and bivariate analysis were submitted. Association tests were implemented (t test, Chi² and logistic regressions).

Results The total population was 142 workers, 5.4% of whom had a profile consistent with congenital dyschromatopsia and were excluded from the final analysis. The group of 73 workers was exposed, while the unexposed group was 65. The average age was 43.9 years (±10) and 42.7 years (±12), respectively. The prevalence of acquired dyschromatopsia in both eyes was higher for the exposed group; 8% in right eye and 9% in left eye, however, no statistically significant differences from the unexposed group. Quantification of CCI was slightly higher in the exposure group (1.09) compared to the group without exposure (1.08), although the differences between groups were not statistically significant (p=0.73).

Discussion The results are consistent with those of other investigators; ICC ratio is higher in the exposed group, as well as the prevalence of acquired dyschromatopsia, being the most common for both groups.