Assessment of visual functions following prenatal exposure to organic solvents

Prenatal exposure to organic solvents has been previously associated with increased risk of color vision deficits and reduced visual acuity in young children. These findings prompted us to evaluate visual functioning in solvent-exposed infants using more sensitive non-invasive visual evoked potential (VEP) techniques. VEP techniques are described in the context of an ongoing prospective longitudinal cohort study of infants exposed to organic solvents in utero. VEPs are recorded via three active electrodes fitted over the occipital cortex while infants view changing visual stimuli. The sweep VEP is used to assess contrast detection and visual acuity by presenting sinusoidal gratings that "sweep" across a range of contrasts and spatial frequencies. Transient VEPs are used to assess responses to equiluminant chromatic- and luminance-modulated sinusoidal gratings presented in pattern onset-offset format. A single case study is presented showing abnormal chromatic responses and reduced contrast sensitivity in a 2.5-year-old boy following prenatal exposure to perchloroethylene (PCE). These VEP techniques therefore appear promising for the clinical assessment of visual toxicity in pediatric populations.