Chronic occupational exposure to low levels of organic vapors can affect color vision and contrast sensitivity.

Abstract

This study evaluated the level of exposure to organic vapors in chromatic and achromatic vision of 38 male gas-station workers (average of 6.82 ± 5.62 years worked). The level of exposure was found by passive method with gas chromatography. Color vision was assessed by Lanthony desaturated D15 tests (D15d; Lanthony, 1978) the Cambridge Color Test (CCT; Mollon, & Reffin, 1989), and contrast sensitivity by sinusoidal gratings at frequencies 0.2, 0.5, 1, 2.0, 5, 10 and 16 cycles per degree (cpd). The highest average daily concentrations found in gasoline (168 ppm) were below the threshold limit values (300 ppm), yet gas-station workers had a higher color-confusion index (CCI) for D15d (p < .01), predominantly for blue/yellow (75%), larger ellipse areas in the CCT (p < .05), and lower sensitivity contrast for 5, 10, and 16 cpd (p < .01). Prolonged service time correlated with the areas A1 (ρ = 0.46; p < .01), A2 (ρ = 0.63; p < .01), and 5 cpd (ρ = – 0.36; p < .05). Gas-station attendants with 8–20 years of service had lower performances for the areas A1 and A2 (p < .0083) than those with less exposure (1–3 years of service). The results show that chronic exposure to organic vapors can reduce the chromatic and achromatic visual perception of luminance in gas-station workers with age, even at low levels, suggesting the inadequacy of tolerance levels used for gasoline. The also highlight the need for chronic systematic long-term monitoring, and not just daily.

Color Vision in the Gas Station Workers of Isfahan City: A Quantitative Analysis With the Farnsworth D15 Color Test

“…Visual dysfunction can indicate neural changes in the peripheral system. Since color vision deficiency is probably the result of damage to ocular structures, it is possible to diagnose color vision deficiency before patients are aware of functional damage [3].…”

“…The employees of gasoline stations are exposed to petroleum products in long work shifts, thus, they are exposed to vapors emanating from gasoline materials by breathing in air. These vapors are also absorbed by the eyes [3].…”

“…Oil-rich countries or oil-producing countries are among the most important target communities for these disorders. Besides, some research has been done on the effects of gasoline on visual functions, including color vision [3,4].…”