ASSESSMENT OF COLOR-VISION IMPAIRMENT IN MALE WORKERS EXPOSED TO TOLUENE GENERALLY ABOVE OCCUPATIONAL EXPOSURE LIMITS

We investigated colour vision impairment in 45 male workers occupation ally exposed to toluene (mean value of toluene concentration in ambien t air = 119.96 ppm) and in 53 controls. Colour vision was evaluated by Lanthony-D-15 desaturated test and expressed as Age and Alcohol Intak e Adjusted Colour Confusion Score (AACDS) or types of dyschromatopsia. Exposure was evaluated by measurement of toluene concentration in amb ient air and blood, and hippuric acid and orthocresol determined in ur ine after the workshift. A statistically significant higher AACDS valu e was established in the exposed subjects compared to the controls (p < 0.0001). There was no significant difference between AACDS values on Wednesday morning compared to Monday morning. In the exposed group AA CDS significantly correlated with the concentration of toluene in ambi ent air, concentration of toluene in blood and the concentration of hi ppuric acid in urine after the workshift tall p < 0.0001). Dyschromato psias were detected in both groups, although no significant difference between groups was established. In the exposed group, concentration o f toluene in ambient air, alcohol intake and age explained 35.1%, conc entration of toluene in blood, age and alcohol intake explained 19.9%, and concentration of hippuric acid in urine and age explained 19.2% o f the variation in type ill dyschromatopsia. Concentration of toluene in ambient air and age explained 28.3% of the variation in total dysch romatopsia, and concentration of hippuric acid and age explained 13.8% . In the control group, age and alcohol intake explained 19.6% of the variation in type III dyschromatopsia. In exposed workers a significan t difference was found in the AACDS value compared to controls. Howeve r, no significant difference was found in the prevalence of colour vis ion loss in the yellow-blue and/or red-green axis. Based on the result s oi ti-is study the authors conclude that the effect oi toluene on co lour vision can be chronic and that the possible reparation period in colour vision impairment is longer than 64 hours.