Retinopathy of Prematurity in Preemies

Retinopathy of prematurity, also called ROP, is a disease that affects the retina of the eye. ROP affects the blood vessels on the retina in a preemie's eyes and is one of the leading causes of childhood blindness.

Overview

During pregnancy, the blood vessels in a baby's eyes begin to develop around 16 weeks gestation. By about the 34th week of pregnancy, the blood vessels in the eye are well developed enough that the retina has a good blood supply.

When babies are born early, the blood vessels on the retina are not fully developed. After birth, the vessels may begin to grow so quickly that their growth damages the retina. Retinopathy of prematurity (ROP) is the name for the improper growth of the blood vessels on the retina and the damage caused by that growth.

In most preemies who develop ROP, the growth of the retinal blood vessels will slow down on its own, and vision will develop normally. Some premature babies, though, develop severe ROP.

Stages

Retinopathy of prematurity is classified according to different stages. Higher stages of ROP are more severe, and more likely to cause blindness or long-term vision problems. Lower stages of ROP are less severe; most children with stage I and II ROP will improve without treatment and will have normal vision.

• Stage 1: Mildly abnormal growth of retinal vessels. Usually gets better without any treatment and has no long-term effects.
• Stage 2: Growth of retinal vessels is moderately abnormal. Usually gets better without any treatment and has no long-term effects.
• Stage 3: Growth of retinal vessels is severely abnormal. Infants with stage 3 ROP may require treatment for ROP and have a higher risk of long-term vision problems. Infants with plus disease, a sign that ROP is advancing quickly, usually require treatment at this stage.
• Stage 4: Partial retinal detachment. Usually requires treatment and may lead to long-term vision problems or blindness.
• Stage 5: Complete retinal detachment. Requires treatment and may lead to long-term vision problems or blindness.

Diagnosis

Retinopathy of prematurity is diagnosed during an eye exam. To prepare for the exam, eye drops are used to dilate the baby's pupils. During the exam, an ophthalmologist will look carefully at the retina to evaluate whether the vessels are growing appropriately and, if not, what part of the retina is showing signs of trouble.

Not all premature babies will need an exam to test for ROP. Hospitals vary in which babies are screened for ROP, but most babies born before 31 weeks gestation will have at least one exam to test for ROP. If the exam is inconclusive or the baby's eyes show signs of ROP, then follow-up exams will be scheduled periodically.

Treatment

Most cases of retinopathy of prematurity will get better on their own and require no treatment.

In stage 3 ROP and higher, treatment may be needed to stop the abnormal growth of blood vessels on the retina or to correct a retinal detachment. Types of treatment include cryotherapy, laser therapy, and retinal surgeries.

• Cryotherapy: Cryotherapy uses cold temperatures to freeze parts of the retina that are affected by ROP, which stops the overgrowth of unhealthy blood vessels in the eye.
• Laser therapy: Like cryotherapy, laser therapy is used to stop the overgrowth of unhealthy vessels on the retina. A laser is used to make small burns on the parts of the retina affected by ROP. Laser therapy usually has better results than cryotherapy and is used more often, but cryotherapy may still be used in certain cases. In order to preserve central vision, some peripheral vision may be lost with both cryotherapy and laser treatment.
• Retinal surgeries: In stage 4 and 5 retinopathy of prematurity, the retina has begun to detach or is fully detached from the eye. A partial retinal detachment may get better on its own or may require surgery. A completely detached retina almost always requires surgery.

Long Term Effects

Up to 90% of babies born before 31 weeks will develop some form of ROP. Most cases of ROP are mild and have no long-term consequences. Children who suffered from ROP as infants may be nearsighted, or may have strabismus or amblyopia.

In cases of severe ROP, total vision loss may occur. Hospitals are much better at diagnosing and treating ROP before it causes blindness, but severe cases of ROP may still cause vision loss.

Oxygen Use and ROP

Supplemental oxygen is often used with respiratory support to help keep a baby's blood oxygen saturation at healthy levels. Adults and term infants need to keep oxygen saturation in the high 90s to stay healthy, but premature babies are different.

When premature baby care first became technologically possible, doctors and nurses worked hard to keep preemies' oxygen saturation at what would be a healthy level for adults. After much study, it was discovered that babies whose oxygen saturation was kept high had a much greater risk of developing ROP. Doctors and nurses can safely wean oxygen levels to keep oxygen saturation as low as 83% in preemies, helping to prevent ROP.