Coats' usually occurs in children or teenagers under the age of 18, although the disease has been diagnosed in patients as young as four months. Coats' is often detected by flash photography in a digital photo.
Article continues below
Back in 1912, Dr. George Coats described the disease like this: occurrence unilaterally in young male patients, there are no systemic diseases, there are exudates below the retinal vessels and retinal hemorrhages, and it progresses to retinal detachment, cataract, atrophy, or glaucoma.
Blood vessels provide blood and oxygen to the retina and when they are dilated, abnormally twisted, and leaky, we have Coats' disease.
Those abnormal blood vessels are causing a buildup of fatty material in the retina and when there's too much of, the retina may detach and when that happen the consequence is loss of vision.
We all know the red-eye effect when we took a picture of somebody. When an eye is affected by Coats, light reflects off cholesterol deposits and it will glow yellow in photos.
Maybe you have noticed the yellow glow when looking at the pictures of you kid and you attributed it to the camera malfunction.
The first problem with a modern photo equipment is that it is so advanced that it mimic natural light and Coats' may not show up on the professionally taken photos.
Will it show or not depends of the angle of the light entering the camera lens, is the photo taken early in the morning, midday, late in the afternoon, inside or the outside... and it will show up on maybe 5 out of 50 photos you have taken with your camera.
But if it didn't happen with anyone else, that's the sign you should take you kid to the doctor immediately.
Another symptom is deterioration of eyesight which happens gradually and may be hard to notice until is too late.
Then, when one eye is affected by Coats, another eye may try to compensate and the result is some loss of depth perception. Sometimes, strabismus (eye turning outward or inward) is present.
There are two problems with this disease. First, we don't know what's the cause. And we don't know what are risk factors. We know there is no hereditary component.
The second problem is, it may be successfully treated if caught early but it usual isn't simply because patients are often too young to articulate their symptoms. That means, when it is diagnosed properly, it is usually in a very late stage.
The disease progress is divided into five stages.
First, there are abnormal blood vessels in the retina but they don't leak yet.
Second, there is leakage from the vessels into the retina. If the amount of fluid is small, the vision may be perfectly normal. If there is a lot of fluid leaked, vision damage occurs.
Third, when enough fluid accumulates, that may cause the retina to detach.
The fourth stage is if the disease is further complicated with raised pressure of the eye, glaucoma.
The stage five is the final stage when the eye is painful because there is a lot of pressured inside it and the person becomes blind.
Coats' patients may experience few or no symptoms while others may have severe involvement.
Coats' disease may be diagnosed on a routine eye exam when a cataract or abnormal blood vessels might be seen, and the doctor may also see abnormalities of blood vessels or a retinal detachment.
One of the problems is that we humans are adaptive species. When there is a problem in one eye, the body will compensate with another. That make the diagnosis harder than it would otherwise be.
Now, what to do?
Well, there are not many options. Laser or freezing are used to constrict the abnormal blood vessels and that stops the leakage of fluid. In advanced stages, surgery is needed to treat retinal detachment.
However, we again have two problems here.
First, treatment is of limited value, which means it doesn't guarantee there will no further problems with the blood vessels.
Second, if the leak is very closed to the optic nerve, there is a big chance that the treatment will damage the nerve and that means the end of vision or in the best case scenario worsening of vision.
The most of patients with Coats’ disease have poor vision in the affected eye and we must monitor them to check how the vessels are doing.
But, there are two good news: In older children and young adults, Coats’ disease can have a much milder and slower effect on the retina. Occasionally the disease stops on its own and may even reverse. ■