Retinopathy of Prematurity (ROP)

What happens in retinopathy of prematurity

Blood vessels of the retina start growing from the center of the eye at about 16 weeks of pregnancy and reach the edges near full term. When a baby is born early, vessel growth stops partway. The outer retina without vessels becomes starved of oxygen as it matures and releases growth signals, especially VEGF (vascular endothelial growth factor). This can trigger abnormal, fragile vessels that grow into the gel of the eye. These vessels can bleed and form scar tissue that pulls on the retina and detaches it.

Risk factors

• Lower gestational age and birth weight, the strongest factors
• High or fluctuating oxygen levels, which is why neonatal units carefully target oxygen saturation
• Poor weight gain after birth
• Infections and sepsis, blood transfusions, and breathing problems such as bronchopulmonary dysplasia

Who gets ROP screening

US guidelines from pediatric and ophthalmology societies recommend screening for:

• Babies born at 30 weeks or less, or with a birth weight of 1,500 g (3.3 lb) or less
• Some babies between 1,500 and 2,000 g or born after 30 weeks with an unstable medical course

The first exam is usually at 31 weeks after conception or 4 weeks after birth, whichever comes later. Exams then repeat every 1 to 3 weeks until the retinal vessels have fully grown or ROP has clearly regressed. An eye specialist widens the pupils with drops and examines the retina with a light and lens, sometimes with retinal photography. Babies may be briefly uncomfortable but the exam is safe.

Retinopathy of prematurity stages

ROP is described by location (zone), severity (stage), extent and whether plus disease is present.

• Zones: Zone I is the center around the optic nerve, Zone II the middle ring and Zone III the outer edge. Disease in Zone I is the most dangerous.
• Plus disease: widened, twisted vessels at the back of the eye, a sign of active, severe disease that often needs treatment.
• Aggressive ROP (A-ROP): a rapidly progressing form in the tiniest babies that can skip the usual stages.

Most babies with stage 1 or 2 ROP recover without treatment.

Treatment

Treatment is recommended for type 1 ROP, a defined high-risk combination of zone, stage and plus disease, and should usually be given within 2 to 3 days of it being found.

• Laser photocoagulation: a laser treats the outer retina that lacks blood vessels, stopping the VEGF signal. It is highly effective and permanent but can reduce side vision and is linked to more nearsightedness.
• Anti-VEGF injections: medicines such as bevacizumab, ranibizumab or aflibercept are injected into the eye. They work quickly, are especially useful for Zone I disease and allow vessels to continue growing. ROP can return weeks to months later, so babies need longer follow-up, sometimes with laser later.
• Surgery: for stage 4 or 5, procedures such as vitrectomy or scleral buckling try to reattach the retina. Results are better in stage 4A than in stage 5.

Long-term effects and follow-up

Children who had ROP, even mild ROP that resolved, have a higher risk of:

• Myopia (nearsightedness), often high
• Strabismus (misaligned eyes)
• Amblyopia (lazy eye)
• Glaucoma and cataract
• Retinal detachment later in childhood or adulthood

Follow-up with a pediatric ophthalmologist usually starts within a few months of discharge and continues through childhood. Early glasses or patching protect vision development. Adults who had ROP should tell their eye doctor and seek urgent care for new floaters, flashes or a curtain over vision.

Outlook

Thanks to screening and timely treatment, most babies with ROP keep useful vision. Severe vision loss now mainly affects the most premature infants or babies who miss screening. Prevention focuses on careful oxygen management and good overall neonatal care.

Frequently asked questions

What causes retinopathy of prematurity?

ROP happens because retinal blood vessels have not finished growing when a baby is born early. The undeveloped retina releases growth signals such as VEGF that can drive abnormal vessel growth. Very early birth, low birth weight, oxygen fluctuations, infections and poor weight gain all raise the risk.

Does retinopathy of prematurity go away?

Most mild ROP, stages 1 and 2, regresses on its own as the eye matures, often by about 40 to 45 weeks after conception. Severe ROP needs treatment to prevent retinal detachment. Even after it resolves, children need regular eye exams because of higher risks of nearsightedness and crossed eyes.

Which babies need ROP screening?

In the US, babies born at 30 weeks of pregnancy or earlier, or weighing 1,500 g (3.3 lb) or less, are screened. Some larger or older babies with a complicated course are screened too. The first exam is usually 4 weeks after birth or at 31 weeks after conception, whichever is later.

Is laser or injection better for ROP?

Both work well. Laser is permanent and has long experience, but destroys peripheral retina and is linked to more nearsightedness. Anti-VEGF injections act fast and suit central (Zone I) disease, but ROP can recur, requiring longer monitoring. The eye specialist chooses based on disease location and severity.

Can ROP cause blindness?

Yes, if severe ROP leads to retinal detachment and is not treated in time. With modern screening and treatment, blindness has become uncommon. ROP remains a leading cause of childhood visual impairment worldwide, especially where neonatal care has improved survival but screening is limited.