Ask the expert: what is thyroid eye disease?

Thyroid eye disease (TED), also known as Graves' orbitopathy or Graves’ eye disease, affects around 400,000 people in the UK. It damages the eye sockets and, in most cases, occurs in individuals with Graves’ disease, which is an autoimmune condition that causes the thyroid gland to become overactive. 

Here, we’ll explore what happens in TED, its symptoms and treatment. First, it helps to understand what the thyroid gland does and what happens in Graves’ disease. 

What is the thyroid gland?

Your thyroid gland is a butterfly-shaped gland that sits within the front part of your neck. It is responsible for producing thyroid hormones, which are essential for a host of bodily functions, including controlling your metabolism, body temperature, weight, and skin, hair and nail growth. 

In rare cases of individuals who are born without the ability to produce enough thyroid hormones, they need to take supplements for the rest of their lives to survive. 

What is Grave’s disease?

Graves’ disease is an autoimmune condition, where the immune system attacks the thyroid gland by producing antibodies called thyroid-stimulating immunoglobulins. 

These antibodies attach to the cells of your thyroid gland and stimulate these cells to make more thyroid hormones than you need — this is called hyperthyroidism. 

The consequences of hyperthyroidism include a heart palpitations, weight loss despite a normal or increased appetite, irritability, difficulty sleeping, shaking, tremors, muscle weakness and difficulty tolerating heat. 

Around a quarter of people with Grave’s disease will also develop TED. 

What happens in TED?

While the majority of individuals with TED have hyperthyroidism due to Graves’ disease, TED can also occur with normal thyroid levels or, in a minority of cases, with low thyroid levels (hypothyroidism). 

TED is an autoimmune condition that causes antibodies to attach to tissues within your eye sockets namely, muscles and fat. This triggers inflammation, which leads to eye pain, swelling and redness. 

What are the symptoms of TED?

The most common signs and symptoms of TED include swollen eyelids, red eyes that appear similar to eyes with conjunctivitis, dry and/or gritty eyes, swollen eye muscles, double vision, increased sensitivity to light, and increased fat production in the eye sockets. 

Fat accumulating in your eye sockets leads to eye bags, protruding eyes and lifting (retraction) of your eyelids; this can make your face look alarmed or as if you are staring. 

If you notice any of these symptoms, it is important to see your GP to get your thyroid levels checked. If your thyroid levels are normal, you may still have TED and may later develop raised thyroid levels. 

Who is most at risk of TED?

Your risk of TED is higher if you have Graves’ disease, a family history of Graves’ disease or other thyroid problems, or if you smoke. Smoking triggers inflammation throughout your body and significantly increases your risk of TED and more severe symptoms of TED. 

What are the stages of TED?

TED can be grouped into two stages: active and inactive. 

The active stage occurs at the start of the disease process, where the affected tissues are inflamed, swollen and red. As the disease progresses, inflammation reduces and you enter the inactive stage, which tends to last 12 to 18 months but can vary from one individual to the next. 

How is TED diagnosed?

TED is diagnosed during an ocular examination, that is, an examination of your eyes to check for swelling, protrusion of the eyes, double vision and red eyes. 

While red eyes are a common symptom of many eye conditions, including conjunctivitis and allergies, in TED, there is no associated discharge as happens during an infection such as conjunctivitis and the symptom persists for longer than a few weeks. 

You may also be referred for a blood test to check your thyroid hormone levels and check for antibodies that are present in Graves’ disease. 

Depending on the results of your examination and tests, the severity of your TED can be determined ie mild, moderate or severe. 

How is TED treated?

If you have TED and abnormal thyroid hormone levels, the first course of treatment is to get your thyroid hormone levels back within a healthy range. This is often enough to resolve TED. This may involve taking thyroid tablets, having radioactive iodine treatment or, in more severe cases of hyperthyroidism, removing your thyroid gland (thyroidectomy) followed by taking a daily thyroid supplement. 

If you smoke, you will be advised to quit, as smoking increases inflammation in your body and, consequently, worsens symptoms of TED. Also, treatments for TED and thyroid problems are less effective if you smoke. There is also emerging evidence that vaping can have similar effects as smoking regarding TED, so quitting vaping is also recommended.

Conservative treatments to relieve your symptoms include applying a cold compress to your closed eyes to ease swelling, having botulinum toxin injections to reduce retraction of your eyelids, and applying eye lubricants or plugging your tear ducts to soothe dry, itchy eyes. 

In moderate to severe cases of TED, you may need to see an orthoptist to treat astigmatism eg glasses fitted with prisms or lenses with patches. If these measures are not effective in treating your double vision, you may need squint surgery. 

You may also need to take anti-inflammatory medication and/or steroids to reduce the inflammation caused by TED. 

In certain cases, surgery may be recommended. Rehabilitative surgery can be performed during the inactive stage of the disease to correct protruding eyes (orbital decompression surgery), retracted eyelids, bulky eyebags and excess eyelid skin (blepharoplasty surgery). 

Surgery is only performed during the active phase of TED if the disease is threatening your vision.  

What are the potential complications of TED?

One of the main complications caused by TED is a change in appearance, which can have a significant impact on your self-esteem and confidence, as well as social and professional interactions. 

Double vision due to TED can also affect your quality of life as it may prevent you from driving and may interfere with other activities at home and work. Together with changes in your appearance, this can make you feel isolated and unlike your normal self.

Protruding eyes can increase your risk of eye infections as the front surfaces of your eyes (corneas) are more exposed to the air and vulnerable to drying out. 

Severe TED can cause permanent vision loss due to damage to your optic nerve (the nerve that runs from your eyes to your brain). Early treatment makes this outcome much less likely, which is why it is important to see your GP or optician as soon as possible if you’re concerned about your eyes and/or vision.