Prognostic factors in the natural course of retinopathy of prematurity. The Cryotherapy for Retinopathy of Prematurity Cooperative Group

Abstract

Background: There exists no reliable information that allows the ophthalmologist to predict with any degree of certainty a particular infant's chances of requiring surgical treatment for retinopathy of prematurity (ROP) or of reaching an unfavorable outcome on the basis of the retinal findings at the time of the nursery examination.

Methods: In the Multicenter Trial of Cryotherapy for Retinopathy of Prematurity (CRYO-ROP), 4099 infants weighing less than 1251 g at birth underwent eye examinations that began at 4 to 6 weeks after birth and subsequently continued at 2-week intervals. Independent variables in the population were studied using multiple logistic regressions.

Results: An increased risk of reaching threshold ROP was found associated with lower birth weights, younger gestational age, white race, multiple birth, and being born outside a study center nursery. For infants who developed ROP (66%), corresponding probabilities are presented for developing severe ("threshold") ROP or of having an unfavorable macular outcome. The risk of an unfavorable macular outcome was increased with zone 1 ROP, "plus" disease, the severity of the stage, and the amount of circumferential involvement. A higher risk also was associated with a rapid rate of progression of ROP to prethreshold disease but not with the postconceptional age at which ROP was first noted.

Conclusion: The findings indicate that the ocular characteristics of ROP, along with some easily identifiable and available basic systemic and demographic information about an infant, can assist the ophthalmologist in understanding variations in an individual baby's chance for a good or poor macular outcome.