Retinopathy of Prematurity (ROP) is a condition effecting the retina in premature infants. As the retina develops, blood vessels grow within it. These vessels begin in the back of the eye, and grow forward. They typically finish forming at about the due date. When a child is born early, these vessels have not yet fully developed.
Following all infant deliveries, the oxygen level in the blood rises. In premature infants, the higher oxygen levels cause the forming retinal blood vessels to temporarily stop growing. In most infants these vessels eventually begin to grow again and develop normally. In a small number of infants, the vessels begin growing abnormally. This is called ROP. In severe cases of ROP, abnormal vessels grow into the vitreous cavity of the eye. These blood vessels are fragile and may bleed, causing vitreous hemorrhage. Scar tissue may form and pull on the retina causing a retinal detachment. The smaller and more premature the infant is, the more likely ROP is to occur.