RETINOPATHY OF PREMATURITY (ROP) IN INFANTS: CAUSES, SYMPTOMS, AND TREATMENT

Medically Reviewed by Dr. Sony Sherpa (MBBS)

Retinopathy of Prematurity (ROP) is a congenital eye disorder that typically affects premature infants. It is one of the leading causes of vision loss in children worldwide, affecting an estimated 14,000 infants in the U.S. annually, with 90% having mild disease. 1,100-1,500 infants need medical treatment for severe ROP, and 400-600 infants become legally blind each year due to ROP.^[1]

This article delves into the causes, risk factors, stages, diagnosis, treatment options, and the latest advancements in ROP research.

What is Retinopathy of Prematurity?

Retinopathy of Prematurity (ROP) is a disorder that affects the structure and function of the retina, the tissue at the back of the eye that responds to light and is responsible for vision. It occurs in premature infants, usually those born before 31 weeks of gestation or weighing less than three pounds at birth.^[2]

In premature infants with ROP, the retina and its blood vessels do not fully develop, as the last stages of retinal development usually occur during the final weeks of pregnancy. Inadequate oxygen supply to the retina during this time can result in abnormal blood vessel growth, which may lead to scarring or detachment of the retina. If left untreated, ROP can lead to significant vision problems or blindness.

Causes of Retinopathy of Prematurity

It is not quite clear what causes ROP specifically. Experts believe that it relates to the level of oxygen in the infant's blood. Research indicates that the cause of retinopathy of prematurity (ROP) is related to the developing retina and exposure to oxygen therapy. In utero, the fetus and retina are in a low-oxygen environment, and growth follows high levels of vascular endothelial growth factor (VEGF). This allows for vascularization of the retina. Upon birth, the infant switches to an oxygen-rich environment. Premature infants often require oxygen therapy to help them breathe, and high levels of oxygen can damage the premature blood vessels in the retina. This damage can lead to abnormal blood vessel growth and scarring, which can cause vision problems.

In ordinary birth, the structures of the eye develop fully and continue to mature outside of the womb due to elevations of growth factors such as IGF-1. In a premature birth, the infant lacks growth factors and other nutrients that help the eye develop appropriately outside the womb^[3].

Other risk factors for ROP include:

• Low birth weight
• Multiple births
• Maternal conditions such as diabetes or high blood pressure
• Family history of ROP

Studies reveal that in infants with a birth weight under 1251g, every 100g increase in weight led to a 27% decrease in the odds of developing ROP and a 19% risk reduction for each additional week spent in utero.

Genetic testing has also shown that certain genetic variations may increase the risk of developing ROP.

Stages of Retinopathy of Prematurity

There are five stages of ROP, with stage 1 being the mildest presentation and stage 5 being the most severe form. The stages are based on the appearance of the retina and the extent of abnormal blood vessel growth.^[4]

1. In stage 1, there is mild abnormal blood vessel growth, and it does not affect vision.
2. In stage 2, the abnormal blood vessels begin to grow towards the retina's center without reaching it. In some cases, stage 2 ROP may regress and resolve independently without treatment.
3. In stage 3, the abnormal blood vessels continue to grow towards the retina's center, and the retina may become swollen or thickened. This is known as pre-plus disease. It is called plus disease if the swelling or thickening becomes more severe. Plus disease is a sign that the ROP is progressing and may require treatment.
4. In stage 4, the abnormal blood vessels have grown into the retina's center, causing it to detach from the back of the eye. This can cause extreme vision loss or blindness if not treated promptly.
5. In stage 5, the retina has completely detached, and the eye may appear white or cloudy. This stage constitutes a medical emergency and demands immediate treatment to rescue vision and prevent permanent loss.

Signs and Symptoms of Retinopathy of Prematurity

In the early stages, ROP may not cause any noticeable symptoms. During the later stages, the following signs and symptoms may present:

• Abnormal eye movements
• Crossed or wandering eyes
• White or cloudy appearance of the eye
• Poor vision or vision loss
• Redness or swelling of the eye
• Abnormal pupil size or shape

If your child is at risk for ROP, it is essential to have their eyes evaluated regularly to monitor for any signs of the disease and treat it early on.

Complications

If left untreated, ROP can lead to severe vision loss or blindness.

In addition, the disease can cause other complications, including:

• Strabismus (misaligned eyes)
• Amblyopia (lazy eye)
• Nystagmus (involuntary eye movements)
• Cataracts (clouding of the eye's lens)
• Glaucoma (increased pressure in the eye)
• Retinal detachment (separation of the retina from the back of the eye)

Diagnosis and Early Detection of ROP

Early detection of ROP is crucial for successful treatment and preventing vision loss. All premature infants should have a comprehensive eye exam by an ophthalmologist within the first few weeks of life. The exam will involve dilating the pupil with eye drops and using a special instrument to examine the retina.^[5]

If ROP is detected, the ophthalmologist will classify the stage and determine the appropriate treatment plan. Regular follow-up exams are necessary to follow disease progression and adjust the treatment plan if needed.

Treatment Options for Retinopathy of Prematurity

The treatment for ROP relies on the stage and severity of the condition. In some cases, the disease may resolve independently without any treatment. However, if treatment is necessary, several options are available.

Laser Treatment

Laser treatment, or photocoagulation, is the most common treatment for ROP. A specialist surgeon operates a laser to destroy the abnormally-formed blood vessels in the retina, preventing them from growing further. This treatment is usually done in the ophthalmologist's office and may require multiple sessions.

This treatment is successful in up to 90% of ROP cases.^[6]

Anti-VEGF Injections

Anti-VEGF (vascular endothelial growth factor) injections are a newer treatment option for ROP. These injections block abnormal blood vessels' growth in the retina. They are typically used in more severe cases of ROP and may be combined with laser treatment.

Vitrectomy

In some cases, ROP may lead to retinal detachment, which requires surgery to repair. A vitrectomy is a surgical procedure that concerns replacing the vitreous gel from the infant’s eye with a gas or oil bubble to help the retina reattach.^[7]

Scleral Buckle Procedure

Another surgical option for repairing a detached retina is a scleral buckle procedure. This procedure involves positioning a silicone band around the eye to secure the retina back into place.

Can Retinopathy of Prematurity Be Prevented?

While there is no guaranteed way to prevent ROP, there are steps that reduce the risk of developing the disease. These include:

• Prenatal care to reduce the risk of premature birth
• Avoiding exposure to cigarette smoke during pregnancy
• Prompt treatment of maternal conditions such as diabetes or high blood pressure
• Monitoring oxygen levels closely and adjusting as needed to prevent high levels of oxygen in the blood
• Limiting the use of oxygen therapy to only what is necessary for the infant's health

Living with ROP

For infants who have been diagnosed with ROP, regular follow-up exams and treatment may be necessary to monitor and manage the disease. In some cases, ROP may resolve independently without any long-term effects on vision. However, some children may experience vision loss or other complications that require ongoing care.

Latest Advancements in ROP Research

Researchers are continually working to improve our understanding of ROP and develop new treatments. Some of the latest advancements in ROP research include:

• Ultra-widefield Imaging: Ultra-widefield imaging devices allow for a much more comprehensive view of the retina than traditional tools. This enables earlier detection of subtle changes in the retina's periphery, which is crucial for early ROP diagnosis.^[8]
• Artificial Intelligence (AI): AI-powered algorithms are in development that analyze retinal images. The goal is to automatically identify signs of ROP, potentially aiding ROP screening programs and ensuring consistency in diagnosis.^[9]
• Genetic Testing: Genetic studies help researchers identify specific genes linked to an increased risk of ROP^[10]. This can lead to more targeted screening protocols and personalized treatment plans.
• Telemedicine Applications: In regions with limited access to specialized ophthalmologists, telemedicine allows high-quality retinal images to be captured and examined by experts elsewhere. This extends the reach of ROP screening to underserved communities.^[11]
• Stem Cell Therapy: Researchers are investigating the ability of mesenchymal stem cells to promote retinal blood vessel repair and reduce inflammation, which could potentially halt ROP progression or even reverse damage. While still in the early stages, this offers a promising avenue for future treatment.^[12]
• Cryotherapy: While laser therapy is now the primary treatment for ROP, cryotherapy continues to be studied for its potential in specific cases. Research focuses on refining the technique, minimizing side effects, and potentially expanding its use to areas with limited access to laser technology.^[13]

Conclusion

Retinopathy of Prematurity is an eye disorder primarily affecting premature infants that can lead to eye blindness if not treated promptly. Regular eye exams for premature infants are crucial for detecting and treating ROP early on. While there is no guaranteed way to prevent ROP, there are steps that can reduce the risk of developing the disease. With early detection and appropriate treatment, many infants with ROP can have successful outcomes.

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