This disorder is sometimes called retrolental fibroplasia. The exact mechanism of ROP is not fully understood. The retina is the thin layer of light-sensitive nerve fibers and cells that covers the inside and back of the eye. The blood vessels of the retina are not completely developed until the baby reaches full term. When a baby is born prematurely, these developing blood vessels are vulnerable to changes in oxygen levels.
Premature babies are more likely to have breathing problems that can cause low oxygen in the blood.
They are also more likely to need oxygen therapy. It is thought that too much oxygen or lowered oxygen levels can lead to the growth of abnormal blood vessels, or damage and scarring of existing blood vessels in the retina. The scarring and bleeding can lead to retinal scarring or detachment from the back of the eye, resulting in vision loss. There are four stages of ROP, from a mild Stage 1 to severe Stage 4 when the retina detaches in the eye. Fortunately, about 90 percent of babies with Stage 1 and 2 ROP show improvement without treatment.