What is Retinopathy of Prematurity?
Retinopathy of Prematurity (ROP) is a serious eye disease that can happen in very premature infants. The retina is the light sensitive inner layer of tissue on the inside of the eye which acts like the film of the camera. Normal retinal development involves the growth of blood vessels starting from the back of the eye and proceeding across the retina toward the front of the eye. This process is normally complete at about 40 weeks when the infant should have been born full term. For babies born after the 32 week point of pregnancy, retinal development will typically proceed normally.
Babies born at 31 weeks or earlier, or with a birth weight of 1250 grams or less, are particularly at risk for ROP. An arrest of normal retinal vasculature development can happen and lead to the formation of abnormal blood vessels at the edge of the undeveloped retina. These abnormal vessels can cause the formation of scar tissue which can detach the retina and leave the eye blind. Most of the babies that develop ROP have very mild disease that will resolve on its own.
What are the risk factors for severe ROP?
A number of risk factors have been identified for the development of severe ROP, the most important of which are early gestational age at birth, lower birth weights, and high supplemental oxygen exposure. Great strides have been made in recent years in balancing the oxygen exposure in premature infants to minimize the risk of ROP yet allow them what they need for overall health and survival. Other associated risk factors for ROP which are being investigated include respiratory distress (breathing difficulties), poor weight gain, anemia, and overall health.
How are babies checked for ROP?
Babies who are at risk for ROP undergo screening eye exams by a trained pediatric ophthalmologist or retina specialist. This exam involves dilating the pupils with eye drops and then looking directly at the retina with an instrument called an indirect ophthalmoscope. An eyelid speculum holds the eyelids open and another instrument is used to position the eye. Anesthetic eye drops are often used to numb the surface of the eye and increase the baby's comfort during the exam. For eyes that are developing normally or have mild ROP, exams will usually take place every 2 weeks until development finishes normally. Eyes that have more worrisome disease will be evaluated more often to see if they will require treatment.
How is ROP treated?
For severe ROP with a high risk for retinal detachment, a laser treatment can be performed by the ophthalmologist to stop the disease progress. The laser is applied to the undeveloped peripheral retina in order to save the remaining developed retina. The laser treatment takes longer than screening exams and will usually be done under anesthesia or sedation. In most cases the laser treatment is successful and the ROP disease subsides. However, in a few severe cases the disease may progress to retinal detachment even despite a well done laser treatment.
Importance of long-term follow-up
The very premature infants are at risk for other eye issues later such as extreme refractive errors (need for eye glasses), even if they did not develop ROP. As a result, these infants are usually seen in again by your pediatric ophthalmologist at 6-12 months old for a complete eye exam to rule out any other problems.