Retinopathy of prematurity in infants of 24-30 weeks' gestational age.

Over the 10-year period from January 1, 1977 to December 31, 1986, 1114 infants with gestational ages of 24 to 30 completed weeks were cared for on a long-term basis in our nursery; 757 (68%) infants survived. As expected, both the mortality rate and the prevalence of stage-3 or stage-4 retinopathy of prematurity among survivors fell with increasing maturity at birth (P less than 0.0001). Adjusting for gestational age, and excluding infants with lethal malformations, the mortality rate decreased significantly (P = 0.018) over time by an estimated 11.5%; also the survival rate of infants with at least stage-3 retinopathy of prematurity increased significantly (P = 0.005) by an estimated 6.8%. In other words, for every 10 additional survivors over the decade, six survivors would have been expected to show at least stage-3 retinopathy of prematurity in either eye. Although the prevalence of advanced stages of retinopathy of prematurity increased in immature survivors, it was not in epidemic proportions; however, it was more likely to be related to the survival of the increasing numbers of at-risk immature infants who, in earlier times, would have died.