Student Research: Jeffrey H. Ward

, , 1994
Faculty Advisor: Thomas M. Burbacher

The Effects of In-Utero Methanol Exposure on the Development of Visual Acuity in Infant Monkeys


Abstract

Use of fuel additives without documentation of safety, as in the case of lead, has resulted in enormous public health consequences. The proposal to add methanol to gasoline or design automobiles that use mathanol as a primary fuel will necessarily widen consumer exposure to this material. The health effects that may be associated with increased environmental exposure to methanol are not well documented at this time. This study provides the first data on the functional consequences on visual acuity of in-utero exposure to methanol in non human primate infants. Macaca fascicularis females were exposed to either 0 ppm, 200 ppm, 600 ppm, or 1800 ppm methanol in air for 2 hours/day 7 days/week prior to and during pregnancy. Infants were tested at 1, 4, 8, 12 and 16 weeks of age using black and white stripes of varying spatial frequencies (5 spatial frequencies/test). The method chosen for assessing infant vision was the two alternative forced-choice preferential looking paradigm. This method relies on the infant's tendency to preferentially fixate on black and white stripes versus a gray field. An observer, blind to the position of the stripes (left or right), indicates the stripes position based on the visual fixations of the infant. To obtain visual acuity thresholds, observer performance (% correct) versus strupe width was plotted and the stripe width associated with 75% correct response was calculated. Visual acuity was found to increase in a linear fashion, consistent with the results of previous developmental studies. The development of visual acuity for the methanol exposed offSpring