Coats Disease (also known as Coats’ Disease) happens when the small blood vessels (arteries and veins) in the eye become leaky. These blood vessels are in the back part of the eye called the retina. The retina is a part of the eye that helps us see.
In Coats disease, the blood vessels get bigger, twisted, and start to leak. This leaking can cause a buildup of fluid in the retina. If too much fluid builds up, it can make the retina pull away from the back of the eye (a retinal detachment. This can cause vision loss.
Coats disease usually affects just one eye, but sometimes the other eye can have problems too. It's more common in boys and it’s not passed down through families.
Fig. 1: Retinal detachment visible through the pupil (black spot in the center of the colored part of the eye) in a patient with Coats disease.
What Are the Signs of Coats Disease?
Signs of Coats disease in kids might include:
- Leukocoria (a white reflection in the pupil instead of a red one in photos)
- Blurry vision or trouble seeing
- An eye that looks crossed or turned out
- Pain if the pressure inside the eye goes up
Doctors can also see:
- Abnormal blood vessels in the retina
- Swelling in the retina
- The retina pulling away from the back of the eye
Fig. 2: Retinal photograph showing hemorrhages and exudates from leaking blood.
How is Coats Disease Diagnosed?
Doctors diagnose Coats disease by looking closely at the retina. They may also use special tests like ultrasound, fluorescein angiography (to see blood flow), and OCT (a scan that gives a detailed picture of the retina) to see inside the eye.
What Are the Stages of Coats Disease?
Coats disease can get worse over time. There are five stages from mild to severe:
- Stage 1: Abnormal blood vessels in the retina, but no leaking yet
- Stage 2: The vessels start leaking fluid into the retina. Vision may stay normal if only a little fluid leaks, but if a lot leaks, vision can get worse.
- Stage 3: The retina begins to pull away from the back of the eye (retinal detachment).
- Stage 4: Complete retinal detachment, along with high pressure in the eye (glaucoma).
- Stage 5: The eye goes blind and can become painful due to high pressure.
How is Coats Disease Treated?
Sometimes no treatment is needed and close monitoring is enough. Treatments, when needed, might include:
- Laser or freezing therapy (cryotherapy) to shrink the abnormal blood vessels and stop fluid leaks.
- Medicine (anti-VEGF) injected into the eye can reduce fluid leaks.
- Vitrectomy surgery may be needed severe cases.
Treatment aims to stop the disease from getting worse. Treatment works better when started early. Doctors will continue to check the eye after treatment to make sure the disease doesn’t come back or affect the other eye. Glasses and eye patch therapy may also help (Amblyopia).
How Will Vision Be Affected?
How well a person with Coats can see depends on:
- Their age
- How bad the disease is when it’s found
- How fast the disease gets worse
Young kids often have more severe disease. Older kids might have a milder form of the disease. Most patients have poor vision in the affected eye.
More information on Coats Disease can be found at:
EyeWiki
Genetic and Rare Diseases Information Center (National Institute of Health)
Updated: 10/2024
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