Color vision impairment in workers exposed to mercury vapor

• Published in: Medycyna pracy 2011, Vol.62 (3), p.227-235
• Main Authors: Jedrejko, Marta, Skoczyńska, Anna
• Format: Article
• Language: Polish
• Subjects: Adult; Air Pollutants, Occupational - adverse effects; Air Pollutants, Occupational - urine; Case-Control Studies; Causality; Color Perception - drug effects; Color Perception Tests; Color Vision Defects - chemically induced; Color Vision Defects - diagnosis; Color Vision Defects - epidemiology; Environmental Monitoring - methods; Epidemiological Monitoring; Humans; Male; Mercury - adverse effects; Mercury - urine; Mercury Poisoning - epidemiology; Methylmercury Compounds - adverse effects; Methylmercury Compounds - urine; Middle Aged; Multivariate Analysis; Occupational Exposure - adverse effects; Occupational Exposure - analysis; Occupational Exposure - statistics & numerical data; Poland - epidemiology; Spectrophotometry, Atomic - methods; Vision Screening - methods; Visual Acuity - drug effects
• ISSN: 0465-5893

Acquired reversible dyschromatopsia has been associated with occupational exposure to mercury vapor. Early-detected impairments in color discrimination precede adverse permanent effects of mercury, so they may help to monitor the health of the exposed workers. The aim of this study was to evaluate the color discrimination ability in this group of workers, using Lanthony D-15d test. Employed in a chloralkali plant, 27 male workers exposed to mercury vapor and 27 healthy white-collar workers (control group) were qualified for the study. To assess color discrimination, the Lanthony 15-Hue desaturated test (Lanthony D-15) was used. In order to investigate quantitative and qualitative results, the Lanthony D-15d scoring software was performed. Urinary mercury was determined using flameless atomic absorption spectrometry. In the workers exposed to mercury vapor, urine mercury concentration was 117.4 +/- 62.6 microg/g creatinine on average compared with 0.279 +/- 0.224 mg/g creatinine in the control group (p < 0.0001). In 18 exposed persons (66.7%), the results of the Lanthony D-15d test showed qualitative changes, which are borderline corresponding to the early stage of developing dyschromatopsia type III. The quantitative analysis of the test findings indicated a significantly higher value of the Color Confusion Index (CCI) in the right eye in the exposed group compared to the control group (p = 0.01), with no significant difference in the CCI in the left eye. In the exposed group, the CCI in the right eye was significantly higher than the CCI in the left eye (p = 0.0005). There was neither correlation between CCI and the level of urinary mercury, nor between CCI and duration of exposure. The results showed that the Lanthony D-15d test is useful in the detection of early toxic effects in the eyesight of the workers exposed to mercury vapor. The observed color vision impairments are borderline corresponding to the early stage of developing dyschromatopsia type III.