Assessment of visual contrast sensitivity in biotoxin-exposed individuals using four testing methods

Area of Science:

• Environmental Health
• Neuroscience
• Ophthalmology

Background:

• Environmental biotoxins, like mould, are associated with neurological and visual impairments.
• Impaired visual contrast sensitivity (VCS) is a potential biomarker for biotoxicity.
• This study evaluated VCS tests for detecting deficits in individuals exposed to biotoxins.

Purpose of the Study:

• To compare the efficacy of four different VCS tests in identifying visual deficits in individuals with suspected biotoxin exposure.
• To assess the utility of VCS testing as a biomarker for environmental biotoxin exposure.
• To correlate VCS deficits with neurotoxicity symptoms and pupil size.

Main Methods:

• Twenty-eight biotoxin-exposed individuals and 30 controls underwent four VCS tests: Shoemaker handheld chart, Online Contrast Sensitivity Test (OCST™), Clinic CSF App, and an Experimental VCS test.
• Neurotoxicity symptoms were evaluated using the modified Q16 questionnaire.
• Pupil size was measured under standard lighting conditions.

Main Results:

• Biotoxin-exposed participants exhibited significantly smaller pupil diameters and higher neurotoxicity scores compared to controls.
• Reduced contrast sensitivity was observed in exposed individuals exclusively on digital VCS tests.
• The Experimental VCS test showed the highest diagnostic performance (100% sensitivity), followed by OCST™ and Clinic CSF App; the Shoemaker chart was ineffective.

Conclusions:

• Digital VCS testing, alongside symptom questionnaires, serves as a practical and effective method for detecting visual and neurological impairments in suspected biotoxin exposure cases.
• These findings underscore the importance of utilizing advanced diagnostic tools for environmental health assessments.