1543 A NEW LOOK AT VISUAL AC0ITY IN PREMATURE INFANTS

Abstract

Visual acuity increases during the first year of life. It has been suggested that visual acuity increases in premature infants along the same post conceptual time scale (corrected age) as it does in full term infants. However, these findings have been obtained using methods that rely on observations of infant behavior. As a result, delayed visual acuity in preterm infants may reflect immaturity in motor and postural behaviors rather than in the visual pathway itself. We used a rapid computerized Visual Evoked Potentials (VEP's) system to assess the functional integrity of the visual cortex in term and preterm infants during the first year of life. We recorded VEP's to a graded series of bar patterns which allowed acuity measurements to be made in 10 sec presentations. Contrary to prior behavior studies, we found that visual cortex development in premature infants (born at 28 to 36 wk gestation) was significantly advanced compared with full term infants. Visual acuity (measured by VEP) in premature infants was significantly greater than the visual acuity measured in full term infants when compared on the basis of their post conceptual (corrected) age. Postnatal factors may play a significant role in the accelerated development of the visual cortex in premature infants.