The development of visual function in normal and neurologically abnormal preterm and fullterm infants.

Pattern preference for four different pairs of patterns, and visual acuity based on the ability to distinguish black and white stripes of different widths, were compared in neurologically normal and abnormal preterm infants at 36 and 40 weeks postmenstrual age and in normal and abnormal fullterm infants in the newborn period and again at four and six weeks of age. The study aimed to chart the maturation process of these visual functions in the neonatal period and to assess their predictive value in the neurologically abnormal infant. Part I of the study deals with the normal infant and Part II with the abnormal infant. In Part I, the maturation process for both visual functions in newborn preterm infants of increasing gestational age is compared with longitudinal assessment of postnatal maturation of these functions in preterm infants up to 40 weeks postmenstrual age. Up to 36 weeks postmenstrual age the functions were comparable in the maturing preterm infants and the newborn infants of comparable postmenstrual age, but at 40 weeks the preterm infants did less well than the fullterm newborn infants. In Part II, the abnormal fullterm infants demonstrated a significantly poorer pattern preference at the initial and subsequent examination. Visual acuity was significantly poorer at the initial examination but less marked at follow-up. The abnormal preterm infants showed poorer pattern preference and visual acuity at both 36 and 40 weeks postmenstrual age. Compared with neurologically abnormal infants without intraventricular haemorrhage (IVH), preterm infants with IVH showed no significant difference in pattern preference at 36 and 40 weeks, but a significant deficit in visual acuity.