Preliminary findings on the effects of occupational exposure to mercury vapor below safety levels on visual and neuropsychological functions.

OBJECTIVE To evaluate whether there are visual and neuropsychological decrements in workers with low exposure to Hg vapor. METHODS Visual fields, contrast sensitivity, color vision, and neuropsychological functions were measured in 10 workers (32.5 +/- 8.5 years) chronically exposed to Hg vapor (4.3 +/- 2.8 years; urinary Hg concentration 22.3 +/- 9.3 microg/g creatinine). RESULTS For the worst eyes, we found altered visual field thresholds, lower contrast sensitivity, and color discrimination compared with controls (P <0.05). There were no significant differences between Hg-exposed subjects and controls on neuropsychological tests. Nevertheless, duration of exposure was statistically correlated to verbal memory and depression scores. CONCLUSIONS Chronic exposure to Hg vapor at currently accepted safety levels was found to be associated with visual losses but not with neuropsychological dysfunctions in the sample of workers studied.