Purpose: To examine the prevalence of myopia and high myopia at 9 months corrected age in premature infants who participated in the multicenter randomized trial of Early Treatment for Retinopathy of Prematurity (ETROP). Design: Randomized, controlled clinical trial. Participants: Four hundred one infants with birth weights of <1251 g in whom prethreshold ROP developed in one or both eyes and who were determined to have a significant risk (<15%) of poor structural outcomes without treatment, based on the risk management for ROP program. Intervention: Infants with bilateral high-risk prethreshold ROP (n = 317) had 1 eye randomized to early treatment, and the fellow eye was managed conventionally. In asymmetric cases (n = 84), the eye with high-risk prethreshold ROP was randomized to early treatment or conventional management (control). Eyes randomized to early treatment at high-risk prethreshold ROP and eyes randomized to conventional management in which threshold ROP developed received peripheral retinal photocoagulation or cryotherapy. Conventionally managed eyes in which threshold ROP did not develop were observed. Cycloplegic retinoscopy data were obtained at 9 months corrected age from 321 eyes treated early and 307 eyes managed conventionally. Main Outcome Measures: Prevalence of myopic (spherical equivalent < 0.25 diopters [D]) and highly myopic (<5.00 D) eyes in each group. Results: The prevalence of myopia (64.5% vs. 69.4%; P = 0.06) and high myopia (25.5% vs. 28.3%; P = 0.20) was similar between eyes treated at high-risk prethreshold and high-risk prethreshold eyes managed conventionally. Among high-risk eyes managed conventionally, the prevalence of myopia (78.2% vs. 53.3%) and high myopia (37.6% vs. 11.2%) was higher when threshold ROP developed than when regression without treatment occurred. Among eyes treated at high-risk prethreshold ROP, the prevalence of myopia (93.3% vs. 91.7% vs. 60.6%) and of high myopia (53.3% vs. 33.3% vs. 20.8%) was higher in eyes with abnormal angle of temporal retinal vessels or macular ectopia than in eyes with no retinal residua. This also held true for conventionally managed eyes. Conclusions: Early treatment at high-risk prethreshold did not place eyes at greater risk of myopia and high myopia than did conventional management of eyes with high-risk prethreshold ROP.