Coats disease is a congenital eye disorder caused by a genetic defect. Coats disease leads to complete blindness and has limited curative treatment options.
What is Coats disease?
Coats disease is a rare congenital eye disorder that affects boys far more often than girls. The blood vessels of the retina are dilated and permeable, allowing blood and ocular fluid to pass under the retina. This causes edema, which – if the disease is left untreated – leads to detachment of the retina and eventually to complete blindness. Coats’ disease usually occurs on one side – a typical feature is a milky white film over the eye. Pain does not usually occur. Sometimes glaucoma results from an increase in intraocular pressure. In less than ten percent of those affected, there are no symptoms at all. In the long term, Coats’ disease basically threatens complete blindness.
Causes
The causes of Coats disease are currently unknown. However, numerous investigations in the family environment of affected individuals suggest that there is a hereditary predisposition to the development of Coats disease. A retardation of the X chromosome is suspected. The cause of blindness, to which Coats’ disease usually leads, is the defective blood vessels in the eye. As a result of this defect, bulges (aneurysms) develop in the blood vessels of the retina, causing the blood vessels to become porous and leak fluids. The fluids (blood, cholesterol crystals, lipids) are deposited under the retina and lead in the further course to a detachment of the retina. Along with this, the patient’s vision will deteriorate more and more, eventually leading to blindness.
Symptoms, complaints, and signs
The first symptoms in Coats disease usually appear in the first or second decade of life. Boys are affected much more frequently than girls. In addition, more than 90 percent of cases are unilateral eye disease caused by aneurysms of the ocular blood vessels. Secondary strabismus and leukocoria are usually observed as initial symptoms. In leukocoria, the fundus of the eye appears white rather than the usual red on photographs taken with a flash. In the affected eye, patients often have blurred vision. Spatial vision is impaired. However, in young children the loss of vision is often not noticed at first. However, not every course of the disease is the same. Thus, the progression of the disease can be temporarily or even permanently halted. In a few cases, an improvement of the symptoms has even been observed. However, in most cases, retinal detachment occurs, which then leads to blindness of the affected eye. The course of the disease is often much more fulminant in children under five years of age than in older children. In severe cases, removal of the eyeball may be necessary.
Diagnosis and course
If Coats disease is suspected – secondary strabismus may be a first, visible sign – the ophthalmologist will perform an ophthalmoscopy (examination of the back of the eye). To do this, the doctor shines a light on the back of the eye to identify altered blood vessels. The examination is painless and takes only a few minutes. Patients suffering from Coats’ disease initially show a secondary strabismus; it is also particularly noticeable that eyes photographed with a flash light do not appear red, but milky white. During this phase of the disease, the patient’s spatial vision is impaired, and he also perceives images only blurred. The course is usually painless – only when the intraocular pressure becomes greater does the patient feel pain in the eye. The increase in intraocular pressure can lead to “glaucoma“, a frequent concomitant disease of Coats’ disease. In affected infants, the disease usually goes unnoticed, as they are unaware of the steady loss of vision. Moreover, the course is different in each patient – while in most patients the deterioration is continuous, some patients report an intermittent deterioration. In a few cases, regression has even been observed. However, Coats disease usually leads to complete detachment of the retina and thus to complete blindness.
Complications
Coats’ disease causes severe discomfort in the eyes of the affected person and further causes loss of vision. In the worst case, this can also lead to complete blindness, which usually cannot be cured. It is not uncommon for visual complaints or blindness to lead to severe psychological restrictions or depression. Those affected not infrequently suffer from inferiority complexes or reduced self-esteem. Especially for young people, dealing with vision loss is relatively difficult. Those affected may continue to squint and see only blurredly. This leads to veil vision and in some cases also to double vision. Furthermore, glaucoma or cataracts can develop and the eyes have different eye colors. Complete blindness usually occurs if no treatment for the disease is given. The treatment itself can be done relatively easily and does not lead to any particular complications. The vision problems can be solved and complete blindness can be prevented. Special complications do not occur. Furthermore, pain is also limited by the treatment. Coats disease does not lead to a reduction in life expectancy.
When should you see a doctor?
When vision is impaired, a doctor is generally needed. If there is a misalignment of the eyes or other peculiarities of the pupils, a doctor should be consulted. Burst blood vessels in the eyeball, redness of the eyes, and clouding of the cornea should be examined and treated by a physician. Since Coats’ disease is a genetic disorder, in many cases an irregularity is detected immediately after birth. Often, the diagnosis can be made after the initial examinations shortly after delivery. In a routine procedure, the newborn is intensively examined by the nurses, midwives or doctors present. Eye dysfunction can therefore be tested at this stage of life. If parents notice abnormalities in their children’s vision during the growth and development process, they should consult a doctor immediately. If there are more accidents in everyday life or the toddler regularly reaches next to objects, he or she needs medical help. If there is any suspicion that the child is completely unable to see, a check-up visit to a doctor is advisable as soon as possible. If the child cries continuously, this may be an indication of existing pain or strong internal pressure in the eye. A physician should be consulted so that treatment can be initiated.
Treatment and therapy
If Coats disease is detected early – before the first detachments of the retina – it can be treated well. The goal here is to preserve some of the vision. An ophthalmologist can localize altered blood vessels and, in a subsequent step, obliterate them using a laser. Good treatment success can also be achieved in this phase of the disease with cold therapy. Both therapies prevent the leakage of fluid and thus prevent detachment of the retina. If Coats’ disease is more advanced and the retina has already detached, Coats’ disease can no longer be treated curatively. The physician can only remove the affected part of the vitreous body of the eye and/or the retina. To rule out a malignant background – such as retinoblastoma – it may be helpful to remove the eye completely. Vision cannot be restored after detachment of the retina – interventions described can only relieve intraocular pressure and thus reduce or completely eliminate pain in the eye.
Outlook and prognosis
Coats disease offers a relatively good prognosis. In most cases, only one eye is affected by the disease, which can be surgically removed. Affected individuals can subsequently lead a normal, symptom-free life. However, there is a great risk of relapse in Coats’ disease. In the event of a relapse, the therapeutic measures must be repeated. Drug treatment of the pain is associated with side effects and interactions. If left untreated, the disease progresses progressively and leads to complete blindness of the affected eye. An effective treatment is not yet available.The therapy focuses on removing the diseased components of the body and treating the pain with medication. Well-being is reduced during treatment. After completion of therapy, a normal life is often possible. In the case of complete blindness, sufferers are dependent on assistance throughout their lives. Life expectancy is not reduced insofar as the retinal edema has been completely removed. Further preventive measures are necessary to avoid a relapse, which is usually more severe and significantly worsens the prognosis. The prognosis is determined by the physician, taking into account the symptom picture and the chosen therapy.
Prevention
Because Coats disease is thought to have a hereditary background, it cannot be prevented according to current medical research. However, if Coats disease is detected early, the consequences of the disease – usually complete blindness – can be prevented. For this purpose, some prophylactic therapies are available, which aim to preserve some of the visual power.
Follow-up care
After treatment of Coats disease by laser therapy, the patient should avoid physical exertion for several days. Active participation in road traffic is not possible 24 hours after treatment. In case of abnormalities or complaints, the attending physician should be notified immediately. He will also decide when it is time for the first check-up and whether eye drops or eye ointments need to be prescribed after the procedure. The treatment of Coats’ disease is only symptomatic. Therefore, symptoms can flare up at any time even after successful therapy. In addition, Coats’ disease increases the likelihood of developing increased intraocular pressure (glaucoma) or lens opacity (cataract). Therefore, regular ophthalmological check-ups are essential. The interval between examinations is determined by the treating ophthalmologist. In some cases, despite regular therapy and control, a gradual loss of vision cannot be stopped, and in the worst case patients lose the affected eye. This is a great psychological burden for the usually very young patients, which is why psychological care should be considered. Support from trained professionals facilitates healthy psychological development and supports the self-confidence of those affected.
Here’s what you can do yourself
The congenital disorder is based on a genetic defect. The possibilities for self-help are very limited with this disease. A cure cannot be achieved despite all self-responsible attempts. In everyday life, care should be taken to maintain and improve well-being. The zest for life should be promoted so that the patient has sufficient emotional resources available in dealing with the disease. A positive attitude, encouraging words from relatives and a stable social environment help the patient to cope with everyday life. Although many activities cannot be performed due to the symptoms, a sense of achievement should be encouraged in children. An exchange with other sufferers or in self-help groups can help to obtain mutual support and tips. Open questions are clarified, so that in the daily routine a better handling of the complaints can take place. The patient should be informed in good time and comprehensively about his or her illness and the consequences. A self-confident and honest approach to the disease is helpful for the entire environment. This reduces inappropriate expressions or undesirable behavior. In a large number of cases, people from the immediate environment experience their own insecurity or excessive demands with the situation due to ignorance, which leads to misunderstandings or hurtful events for the person affected. This should be prevented whenever possible.