VISUAL FUNCTIONS IN 6-YEAR-OLD CHILDREN IN RELATION TO LEAD AND MERCURY LEVELS

Within a larger comparative environmental health screening program in East and West Germany we investigated functions of the developing visu al system in field experiments in a total of 384 children living in th ree different areas. Visual functions were assessed neurophysiological ly by visual-evoked potentials (VEPs) and psychophysically by measurin g the contrast sensitivity (CS). Blood lead concentrations and urinary mercury levels were used as markers of environmental and/or amalgam-d erived exposure, respectively. The relationships among lead and mercur y concentrations and the neurophysiological and psychophysical outcome s were investigated by means of linear regression analysis. After adju sting for confounding effects, statistically significant lead-related changes were found only for some of the VEP interpeak latencies, while some of the CS values were significantly reduced with increasing merc ury concentrations. All other outcome variables were not significantly related to lead or mercury levels. It is concluded that even at blood lead levels in the range of 14 to 174 mu g/l and at very low urinary mercury levels subtle changes in visual system functions can be measur ed. (C) 1998 Elsevier Science Inc.