Retinopathy of prematurity (ROP), as the name suggests, can affect the eyes of infants who have been born early (preterm). The more preterm the baby, the greater the risk of ROP: ROP is unusual in babies who are only 3-4 weeks premature. Other factors which increase the risk of ROP are poorly controlled oxygen, infection, and failure to gain weight after birth, which means that preterm infants who receive suboptimal care from immediately after birth are the more likely to be affected.
Preterm infants are born with immature organs, including the light sensitive layer inside the eye, the retina, and the blood vessels which supply it. In ROP the immature blood vessels first stop growing normally, and then grow abnormally. The abnormal blood vessels can leak, and pull the retina away from the back of the eye (retinal detachment). Both eyes are usually equally affected.
Preterm babies are not born with ROP as it starts to develop a few weeks after birth.
Several different stages of ROP are described: some babies only develop the milder stages which get better without treatment. Other babies develop more severe stages which can progress rapidly to retinal detachment. Once the retina becomes detached, little can be done to restore vision, and the child becomes blind for the rest of their life.