Retinopathy of Prematurity

What is Retinopathy of Prematurity (ROP)?
Retinopathy of prematurity (ROP) is a potentially blinding condition that affects premature infants.
Each year about 600 infants in the US become legally blind from ROP.


Why does ROP occur?
ROP occurs when the retinal blood vessels develop abnormally. The retinal blood vessels begin to form at the optic nerve in the back of the eye and grow gradually toward the front of the eye. Growth is complete at 40 weeks, about the time a full-term baby is born. If a baby is born prematurely, before the vessel growth is complete, normal vessel growth may stop and abnormal vessels may grow. When a baby is born before complete development of the retinal vessels, the periphery of the retina may not get enough oxygen and nutrients. This part of the retina then sends out signals for new blood vessels to grow and these vessels grow abnormally. They lead to the growth of scar tissue, which contracts, pulls on the retina and causes it to detach from the back of the eye. This detachment can then lead to loss of vision.


Who is at Risk for developing ROP?
Infants with ROP usually weigh less than 1250 grams (2 ¾ pounds) and are born before 34 weeks of gestation. The smaller that baby is at birth, the more likely that baby is to develop ROP. Infants at risk of developing ROP should be screened in the NICU by a trained Ophthalmologist. These infants are followed until either they need treatment or the risk of visual loss subsides. Close follow up after discharge from the hospital may be necessary.


What are the Stages of ROP?
ROP is classified into five stages based on severity.


STAGE 1: Mildly abnormal blood vessel growth. Many will resolve spontaneously and not require treatment.


STAGE 2: Moderately abnormal blood vessel growth. Many will resolve spontaneously and not require treatment.


STAGE 3: Severely abnormal blood vessel growth. The abnormal vessels grow toward the center of the eye into the vitreous cavity. Some infants at this stage may not require treatment. Others will continue to progress, and develop a situation that raises the risk of retinal detachment. Treatment at this time is indicated.


STAGE 4: Partially detached retina, produced by traction from the scar tissue.


STAGE 5: Completely detached retina.


How is ROP Treated?
ROP in stages 1-3 is treated by laser or cryotherapy (freezing). Laser burns away the avascular or ischemic peripheral retina. This leads to the regression of the abnormal vessels. Not all infants respond

to treatment. In the absence of a response, the disease may progress and the retina detach. Once the retina is detached (stages 4-5), laser is no longer effective and surgery must be performed to try to re-attach the retina.


What can one with ROP expect?
While the visual prognosis for stages 1-3 is fairly good, the visual prognosis in stages 4-5 is poor. ROP infants are also at risk for developing nearsightedness, lazy eye, crossed eyes, retinal detachments, and glaucoma.

For more information about ROP, you may wish to visit/contact:


Association for ROP and Related Diseases


National Eye Institute (NEI)
Retinopathy of Prematurity (ROP) Resource Guide