Retinopathy of prematurity in infants weighing less than 500 grams at birth enrolled in the early treatment for retinopathy of prematurity study.

Purpose: To describe patient characteristics, classification, and onset of prethreshold retinopathy of prematurity (ROP), and ocular findings at 6 months corrected age in infants with birth weights <500 g who were enrolled in the Early Treatment for Retinopathy of Prematurity (ETROP) Study.

Design: Multicenter randomized clinical trial.

Participants: Sixty-three infants with birth weights <500 g who developed ROP and were enrolled in the ETROP Study.