What is Coats' Disease?
Coats Disease is the name given to a medical condition which is characterized by exudative retinitis and has the following characteristics:
- Found normally in male patients
- Normally the retinitis is present unilaterally without any substantial evidence of a systemic illness
- These exudates are normally found below the retinal vessels
- It causes retinal hemorrhage
- If untreated this disease may cause, retinal detachment, cataracts, or glaucoma resulting with ultimately complete blindness in that eye.
What are Causes and Risk Factors for Coats' Disease?
Coats Disease does not have any known etiology. Studies do not point to any genetic link to this disease although some studies point to abnormal mutation of Norrie disease protein gene. Coats disease is found to affect males more than females.
What are Symptoms and Signs of Coats' Disease?
The primary symptom of Coats Disease is progressive decrease in vision of the patient. It is not recognized immediately as initially only one eye is affected and the patient is able to compensate the decreased vision with the other eye but after a period of time when the vision starts to severely decrease is when the real problem starts. Coats disease starts as early as infanthood and progresses over a period of time. Coats disease does not cause any pain and is unilateral which means it affects only one eye to begin with.
Coats Disease can be identified through a routine ophthalmological examination, although it is a rare occurrence and diagnosis is only confirmed when the disease has progressed enough that the child develops significant cataracts and the pupils have a yellow covering on them and there is complete retinal detachment. A routine exam will show dilated pupils and the physician can identify easily abnormalities in the blood vessels. A retinal detachment can also be seen clearly. In severe cases there will be significant retinal damage along with presence of glaucoma and atrophy of the optic nerves. Since Coats disease progresses slowly and the patient may not even recognize that the vision is deteriorating that it becomes difficult to diagnose it in the early stages until the patient loses more than half of the peripheral vision and there is significant development of cataracts. Once Coats Disease is suspected and diagnosed then it becomes extremely vital for the patient to have routine eye examinations to see the status of the disease and making sure that the health of the eye is not affected.
What are the Classifications of Coats' Disease?
There are five states of Coats Disease wfhich have been mentioned below:
Stage I: In stage 1 of Coats disease there is presence of telangiectasia only.
Stage II: In this stage there will be both telangiectasia as well as exudates.
Stage III: This is quite an advanced stage of Coats disease and is characterized by subtotal retinal detachment.
Stage IV: In this stage the Coats disease is severely advanced and there is total detachment of the retina.
Stage V: By this stage, the Coats disease has completely advanced and the affected individual loses vision completely.
What is the Treatment for Coats' Disease?
Although rare, in case if Coats disease is diagnosed in its early phase then laser treatment of the affected eye has been found to be successful albeit in a limited fashion in treating the condition. In some mild cases, the disease does not progress and stops advancing on its own without any treatment and in some cases the damage done has even been reversed. In more advanced stage of Coats disease, vitreoretinal surgery may be more effective and in severe cases enucleation may be necessary. The treatments required for various stages of the disease are as follows:
For mild form of Coats Disease which shows signs of progression, photocoagulation using laser technique along with cryotherapy has been found to be useful for treatment; however if this disease stops progressing then plain observation is all what is required.
In case Coats disease has reached an advanced stage then vitreoretinal surgery may be required and if the patient experiences severe pain in the eye then enucleation is required as a method of treatment.
There are also some forms of adjuvant therapy which can be done for Coats Disease like use of intravitreal triamcinolone which has been shown to be effective.
All these treatment modalities are helpful if this condition is diagnosed but the fact of the matter is that the occurrence of Coats Disease is so low and the symptoms experienced by the patient is hugely variable that it is always difficult to diagnose this condition in a timely manner and start treatment for it.