The eyes of 177 very preterm (less than 33 weeks' gestation) infants, born between 1979 and 1982 and admitted to a neonatal intensive care unit, were examined as part of an ongoing follow-up study of neurodevelopmental outcome. Ocular pathology was diagnosed in 37 (21%) of the 177 infants: 14 (8%) had retinopathy of prematurity (ROP)--progressive in three--and nine (5%) infants had delayed visual maturation (DVM). The ocular pathology was permanent in 26 (15%) of the 177 infants. Refractive errors were the commonest problem and accounted for permanent sequelae in eight of the 14 infants with ROP and two of the nine with DVM. The presence or absence of ROP was related to a wide range of prospectively coded perinatal variables and to the results of routine neonatal ultrasound brain scans and neurodevelopmental follow-up assessments made in the first 18 months of life. As in previous studies, infants with ROP were of shorter gestation, lower birth weight, and required oxygen therapy for longer than unaffected infants, but the condition was only weakly associated with other indices of respiratory illness. In contrast, ROP was strongly associated with evidence of brain damage, often consistent with hypoxic ischaemic injury. We conclude that an underlying lesion in ROP may be hypoxic ischaemic damage to the retinal circulation.