Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Retinopathy of Prematurity (ROP)


Leila M. Khazaeni

, MD, Loma Linda University School of Medicine

Reviewed/Revised Feb 2022 | Modified Sep 2022
Topic Resources

Retinopathy of prematurity is a disorder of premature infants in which the small blood vessels in the back of the eye (retina) grow abnormally.

The retina Structure and Function of the Eyes The structures and functions of the eyes are complex. Each eye constantly adjusts the amount of light it lets in, focuses on objects near and far, and produces continuous images that are instantly... read more is the transparent, light-sensitive structure at the back of the eye. The blood vessels in the retina start growing in a fetus at about 18 to 20 weeks of development in the uterus and continue growing until the fetus is full term. When infants are born very prematurely, the blood vessels supplying the retina may stop growing for a time. When growth resumes, it occurs in a disorganized fashion. During disorganized rapid growth, the small blood vessels may bleed. In the most severe cases, this process may ultimately result in detachment of the retina Detachment of the Retina Detachment of the retina is separation of the retina (the transparent, light-sensitive structure at the back of the eye) from the underlying layer to which it is attached. People notice a sudden... read more from the back of the eye and severe loss of vision.

Viewing the Retina

Viewing the Retina

Diagnosis of Retinopathy of Prematurity

  • Eye examinations

Retinopathy of prematurity does not cause symptoms, so diagnosis depends on careful examination The Eye Examination A person who has eye symptoms should be checked by a doctor. However, some eye disorders cause few or no symptoms in their early stages, so the eyes should be checked regularly (every 1 to 2... read more of the back of the eyes by an ophthalmologist (a medical doctor who specializes in the evaluation and treatment of all types of eye disorders). Routinely, therefore, an ophthalmologist examines the eyes of all premature newborns who weigh less than 3 pounds (about 1,500 grams) at birth or who were in the uterus for less then 30 weeks. Eye examinations are repeated every 1 to 3 weeks as needed, until growth of the blood vessels in the retina is complete.

Newborns with severe retinopathy must have eye examinations, at least yearly, for the rest of their life. If detected early, detachment of the retina can be treated with surgery in an attempt to avoid loss of vision in the affected eye.

Prognosis for Retinopathy of Prematurity

Retinopathy of prematurity is usually mild and resolves spontaneously. However, in a small percentage of affected infants weighing less than 2 pounds (about 1 kilogram) at birth, the disorder is severe and progresses to cause detachment of the retina and vision loss within 2 to 12 months after delivery.

Prevention of Retinopathy of Prematurity

When premature newborns need oxygen, oxygen levels are monitored carefully so that the lowest amount of oxygen necessary can be used. Oxygen levels can be indirectly monitored using a pulse oximeter Pulse oximetry Both arterial blood gas testing and pulse oximetry measure the amount of oxygen in the blood, which helps determine how well the lungs are functioning. Arterial blood gas tests are invasive... read more (an external sensor that measures the level of oxygen in the blood going through a finger or toe).

Treatment of Retinopathy of Prematurity

  • Laser photocoagulation

  • Bevacizumab

For very severe retinopathy of prematurity, laser photocoagulation treatment is done on the outermost portions of the retina. In this treatment, a laser beam is used to stop the abnormal growth of blood vessels and decrease the risk of detachment of the retina and loss of vision.

A drug called bevacizumab may also be injected to stop the abnormal growth of blood vessels in the retina.

If retinopathy of prematurity leads to a partial or complete detachment of the retina, sometimes surgery is done to reattach the retina and prevent further vision loss.

More Information

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

Drugs Mentioned In This Article

Generic Name Select Brand Names
Alymsys, Avastin, MVASI, Zirabev
quiz link

Test your knowledge

Take a Quiz!