A study of visual function in the premature infant.

Within the first week of life visual tracking and pattern differentiation were tested in 34 out of 47 premature infants born between 28--34 weeks of gestation. Positive results were achieved from 30 weeks onwards. Pattern differentiation was tested as soon as infants could be taken out of the incubator. Preference could be observed from 31 weeks post-conceptional age. Both functions showed comparable maturation to full-term controls by 34 weeks gestation.