Coats Disease

What is Coats disease?

Coats disease causes blood vessels in your child’s eye to develop incorrectly. Specifically, it affects blood vessels in their retina. Eventually, it makes the blood vessels swell and leak plasma into their retina. You might see it referred to as Coats’ syndrome or exudative retinitis.

The retina is the layer at the very back of your eyeball. It converts light that enters your eye into electrical signals your optic nerve sends to your brain, which creates the images you see.

Blood vessels are channels that carry blood throughout your body. They form a closed loop, like a circuit, that begins and ends at your heart.

Coats disease makes the tiny blood vessels in your child’s retina dilate (expand), twist and leak. The leak is usually small and takes time to cause symptoms you’ll notice — think about the difference between running over a nail and making your car’s tire lose air slowly and hitting a pothole and bursting it all at once.

Coats disease usually affects one eye (unilaterally), but it can develop in both eyes at the same time (bilateral Coats disease). It’s usually diagnosed in kids and teens but can develop at any age. It can make your child’s vision worse and lead to serious complications like a detached retina and blindness in their affected eye.

Talk to your healthcare provider or eye care specialist as soon as you notice any changes in your child’s eyes or vision.

What are Coats disease symptoms?

Your child might not have any symptoms of Coats disease, especially early on. If they do have symptoms, they might include:

• Worsening vision.
• Crossed eyes (strabismus).
• Eye pain.
• A white or silvery pupil (leukocoria).

Coats disease stages

Coats disease progresses (becomes more severe) in stages. They range from stage 1 (the mildest) to stage 5 (most severe):

• Stage 1 Coats disease: Your eye care specialist notices abnormal blood vessels in your child’s eye, but they’re not causing any issues or symptoms.
• Stage 2 Coats disease: The affected blood vessels in your child’s eye start leaking. This will probably affect your child’s vision.
• Stage 3 Coats disease: Your eye care specialist will classify the Coats disease as stage 3 if it causes a detached retina in your child’s affected eye.
• Stage 4 Coats disease: Stage 4 Coats disease causes glaucoma in your child’s eye.
• Stage 5 Coats disease: This is sometimes called end-stage Coats disease. It causes blindness in the affected eye.

What causes Coats disease?

Experts aren’t sure what causes Coats disease. It usually happens without a specific cause (idiopathically).

Coats disease isn’t a genetic disorder. This means it’s not passed through generations of a family — it’s not hereditary.

Risk factors

Anyone can develop Coats disease, but it’s much more common in children assigned male at birth (AMAB). Children AMAB are three times more likely to have Coats disease than those assigned female at birth (AFAB).

Coats disease can develop at any age:

• Providers usually diagnose kids and teens before they’re 16.
• It’s rare, but babies can be born with Coats disease, and it can develop in some infants.
• Around one-third of people with Coats disease are adults older than 30.

How is Coats disease diagnosed?

An eye care specialist will diagnose Coats disease with an eye exam.

They’ll look at your child’s eyes (including inside them). They’ll examine your child’s eyes and vision with a visual acuity test.

Your eye care specialist might need one or a few imaging tests to diagnose Coats disease, including:

• Optical coherence tomography (OCT).
• Angiography.
• Ultrasound.
• MRI (magnetic resonance imaging).
• CT scan (computed tomography scan).

How is Coats disease treated?

How Coats disease is treated depends on which stage your child has. If an eye care specialist diagnoses them early (stage 1 or early in stage 2), your child may not need any treatment. Your eye care specialist will regularly check your child’s eyes for changes in their retina’s blood vessels.

If your child has more severe symptoms or is in a later stage, Coats disease treatments include:

• Cryotherapy: Cryotherapy is a treatment where your healthcare provider applies extreme cold to freeze and destroy abnormal tissue. They’ll freeze the affected blood vessels in your child’s retina to prevent them from leaking anymore.
• Medication: An ophthalmologist can inject anti-vascular endothelial growth factor (VEGF) drugs into your child’s retina. This can stop their blood vessels from leaking and prevent a retinal detachment.
• Surgery: If your child has later-stage Coats disease or has experienced a detached retina, they’ll need surgery to repair the damage.

How can I prevent Coats disease?

Because it happens randomly with no cause, there’s nothing you can do to prevent Coats disease.

Visit your eye care specialist for follow-up eye exams to monitor any changes in your child’s retina after they’ve been diagnosed.

What can I expect if my child has Coats disease?

How your child’s eye and vision will be affected by Coats disease depends on what stage it was diagnosed at, and how well their eye responds to treatment. Studies have found that the older kids are when they develop Coats disease, the less likely it is that they have severe cases that progress to later stages.

If Coats disease is diagnosed early in stages 1 or 2, there’s a good chance your child won’t have severe long-term effects. However, they might have reduced or low vision in their affected eye, even after treatment.

Later-stage Coats disease has a higher risk of blindness in the affected eye.

What are Coats disease complications?

While your child has Coats disease, they’ll have an increased risk for other conditions that can affect their eye, including:

• Glaucoma.
• Cataracts.
• Uveitis.
• Neovascularization (developing new, abnormal blood vessels).

When should I see my healthcare provider?

See your healthcare provider or eye care specialist as soon as you notice any changes in your child’s eyes or vision.

Go to the emergency room if they have any of the following symptoms:

• A sudden loss of vision.
• Severe eye pain.
• They see new flashes or floaters in their eyes.

What questions should I ask my provider?

Questions you may want to ask your provider include:

• Which stage of Coats disease does my child have?
• How often will they need follow-up exams?
• Will they need treatment?
• Which treatments will they need?
• How much will Coats disease affect their vision?

What is the difference between Coats disease vs retinoblastoma?

Coats disease and retinoblastoma are both conditions that affect the retinas in kids’ eyes.

Coats disease happens when a child’s retinal blood vessels develop abnormally and leak fluid into their eye.

Retinoblastoma is a rare type of cancer that grows on the retina. If the tumor hasn’t spread beyond the eye, most children with retinoblastoma live cancer-free after treatment.

Both conditions have similar symptoms, especially early on in their progression. Visit your eye care specialist right away if you notice any symptoms or changes in your child’s eyes.

A note from Cleveland Clinic

Coats disease is a rare condition that affects the tiny blood vessels in your child’s retina at the back of their eye. The best chance to lessen its impact on their eye and vision is to catch Coats disease in an early stage. Visit your healthcare provider or eye care specialist as soon as you notice any changes in your child’s eyes or their ability to see.