Visual function in the preterm and fullterm newborn infant.

Visual function in the preterm newborn infant has been studied by the visual orientation (tracking) technique of the Brazelton neurobehavioural assessment, and by the pattern preference and fixation techniques of Frantz. Both these methods demonstrated the presence of discriminative visual function by 31 to 32 weeks gestation, which by 34 weeks reaches a maturity comparable to the pattern found in fullterm infants. Sequential studies at weekly intervals of preterm infants, ranging in gestation from 28 to 32 weeks, have shown a similar pattern of development of visual function to that of the newborn infant of equivalent postconceptional age. However, comparative studies of visual orientation and pattern preference in the same infants have not shown a close correlation. The assessment of visual function in the preterm newborn infant is a valuable milestone. Aberrations may reflect a dificit in visual function itself, a more broad-based deficit in neurological function, or possibly a response to a generalised illness.