Visual acuity and contrast sensitivity measurements after experimental triethylamine exposures

Abstract

Objective: The objective was to define the dose-response for triethylamine (TEA) vapour-induced visual changes. Methods: Four core makers were exposed in a dynamically-controlled whole-body chamber to TEA for 4 h at the concentrations of 40.6, 6.5 and 3.0 mg/m3. Before and after the exposure binocular visual acuity and contrast sensitivity at 2.5% contrast were measured. The visual measurements were carried out with the use of optotype test charts (Precision Vision, Villa Park, Ill. USA). The outcome was determined as a change in the rows of the test chart. Results: Visual acuity decreased in three of the four subjects after 40.6 mg/m3 TEA exposure, and remained at the pre-exposure level after 6.5 and 3.0 mg/m3 exposures. Contrast sensitivity at 2.5% contrast decreased in the same three subjects after 40.6 and 6.5 mg/m3 TEA exposures but remained at the pre-exposure level in all subjects after the TEA exposure of 3.0 mg/m3. Conclusions: TEA exposure over 4 h at the concentration of 3.0 mg/m3 in air caused no changes in contrast sensitivity. A corresponding exposure at the concentration of 6.5 mg/m3 caused deterioration in contrast sensitivity in most subjects. Because the blurring of vision occurs within 4 h after the start of working with TEA the results can probably be applied for the setting of an 8 h occupational exposure limit. Moreover, the results are consistent with the current 4.1 mg/m3 ACGIH TLV.