Retinopathy of Prematurity (ROP)

Early signs of retinopathy of prematurity occur inside the eye, so they aren’t visible just by looking at your child. Only an ophthalmologist — a doctor who specializes in eye care — can detect ROP. They may do this by using special instruments to examine the retina or by reviewing images taken with specialized cameras.

The American Academy of Pediatrics and the American Academy of Ophthalmology have established ROP screening guidelines for all neonatal intensive care units, so that ROP can be identified during these routine exams and treated when necessary. In rare cases, a child with severe ROP may develop visible signs, such as nystagmus (abnormal eye movements) or leukocoria (a white pupil). These signs usually appear only after the disease has progressed significantly and often indicate retinal detachment. It's important to note that these symptoms can also occur in other eye conditions, even in full-term infants — so if your child shows any of these signs, an ophthalmologist should evaluate them right away.

Researchers are still working to understand the mechanism behind retinopathy of prematurity — that is, what causes the retinal vessels in many premature babies’ eyes stop growing, then begin growing abnormally. Studies led by ophthalmologist Lois Smith, MD, PhD, suggest that ROP might be caused by the early cutoff of supplements that babies receive from their mother in the womb, including omega 3 fatty acids, insulin-like growth factor I (IGF-I) and vascular endothelial growth factor (VEGF). However, it’s possible there are other factors are at play, and research is ongoing.

We do know that very premature birth and low birth weight are the top risk factors for development of retinopathy of prematurity. In general, the smaller and more premature the infant, the more likely they are to develop ROP, and the more likely they are to need treatment. It is also known that ROP is an oxygen-driven disease, so that need for prolonged oxygen supplementation, and multiple medical problems with poor weight gain are also risk factors.

Babies considered most at risk for ROP, and who therefore undergo screening examinations, have:

• A gestational age of 30 weeks or less, compared with 38 to 42 weeks for a full-term infant (“gestational age” means the amount of time since the baby was conceived)
• A birth weight of 1,500 grams (3.3 pounds) or less, which is 2,000 grams (about 4.4 pounds) less than for a typical full-term infant

Other possible risk factors for ROP include:

• Anemia 
• Infection
• Transfusions
• Breathing difficulties
• Heart disease
• Ethnicity (ROP occurs slightly more often in Caucasian children)

Guidelines for ROP screening (either by an ophthalmologist examining the retinas or reviewing retinal images) include:

• All infants with a birth weight of less than 1,500 grams (about 3.3 pounds) or a gestational age of 30 weeks or less should be screened by an ophthalmologist.
• Infants with a birth weight of 1,500 and 2,000 grams or a gestational age of more than 30 weeks should be screened if other health troubles put them at high risk for ROP.
• The first exam should occur four to nine weeks after birth, depending on how premature the baby is.
• If there are signs of ROP, the ophthalmologist will set follow-up exams to monitor the condition and determine when treatment is needed.
• Once the exam shows the retina is fully “vascularized” (its blood vessels have finished growing normally), the risk period for ROP is over, but a clinic visit may be recommended when your baby is six to 12 months old to monitor visual development.

The screening exam will take place at your child’s bedside in the NICU or, after discharge from the hospital, at the ophthalmologist’s office. Here’s what’s typically involved:

• Dilating eye drops, to enlarge the pupil (giving the doctor a bigger “window” into the eye)
• An eyelid speculum, which holds the eyelids open
• A scleral depressor, which helps move the eye into different positions so the entire retina can be checked
• An indirect ophthalmoscope, which has a special lens that sends a bright light into the eye, enabling the doctor to examine the retina
• High-resolution retinal imaging is increasingly used in some settings. Special cameras capture detailed digital photos of the retina, which help document findings and monitor your child’s eye health over time.

No parent wants his or her child to be unwell, and hearing that your baby is having trouble with something as vital as his eyes can be especially difficult to hear. But at Children's, we view the diagnosis as a starting point: With early detection of ROP, we can closely follow the progress of the disease to determine the right time to begin treatment, if needed, to get the best results for your baby's eyes.

If your child has mild retinopathy of prematurity (Stage 1 or 2), the abnormal retinal blood vessels usually heal on their own sometime in the first four months of life. But if the ROP worsens, they may need treatment.

The goal of treatment is to halt the abnormal blood vessel growth in the eyes and limit its harmful effects, like scarring or retinal detachment, and to allow normal retinal and blood vessel growth to resume. Some of the treatments are reviewed below, and specific risks and benefits for each procedure will be reviewed with you by your treating ophthalmologist.

Intravitreal injections

There are medications that can be injected into the eye to block VEGF (vascular endothelial growth factor), which is overly abundant in eyes affected by ROP. Several different medications have been used for this purpose, and ongoing research may expand treatment options in the future. One advantage of injection therapy is its relatively quick response, making it a preferred option for babies with rapidly progressing ROP. The procedure can be performed at the bedside using anesthetic eye drops for comfort.

Photocoagulation (laser therapy)

Laser photocoagulation is the standard treatment for ROP, particularly if there is not rapid progression or if the ROP is in zone II. The treatment takes longer and requires that the baby be comfortable and not move around, so usually sedation in the NICU or general anesthesia in the operating room is used. The ophthalmologist uses a laser mounted on the indirect ophthalmoscope to make tiny “burns” in the periphery of the retina, to prevent further growth of abnormal blood vessels.

Your child’s doctor will schedule follow-up exams—usually every one to two weeks at first—to monitor how the eyes are responding to treatment. If the ROP continues to progress, additional treatments may be needed, such as more laser therapy, further injections, or, in some cases, eye surgery.

Cryopexy (cryotherapy)

Cryotherapy is treatment that uses a probe on the outside of the eye to freeze parts of the peripheral retina. While cryotherapy was the main treatment used several decades ago, it's largely been replaced by laser therapy or injections, and is typically only used in special circumstances.

Eye surgery

If your child's retina becomes partly or completely detached (stage 4 or 5), your doctor may refer him to a retinal surgeon for treatment, usually scleral buckling or vitrectomy.

• Scleral bucklinginvolves placing a silicone band around the eye and tightening it until the retina is close enough to the wall to reattach itself. The band, called a scleral buckle, can be left in place as long as necessary to protect the eye from experiencing re-detachment, but is often released or removed in babies to allow for eye growth.
• Vitrectomy involves removing the vitreous (the gel-like substance that fills the back of the eye) and replacing it with saline solution or oil. During vitrectomy the scar tissue that causes traction on the retina can then be peeled back or cut away, allowing the retina to flatten back down against the wall of the eye.

At Children’s, experts in neonatal care and eye health team up to care for hundreds of infants with ROP each year. Our pediatric ophthalmologists work regularly with attending physicians in the Neonatal Intensive Care Unit (NICU) to screen babies for ROP and treat them when necessary. This strong partnership is a signature of the Children’s approach to safeguarding your child’s overall health.

In addition to offering the most up-to-date technology in detecting and treating ROP, we are also focusing on the future. Our physician-researchers are helping to identify which babies are at greatest risk for developing ROP, for example, and searching for ways to head off vision damage before it can start. They’re also examining the safety and effectiveness of promising new treatments that may change the way we treat ROP in the future.

You and your family are key players in your child’s medical care. It’s important that you share your observations and ideas with your child’s health care provider and that you understand your provider’s recommendations.

If your child is diagnosed with ROP, you probably already have some ideas and questions on your mind. But during the appointment, it can be easy to forget the questions you wanted to ask. It’s often helpful to jot them down ahead of time so that you can leave the appointment feeling that you have the information you need.

Some of the questions you may want to ask include:

• How severe is my child’s ROP?
• Will he require medical treatment?
• What is the treatment success rate?
• Does the treatment have any complications?
• What is the long-term outlook for my child?
• How frequently do I need to bring him in for follow-ups?

We understand that you may have a lot of questions when your child is diagnosed with retinopathy of prematurity. Is it dangerous? Will it affect my child long term? What do we do next? We've tried to provide some answers to those questions here, and our experts can help explain your child's condition more fully. If you have additional questions while your child is being treated at Boston Children's Hospital, we may be able to put you in touch with other Children's families who have dealt with ROP.

Children's also has several resources designed to give your family comfort, support and guidance:

• Children's Center for Families is dedicated to helping families locate the information and resources they need to better understand their child's particular condition and take part in their care. All patients, families and health professionals are welcome to use the Center's services at no extra cost. The center is open Monday through Friday from 8 am to 7 pm, and on Saturdays from 9 am to 1 pm. Please call 617-355-6279 for more information.
• You can learn more about topics in neonatal intensive care at a monthly drop-in group for local NICU parents hosted at Brigham and Women's Hospital, located near Children's in the Longwood Medical Area. The interactive forum features speakers—including Children's nurses and physicians—presenting information on a particular NICU topic.

There are a number of outside groups that provide additional help for families facing retinopathy of prematurity. Two to try:

• Pediatric Retinal Research foundation, a group started in 1990 by physicians and volunteers as ROPARD (Retinopathy of Prematurity and Related Diseases) continues to fund research to understand, treat and prevent retinopathy of prematurity and related retinal diseases. Their website includes tips and recommendations for parents of children who have suffered ROP-related vision loss and provides links to educational and supportive resources.
• National Eye Institute, which is overseen by the National Institutes of Health. The NEI conducts and supports research on eye diseases and vision disorders. It offers a searchable database of clinical studies, as well as a number of free publications written for vision patients and their families.

Q: Do all babies born prematurely get ROP?
A: No. ROP is most common in babies born very prematurely — for example, at 26 weeks or earlier — and much less common in those born closer to term, such as after 29 weeks. Even among babies who are screened and do develop ROP, about 90 percent of cases resolve on their own without the need for treatment.

Q: How common is severe ROP?
A: Of the approximately 14,000 premature babies diagnosed with ROP each year in the U.S., about 1,100 to 1,500 (roughly 10%) develop a form severe enough to require treatment. Around 400 to 600 infants become legally blind from ROP annually. In fact, ROP accounts for about 30 percent of cases of legal blindness in young children.

Q: Can ROP get better or heal on its own?
A: Yes. This is called regression of the disease and is common in mild cases (Stages 1 and 2). Regression can also occur in more severe cases, though there may still be retinal scarring that requires close monitoring over time.

Q: Does ROP always happen in both eyes?
A: Yes and no. ROP typically affects both eyes, but the severity can differ. In some cases, one eye may be more affected than the other, and treatment may only be needed for that eye.

Q: Does a diagnosis of ROP mean my baby has to stay in the hospital longer?
A: ROP screening doesn’t begin until a premature infant is four to nine weeks old, which means your baby might even be discharged from the NICU before he’s due for his first screening exam. If he’s diagnosed with ROP while still in the NICU, though, you’ll likely be able to take him home on schedule. Your doctors will watch how his ROP progresses—and decide when to treat it—through follow-up exams.

Q: How is ROP treated?
A: Injections of medication into the eye or laser therapy to the eye can help reverse the abnormal growth of blood vessels; in the most severe stages of ROP, eye surgery may be needed.

Q: What are the possible complications of ROP?
A: While most ROP is mild and resolves by itself, up to 10 percent of infants with retinopathy of prematurity will need treatment. Not all eyes respond to treatment though. If the ROP continues to worsen it can cause such complications as: •

• Scarring, dragging, or detachment of the retina
• Bleeding inside the eye
• Cataract
• Low vision or blindness

Premature children overall, and particularly children with more severe ROP, are at higher risk of developing certain eye problems later in life, such as myopia (nearsightedness), strabismus (misaligned eyes), and amblyopia (lazy eye). Children who require treatment for ROP will need lifelong follow up, with at least annual eye examinations.