Retinopathy of prematurity. Diagnosis, severity, and natural history.

This article presents data gathered in a prospective clinical trial of constant monitoring of oxygen therapy on the diagnosis, severity (as coded by a severity index [SI]) and natural history of retinopathy of prematurity (ROP) in 214 surviving infants with birthweights less than or equal to 1300 g. ROP developed in 119 (55.6%) infants and, of these, cicatricial ROP developed in nine (7.6%). The disease was diagnosed at 8-9 weeks on the average in infants with birthweights less than 900 g and 4-5 weeks in infants 900 to 1300 g. Those infants in whom the disease regressed, ROP lasted approximately 15 weeks. The severity of the disease, as defined by the SI, was strongly correlated with the birthweight of the infant and weakly correlated with the total duration of oxygen therapy.