Impaired colour discrimination among workers exposed to styrene: relevance of a urinary metabolite.

Abstract

Objectives-To survey the loss of colour vision among Japanese workers who have been exposed to styrene concentrations currently considered low (about 20 ppm). Also to assess the effects of styrene by examination of the nature of the relation between disorder of colour vision and age, alcohol consumption, and other variables. Methods-Colour discrimination was examined in 64 male workers exposed to styrene (mean age; 38'0, mean exposed years; 7'0) and in 69 controls (mean age; 38.0). A standardised questionnaire was adopted to collect work history, occupational or non-occupational solvent exposure, alcohol consumption, and drug use. The results of the test were expressed as the colour confusion index (CCI). Results-The mean atmospheric styrene concentration was about 20 ppm. The mean urinary concentration of mandelic acid was 0-22 gil. There was a significant difference in CCI between exposed workers and age matched controls. Colour vision of workers whose concentration of urinary mandelic acid was > 0'42 gil was significantly impaired when compared with workers whose concentration was <0'42 gil. Multiple linear regression analysis that controlled confounding variables such as age, alcohol consumption, smoking, and educational attainment showed that the CCI was significantly related to the concentration of urinary mandelic acid. In both exposed workers and controls, the types of defects were mostly blue-yellow loss, although a few subjects showed complex loss. No one showed only red-green loss.Conclusions-These findings suggest that exposure to moderate styrene concentrations can lead to impairment of colour vision, and that there is a significant correlation with the urinary metabolite of styrene.(Occup Environ Med 1995;52:534-538)

Increased acquired dyschromatopsia among solvent-exposed workers: an epidemiology study on 249 employees of an aluminum-foil printing factory

“…The published studies often take the length of service or duration of exposure into consideration as a re¯ection of the past. Several authors [5,8,10] who included this indicator in their regression models found no signi®cant link with the CCI, whereas they did ®nd one with current exposure. Most, however, took the precaution of carrying out the tests at the beginning of a period of exposure so as to avoid the eects of subacute exposure.…”

Impairment of Neurobehavioral Function and Color Vision Loss among Workers Exposed to Low Concentration of Styrene. A Review of Literatures.

“…The previous threshold limit of exposure to styrene was 50 ppm in the U.S.A. (until 1997) and Japan (until 1999). However, even exposure to concentrations lower than this limit, might lead to the impairment of color vision 15,17,18) . Some researchers examined the dose response, and found that styrene could induce dose-dependent color vision loss 15,16,18) .…”

“…The results of these studies showed that such impairment often occurred among the workers exposed to styrene ( Table 4). The interrelationship between the degree of exposure to styrene and the impairment of color vision was investigated 6,[15][16][17][18][19] . The previous threshold limit of exposure to styrene was 50 ppm in the U.S.A. (until 1997) and Japan (until 1999).…”

Blue-yellow deficiency in workers exposed to low concentrations of organic solvents

“…Acquired dyschromatopsia has been associated with exposure to mixtures of solvents, n-hexane, styrene, perchloroethylene, and carbon disul®de (Alieva et al 1985;Braun et al 1989;Campagna et al 1995;Cavalleri et al 1994;Chia et al 1994;Eguchi et al 1995;Fallas et al 1992;Mergler et al , 1988Mergler et al , 1990Raitta et al 1978Raitta et al , 1981. In contrast to the congenital form, acquired dyschromatopsia is not a clinical diagnosis but a symptom mostly caused by diseases of the retina and/or the optic nerve.…”