Coats’ disease is an eye condition that can eventually lead to blindness. This rare disorder was first described by George Coats in 1908. It’s characterized by problems with the blood vessels in your eye.
What Causes Coats’ Disease?
Coats’ eye disease is considered an idiopathic condition. Researchers don’t know exactly what causes it.
This condition is one of a number of rare eye diseases that result from blood vessel problems in your eye. Similar conditions include Norrie disease and persistent fetal vasculature (PFV).
Normally, your veins supply blood and oxygen to your retina. Your retina is one of the most important parts of your eye. It’s the nerve layer at the back of your eyeball that senses light. It conveys these images to your brain. The center of the retina is the part of your eye that you use to distinguish fine details.
In people with Coats’ disease, though, the blood vessels that interact with your retina become enlarged, twisted, and leaky. This leakage is called exudate and includes fats and proteins that normally stay contained within your blood vessels. This leads to many downstream problems that gradually worsen with time.
Currently, the disease isn’t considered heritable. This means that it’s seemingly not passed down from parents to offspring. Still, research is ongoing, and preliminary data indicate that mutations in a handful of genes could be involved.
One of these potential genetic causes is a gene called Norrie disease protein (NPD). This gene definitely plays a role in the development of retinal blood vessels. Some evidence indicates that changes in this gene could be responsible for this condition.
Who Gets Coats’ Disease?
Coats’ disease is relatively rare. Only 0.09 out of every 100,000 people in the population will develop Coats’ disease at some point in their life.
Most cases are diagnosed when you’re still in your first two decades of life. This is known as the juvenile version of Coats’ disease. Two-thirds of juvenile cases are diagnosed before age 10, though the average age of diagnosis is between eight and 16 years old.
The condition can also affect adults. About one-third of affected people are over 30 years old when they’re diagnosed with the adult version of Coats’ disease. The average age for adult diagnosis is 47 years old.
In both age groups, the disease is much more common in males than in females. The exact rate varies from study to study, but some estimates show that it occurs in a three-to-one ratio of males to females.
How Is Coats’ Disease Diagnosed?
Your eye doctor will need to evaluate your family and health history in order to determine the cause of your eye problems. They’ll also need to thoroughly examine your eye using a number of different techniques.
One technique is optical coherence tomography (OCT). This allows your doctor to take detailed images of your eyeball.
Your doctor may also look for signs of leukocoria in your eye. Normally, when a light is flashed into your pupil, the reflected light looks orange or reddish. In people with Coats’ disease, this light looks white instead.
What Are Coats’ Disease Symptoms?
The symptoms of Coats’ disease progress through five distinct stages. The first stage is defined by the observation of abnormal blood vessels. Leakage hasn’t started yet.
In the second stage, leakage begins to affect your retina. This stage looks different for everyone. Your vision may be affected. The amount of visual decline depends on how much leakage there is and the size and area of the retina that’s affected. Your vision will be the worst when there’s a lot of leakage at the center of your retina.
The disease progresses to the third stage when your retina detaches.
The fourth stage involves glaucoma, which involves increased pressure inside of your eye due to fluid build-up. This may be painful.
Stage five is the final stage of Coats’ disease: Your eye becomes blind. The pain from stage four may persist, or pain may develop for the first time as fluid build-up continues in stage five.
Coats’ disease can also lead to a number of secondary complications. These include:
- Cataracts. This occurs when the lens within your eye becomes cloudy. Cataracts can make it difficult to see.
- Uveitis. Your eye becomes inflamed.
- Phthisis bulbi. This condition causes your eyeball to shrink.
- Rubeosis iridis or neovascular glaucoma. Your iris could become reddish due to the growth of new blood vessels.
Coats’ disease usually develops in only one eye. It only occurs in both eyes about 5% of the time. In these cases, the second eye is often only mildly affected.
Sometimes, an early sign is when one of your eyes is crossed inward or outward. On the other hand, you may not have any symptoms at all when you’re diagnosed with Coats’ disease. About 8% of cases are coincidentally diagnosed during a routine eye exam.
What Are Coats’ Disease Treatments?
The treatments for Coats’ disease are designed to keep your symptoms from progressing. The treatment that’s right for you depends on your symptoms and the stage of your condition. If your vessels aren’t leaking when you’re diagnosed, then your doctor will simply monitor your condition.
Potential treatments include:
- Cryotherapy. This is a freezing treatment that’s designed to restrict your blood vessels. It should slow down or prevent leaking in the early stages of Coats’ disease.
- Photocoagulation. Your physician uses lasers to heat and destroy abnormal blood cells. This can be done alone or in combination with cryotherapy. It’s most helpful early on.
- Eye injections. This could include medications like steroids or a newer treatment called anti-vascular endothelial growth factor therapy (Anti-VEGF). This is meant to reduce leakage and lower your risk of retinal detachment.
- Vitrectomy surgery. This treats more advanced stages of the disease. It’s a surgery used to reattach your retina.
Researchers are still in the process of developing new treatments for this condition. Look online or talk to your doctor to see if you qualify for any ongoing clinical trials.
What’s the Prognosis for Coats’ Disease?
You may still have poor vision even after treatment. The more severe your condition is when it’s detected, the harder it is to make a full recovery. The condition tends to be most severe when it’s first detected in children under the age of three.
In 47% of stage one and two cases, the blood vessel issues completely cleared up within 15 months following treatment. They partially improved in many other cases.
Results were less promising if the disease had already progressed to stage three.
Approximately 8% of cases continued to get worse even after treatment.
When Should You See Your Doctor?
You should see an eye doctor as soon as you start to notice any problems with your vision. You should also see your doctor if you have persistent pain in your eye.
