Retinopathy of prematurity (ROP) is a disorder of the blood vessels of the retina (the light-sensitive part of the eye). ROP is most common in premature babies. Generally, the more premature the baby and the lower the birth weight, the greater the risk for developing ROP. This disorder has in the past been 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, the blood vessels may not have fully developed. They may have 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 five stages of ROP, from a mild Stage 1 to severe Stage 5 in which the retina detaches in the eye. Babies with Stage 1 and 2 ROP are called prethreshold, and those with Stages 3 through 5 are called threshold. About 90 percent of babies with Stage 1 and 2 ROP show improvement without treatment. However, about half of babies with Stage 3 and most of those with Stage 4 may develop serious eye damage. Each year, approximately 400 to 600 children are blinded by ROP.
In 2012, the American Academy of Pediatrics revised guidelines for a screening program to identify babies at risk for ROP. These guidelines include the following:
All infants with a birth weight of less than or equal to 1500 g or gestational age of 30 weeks or less should have retinal screening examinations.
Infants with birth weights between 1500 and 2000 g or gestational age of more than 30 weeks and are considered at a high risk should have retinal screening examinations.
Retinal examinations in preterm infants should be performed by an ophthalmologist experienced in identifying retinal changes of ROP.
Timing of acute-phase ROP screening should be determined using the infant's chronological age and gestational age at birth.
Follow-up examinations should be recommended by the examining ophthalmologist on the basis of retinal findings.
Early diagnosis of damage is important in the treatment of ROP. Babies who develop severe ROP may benefit from a treatment called cryotherapy that uses freezing to stop further damage from occurring. Another treatment uses laser photocoagulation to create small burns and scar tissue. These scars seal the borders of the retina helping prevent detachment. Other treatments for the most severe cases of ROP are a scleral buckle and vitrectomy. A scleral buckle is a silicone band placed around the eye to keep the vitreous fluid in the eye from pulling on the scar tissue. This allows the retina to stay flattened. Vitrectomy is a procedure to remove and replace the vitreous fluid, so that the scar tissue can be repaired. Surgical treatment may be used if the retina detaches.
Preventing premature births is the key to preventing ROP. However, research is ongoing to find ways to treat this and other problems of premature babies.