Background
Environmental biotoxins, such as mould, are linked to neurological and visual dysfunction, including impaired visual contrast sensitivity (VCS). Testing VCS alterations is recommended as a biomarker for biotoxicity. This study compared four VCS tests in detecting VCS deficits in individuals with clinical signs of biotoxicity.
Methods
VCS was measured in 28 biotoxin-exposed individuals and 30 controls using four VCS tests: Shoemaker handheld chart, Online Contrast Sensitivity Test (OCSTTM), Clinic CSF App, and an Experimental VCS test. Neurotoxicity symptoms were assessed with the modified Q16 questionnaire, and pupil size was measured under standard lighting.
Results
Biotoxin-exposed participants had smaller pupil diameters (mean difference: 0.703 mm, p < 0.0001) and higher neurotoxicity scores (45.50 ± 13.0 vs. 22.00 ± 7.7). Contrast sensitivity was significantly reduced in exposed participants on digital VCS tests only. The Experimental VCS test demonstrated the highest diagnostic performance (100% sensitivity; 60-80% specificity), followed by OCSTTM and the Clinic CSF App. The Shoemaker handheld chart did not distinguish between groups.
Conclusion
These results highlight the effectiveness of digital VCS testing and symptom questionnaires as practical tools for detecting visual and neurological impairments in individuals with suspected biotoxin exposure.