Retinopathy of prematurity (ROP) is an abnormal growth of the blood vessels in the eye that occurs primarily in very premature infants. Eye development occurs normally in the womb; in infants born prematurely, however, the blood vessels must finish developing outside the protective environment of the uterus. Retinopathy of prematurity (also known as retrolental fibroplasia) is a leading cause of blindness and other vision impairments (myopia, strabismus, and amblyopia) in children, both in developed and developing countries.