Abstract
Aim:
Exposure to Perchloroethylene (PERC), a solvent used in dry-cleaning, is associated with neurotoxicity and changes in colour vision (CV) and contrast sensitivity (CS). However, PERCs' impact on other aspects of visual function (VF) such as chromatic contrast sensitivity (CCS), glass pattern detection (GPP), visual search (VS), and global motion sensitivity (GMS) remains unclear. This study compared VF and neurotoxicity in two populations at risk, dry-cleaners (cases) from Colombia and Australia. Control groups of people with community levels of exposure to PERC were also assessed.
Methods:
A case-control study of VF in people who are working in the dry-cleaning industry for at least 1 year (n = 40 Colombia; n= 34 Australia) with controls (n = 35 each site). VF measures assessed were CSF, CCS, the FM Hue 100 test, VS, GPP, and GMS. Neurotoxic symptoms were assessed using the Q16 modified version questionnaire.
Results:
Cases had poorer CCS, hue discrimination, GPP, GMS, and higher Q16 scores than controls (p < .05). There was no effect of country. CS function was poorer than controls (p < .05) for spatial frequencies≥0.50 cpd for Australian cases but for ≥1.0 cpd for Colombian cases. There were no significant differences between cases and controls for serial and parallel VS.
Conclusion:
Our CSF and CV findings indicate that the CS deficit extends to lower spatial frequencies. Furthermore we report a reduction in the detection of form, motion, and CCS. These deficits were associated with neurotoxic symptoms. Because VS was unaffected, it suggests that PERC affects lower order visual functions more severely than higher level cognition.