 |
home < basic services < children's vision |
 |
 |
 Topics on this page include: |
| What is retinopathy of prematurity? | Cause | Effects | Treatment | Prognosis |
What is retinopathy of prematurity?
Retinopathy of prematurity is the most common cause of blindness in children. The retina, which lines the internal back surface of the eye, could be compared to film in a camera. It is responsible for capturing the visual images that are sent to the brain.
The retina, like other tissues in the body, has to have a blood supply. The development of the blood supply for the retina normally starts at about sixteen weeks into a pregnancy and is completed by thirty-six weeks. The blood vessels that supply the peripheral or outside portions of the retina are among the last parts of the eye to develop before birth. In fact, if the baby is born prematurely, those vessels may still be developing and may not have reached the outside edges of the retina. After the baby is born, the normal growth of these blood vessels stops, and abnormal blood vessels start to grow on and in front of the retina.
Depending on the severity of the problem, these abnormal blood vessels can damage the retina. The blood vessels grow in the wrong place, causing disturbances in the blood drainage pattern. If the blood vessels leak, scarring can occur. As the scars shrink, they can pull on the retina and cause it to detach.
The primary cause of retinopathy of prematurity is premature birth. The condition is usually found in children with very low birth weight (less than 1,500 grams or about three pounds), those who are born very early, or who have to have hi
gh doses of oxygen for a long period of time during the first weeks of life. Retinopathy of prematurity is most common in babies who weigh less than 1,250 grams and have a gestational age of less than twenty-eight weeks.
It is thought that lack of oxygen in parts of the retina which haven't developed blood vessels causes the release of chemicals that promote the growth of new abnormal blood vessels. Large amounts of oxygen may be toxic to the developing blood vessels and cause them to be abnormal. Other contributing factors include elevated blood carbon dioxide levels, anemia, blood transfusions, intraventricular hemorrhage, respiratory distress syndrome, chronic hypoxia in utero, multiple spells of apnea or bradycardia, mechanical ventilation, and seizures.
Milder forms of retinopathy of prematurity may go away spontaneously. More severe forms can result in blindness.
In severe cases of retinopathy of prematurity, the growth of abnormal vessels can be stopped by treating them with a laser or by freezing them. Sometimes when the disease has reached a certain stage, the decision is made to freeze parts of the retina that haven't yet developed blood vessels. This destroys the retina and removes the stimulus for abnormal vessels to grow.
The prognosis of the disease is dependent on the baby's birth weight and gestational age. Most cases of retinopathy of prematurity are resolved with very little damage. Five percent of premature infants will have some scarring and 1.2 percent will become blind.
Babies who have retinopathy of prematurity also have an increased risk of retinal detachment, cataracts, glaucoma, strabismus, amblyopia, and myopia.