Color vision and occupational toluene exposure

We examined the relationship between acquired color vision loss and exposure to toluene and total hydrocarbons among 125 male workers. Seventy-two toluene-exposed printers were compared with 34 workers from the same photogravure plant with ambient background exposure, and with 19 workers from a bookbinding plant located in the same town (nonexposed). Environmental mean toluene exposure level at workstation was estimated from individual 8-h sampling. Historic exposure data from the last 30 years were used to construct two cumulative exposure indices, one for toluene and one for total hydrocarbons. Airborne toluene levels were overall lower than the current Threshold Limit Value (TLV) of 50 ppm. Color vision was assessed by the Lanthony D-15 desaturated panel. Color vision loss was quantitatively established by the Color Confusion Index (CCI) and classified by type of acquired dyschromatopsia according to Verriest's classification. CCI was positively related to current airborne toluene levels, and cumulative exposure indices for toluene and total hydrocarbons (.18 less than or equal to r less than or equal to .35). Odds ratios of acquired dyschromatopsia were significant for current airborne toluene, toluene, and total hydrocarbon past exposure (1.27 [1.02-1.58], 1.21 [1.04-1.39], 1.15 [1.02-1.31], respectively). In conclusion, this study suggests that the Lanthony D-15 desaturated panel detects early neurotoxic effects among workers exposed to toluene. (C) 2001 Elsevier Science Inc. All rights reserved.