Colour vision and light sensitivity in tunnel workers previously exposed to acrylamide and N-methylolacrylamide containing grouting agents

Objectives The aim of the study was to examine possible persisting visual system effects in tunnel workers previously exposed to acrylamide and N-methylolacrylamide during grouting work. Material and methods Visual field light sensitivity threshold and colour vision has been examined among 44 tunnel workers 2–10 years after exposure to acrylamide and N-methylolacrylamide containing grouting agents. Forty-four tunnel workers not involved in grouting operations served as control group. Information on exposure and background variables was obtained for all participants from a questionnaire. Visual light sensitivity threshold was measured using Humphrey Visual Field Static Perimeter 740, program 30-2 Fastpack, with red stimuli on white background, and colour vision, using Lanthony D-15 Desaturated Color test. Based on D-15d test results, colour confusion index (CCI), and a severity index (C-index) was calculated. Results The exposed group had a significantly higher threshold for detecting single stimuli in all parts of the inner 30° of the visual field compared to the control group. The foveal threshold group difference was 1.4 dB (p = 0.002) (mean value, both eyes). On the Lanthony 15 Hue Desaturated test, the exposed subjects made more errors in sorting blue colours, and a statistically significant increase in C-index was observed. Surrogate measures...