Scand J Work Environ Health 1995;21(5):382-390 pdf
https://doi.org/10.5271/sjweh.53 | Issue date: Oct 1995
Visual dysfunction among styrene exposed workers
Objectives The present study was undertaken to examine the relation between visual functions and occupational exposure to styrene.
Methods A total of 128 workers (85% of the total population), from three glass-reinforced plastics plants in Canada, agreed to participate in the study. Environmental and biological measures were made on the day(s) prior to the assessment of near visual acuity (National Optical Visual Chart), chromatic discrimination (Lanthony D-15 desaturated panel) and near contrast sensitivity (Vistech 6000). The analyses were performed on 81 workers with near visual acuity of at least 1 minute of arc at 0.5 m.
Results Subjects were relatively young [29 (SD 8) years], with little seniority [5 (SD 4) years]. Styrene exposure for 8 hours ranged from 6 to 937 (first quartile 21 mg m-3, third quartile 303 mg m-3), depending on the job site. The end-shift concentrations of urinary mandelic acid ranged from nondetectable to 1.90 mmol mmol creatinine-1. Significant positive relations were found between internal and external styrene exposure measurements and color vision loss adjusted for age, alcohol consumption and seniority in a multiple regression analysis. The multiple regression analysis also showed that end-shift concentration of urinary mandelic acid was inversely related to contrast sensitivity at 6 and 12 cycles degree-1. Logistic multiple regression models indicated that end-shift concentration of urinary mandelic acid was related to the prevalences of blurred vision, tearing and eye irritation. Conclusions These findings suggest that there is a positive relation between styrene exposure and early color and contrast vision dysfunction.