The aim of the present study is to evaluate the safety and efficacy of propranolol 0.2% eye drops in treating preterm newborns with a precocious stage of retinopathy of prematurity (ROP). Preterm newborns (gestational age 23-32 weeks) with a stage 1 ROP will receive propranolol 0.2% eye drops treatment until retinal vascularization will be completed, but no more than 90 days.