Cumulative exposure to styrene and visual functions

Am J Ind Med. 2001 Apr;39(4):351-60. doi: 10.1002/ajim.1025.


Background: Results from a 1990-1992 longitudinal study of several reinforced plastics plants showed that for those workers whose styrene exposure had decreased, color vision (CV) improved; while near visual contrast sensitivity (CS) was poorer.

Methods: In 1999, we retested these visual functions in 18 workers with good visual acuity. A cumulative exposure index (CEI), corrected for respirator use, was calculated for each worker.

Results: Intra-individual comparison of mandelic acid (MA) showed a significant decrease over time (Friedman; P = 0.015), but current values were not related to CEI. For CV, no significant difference was observed between 1992 and 1999; present results were not related to MA or CEI. The CS profile decreased over time, with significant differences at 3 cpd (Friedman; P < 0.05). CS did not vary with MA levels, but was significantly depressed at the intermediate frequencies among those in the upper CEIH category (Kruskal-Wallis; P < 0.05).

Conclusions: These findings suggest that CS loss increases with long-term cumulative exposure, reflecting chronic damage to the neuro-optic pathways.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Analysis of Variance
  • Biomarkers / urine
  • Color Vision Defects / chemically induced
  • Color Vision Defects / urine
  • Contrast Sensitivity / drug effects
  • Contrast Sensitivity / physiology
  • Humans
  • Male
  • Mandelic Acids / urine
  • Middle Aged
  • Occupational Diseases / chemically induced*
  • Occupational Diseases / urine
  • Occupational Exposure / adverse effects*
  • Plastics
  • Styrene / adverse effects*
  • Surveys and Questionnaires
  • Time Factors
  • Vision Disorders / chemically induced*
  • Vision Disorders / urine


  • Biomarkers
  • Mandelic Acids
  • Plastics
  • Styrene