What is exophthalmos

Exophthalmos is also known as proptosis, is a medical term for a bulging or protruding eyeball or eyeballs. Exophthalmos is most often caused by thyroid eye disease. There’s also a small risk of the optic nerve (which transmits signals from the eye to the brain) becoming compressed if you have exophthalmos, which may affect your sight permanently if it isn’t treated quickly.

Many of the symptoms of thyroid eye disease tend to improve over time, although this can take a number of years. There’s a chance your eyes will continue to protrude if corrective surgery isn’t carried out.

Some people with exophthalmos are left with long-term vision problems, such as double vision. However, permanent visual impairment is rare if the condition is identified and treated promptly.

Treatment for exophthalmos (bulging eyes) largely depends on what is causing the problem.

In some cases, an ophthalmologist (eye specialist) may feel immediate treatment isn’t necessary. You may only be advised to have regular examinations to monitor your condition.

Exophthalmos is a symptom of which endocrine disorder?

Graves disease is an autoimmune disorder that leads to an overactive thyroid gland (hyperthyroidism). An autoimmune disorder is a condition that occurs when the immune system mistakenly attacks healthy tissue.

Exophthalmos causes

One of the main causes of exophthalmos in the US is thyroid eye disease, also known as Graves ophthalmopathy. Graves disease is the most common cause of hyperthyroidism. Graves disease is due to an abnormal immune system response that causes the thyroid gland to produce too much thyroid hormone. Graves disease is most common in women over age 20. But the disorder can occur at any age and can affect men as well.

Graves disease is an autoimmune condition that affects around one in every three people with an overactive thyroid gland (hyperthyroidism). Graves disease is particularly common in women aged 30-50 and people who smoke.

An autoimmune condition is where the immune system (the body’s defence against illness and infection) mistakenly attacks healthy tissue.

In the case of thyroid eye disease, the immune system attacks the muscles and fatty tissues around and behind the eye, causing them to become inflamed (swollen).

Thyroid eye disease can also occasionally affect people with an underactive thyroid gland (hypothyroidism) and, in rare cases, people with seemingly normal thyroid function.

Other causes of bulging eyes

Exophthalmos can also have a number of other causes, but these are generally less common than thyroid eye disease.

Other causes of exophthalmos can include:

• an injury to the eyes
• bleeding behind the eyes
• abnormally shaped blood vessels behind the eyes
• an infection of the tissue in the eye socket
• cancerous tumours – such as those caused by neuroblastoma and some soft tissue sarcomas

Exophthalmos can also affect newborn babies if they’re born with eye sockets that are shallower than normal.

Exophthalmos complications

Depending on what’s causing your bulging eyes, you may also have other associated symptoms. For example, if exophthalmos is caused by a thyroid eye disease, your eyes may also be:

• inflamed, red and painful
• dry and “gritty”
• tearful
• sensitive to light (photophobia)

You may also experience some double vision.

In severe cases of exophthalmos, you may not be able to close your eyes properly. This can damage your corneas (the transparent tissue that covers the front of your eye) by causing them to dry out.

If your corneas become very dry, an infection or ulcers (open sores) may develop. These could damage your vision if left untreated.

Exophthalmos diagnosis

If you’re referred to an ophthalmologist, they’ll check how well you’re able to move your eyes. They may also use an instrument called an exophthalmometer to measure how far your eyeball protrudes.

If the ophthalmologist wants to examine your eye socket in more detail, a computerized tomography (CT) scan or magnetic resonance imaging (MRI) scan may be carried out.

You may also have a blood test to assess how well your thyroid gland is working and you may be referred to an endocrinologist (a specialist in conditions affecting glands and hormones) if you’re found to have abnormal thyroid hormone levels.

Exophthalmos treatment

If exophthalmos is being caused by thyroid eye disease, the following treatments are often helpful:

• medication to correct the level of thyroid hormones in your blood – this won’t necessarily improve the problems with your eyes, but may stop them getting worse
• corticosteroid medication given directly into a vein (intravenously) – this can help reduce the inflammation associated with the condition
• corrective surgery – this may be carried out to improve the appearance of your eyes once the inflammation is under control

Other useful measures include stopping smoking, using artificial tears to reduce eye dryness and irritation, and wearing special lenses to correct double vision.

In other cases, treatment will vary depending on the underlying cause. For example, treatments such as radiotherapy, chemotherapy and/or surgery may be recommended if exophthalmos is caused by a tumor.

Treating thyroid eye disease

If you have thyroid eye disease, your treatment may involve several different stages. This is because the condition tends to progress through two main phases:

• an “active” phase – when symptoms caused by inflammation of the eyes, such as dryness and redness, are prominent and you may be at risk of vision problems
• an “inactive” phase – when the condition has “burnt out” and many of the symptoms settle down, but you may be left with some long-term problems (including protruding eyes)

Typically, the initial active phase lasts for between several months and around two years.

Some of the main treatments you may be offered if you have thyroid eye disease are described below.

Treating your thyroid problems will not necessarily improve your eye-related symptoms, but it may help prevent other problems associated with abnormal thyroid levels. It may also help the problems affecting your eyes from getting worse.

Correcting thyroid hormone levels

If you have an overactive thyroid gland (hyperthyroidism) or an underactive thyroid gland (hypothyroidism), you’ll usually be offered medication to help correct the level of thyroid hormones in your blood.

An overactive thyroid (hyperthyroidism) is usually treatable.

You’ll normally be referred to an endocrinologist (specialist in hormone conditions) to plan your treatment.

The main treatments are:

• medication
• radioiodine treatment
• surgery

Medication

Medicines called thionamides are a common treatment for an overactive thyroid. These stop your thyroid producing excess hormones.

The main types used are carbimazole and propylthiouracil.

You’ll usually need to take the medicine for a month or two before you notice any benefit. You may be given another medication called a beta blocker to quickly relieve your symptoms in the meantime.

Once your thyroid hormone level is under control, your dose may be gradually reduced and then stopped. But some people need to continue taking medication for several years or possibly for life.

Side effects of medications

During the first couple of months, some people experience the following side effects:

• feeling sick
• headaches
• aching joints
• an upset stomach
• an itchy rash

These should pass as your body gets used to the medication.

A less common but more serious side effect is a sudden drop in your white blood cell level (agranulocytosis), which can mean you’re very vulnerable to infections.

Contact your doctor immediately if you get symptoms of agranulocytosis, such as a fever, sore throat or persistent cough so a blood test can be carried out to check your white blood cell level.

Radioiodine treatment

Radioiodine treatment is where radiation is used to damage your thyroid, reducing the amount of hormones it can produce. It’s a highly effective treatment that can cure an overactive thyroid.

You’re given a drink or capsule that contains a low dose of radiation, which is then absorbed by your thyroid. Most people only require a single treatment.

It can take a few weeks or months for the full benefits to be felt, so you may need to take one of the medications mentioned above for a short time.

The dose of radiation you’re given is very low, but there are some precautions you’ll need to take after treatment:

• avoid prolonged close contact with children and pregnant women for a few days or weeks
• women should avoid getting pregnant for at least six months
• men shouldn’t father a child for at least four months

Radioiodine treatment isn’t suitable if you’re pregnant or breastfeeding. It’s also not suitable if your overactive thyroid is causing severe eye problems.

Surgery

Occasionally, surgery to remove all or part of your thyroid may be recommended.

This may be the best option if:

• your thyroid gland is severely swollen (a large goiter)
• you have severe eye problems resulting from an overactive thyroid
• you can’t have the other treatments mentioned above
• your symptoms come back after trying the treatments mentioned above

Removing the entire thyroid gland is normally recommended, as this cures an overactive thyroid and means there’s no chance of the symptoms coming back.

But as a result, you’ll need to take medication for the rest of your life to make up for not having a thyroid – these are the same medications used to treat an underactive thyroid.

General measures

You may also be advised about things you can do, and treatments that are available, to relieve some of the symptoms associated with the active phase of thyroid eye disease.

These include:

• stopping smoking if you smoke, as it can significantly increase the risk of eye problems becoming more severe
• raising the head of your bed – for example, using extra pillows – which may help reduce some of the puffiness around your eyes
• wearing sunglasses if you have photophobia (sensitivity to light)
• trying to avoid exposing your eyes to irritants such as dust
• using eye drops to help relieve soreness and to moisten your eyes if you have dry eyes
• wearing glasses containing special prisms designed to help correct double vision

If your thyroid eye disease is mild, these measures – along with the medications to correct your thyroid hormone levels mentioned above – may be all the treatment you need.

Corticosteroids

In more severe cases, when the eyes are particularly painful and inflamed during the active stage of thyroid eye disease, corticosteroids may be recommended by your doctor.

Corticosteroids are powerful medications that can help bring the inflammation associated with thyroid eye disease under control. They can help ensure the condition is stable before any type of surgery (see below) is considered.

In many cases, corticosteroids given directly into a vein (intravenously) are recommended. This is because taking corticosteroid tablets over a long period of time can have significant side effects.

A typical course of treatment with intravenous corticosteroids involves weekly treatments over a 10-12 week period. You should start to notice an improvement in your condition after a week or two.

Severe side effects of intravenous corticosteroids are uncommon, but you may experience some short-lived problems for a few days following the treatment sessions, such as:

• feeling agitated
• having difficulty sleeping
• headaches
• blushing of the neck and face

Radiotherapy

Occasionally, orbital or retrobulbar radiotherapy may be considered during the active stage of thyroid eye disease if corticosteroids haven’t been effective. It may also be combined with corticosteroids.

This treatment uses high-energy radiation, usually X-rays, to destroy cells. Low doses of radiation can be used on the tissues and muscles in the eye socket to help reduce the swelling.

During treatment, you’ll lie down and a special shell will be placed over your head to keep it still. A machine is used to carefully direct beams of radiation at the area being treated.

This is usually done on an outpatient basis, which means you won’t need to stay in hospital overnight. Treatment typically involves around 10 sessions over a two-week period.

Radiotherapy can cause some side effects, although these should be minimal as the treatment will be confined to a specific area and shouldn’t affect other parts of your body. However, possible side effects may include:

• short-term worsening of your eye symptoms
• cataracts
• in rare cases, sight-threatening retinopathy (damage to the layer of tissue at the back of your eye)

Surgery

In some cases, surgery may be considered as a treatment for exophthalmos if you have severe or persistent symptoms.

For example, surgery may be considered to improve the appearance of the eyes if exophthalmos has been in the inactive phase for a few months. Medical treatment alone won’t necessarily reverse the protrusion of the eyes.

Surgery may also be carried out during the active phase of thyroid eye disease if there’s an immediate threat to your vision due to compression of the optic nerve (which transmits signals from the eye to the brain).

Surgery may also be effective if the exophthalmos is caused by other problems, such as issues with the blood vessels behind the eyes.

Types of surgery

There are three main types of surgery that may be carried out on people with exophthalmos, although it’s unusual for someone to have all three. These are:

1. Orbital decompression surgery – (see below) where a small amount of bone is removed from your eye socket(s)
2. Eyelid surgery – where surgery is carried out to improve the position, closure or appearance of the eyelids
3. Eye muscle surgery – where surgery is carried out on your eye muscles to bring your eyes into alignment and reduce double vision

These procedures are usually carried out under general anesthetic, which means you’ll be asleep. Depending on the type and extent of the operation you have, you may need to stay in hospital for up to a few days afterwards.

Orbital decompression surgery

Orbital decompression surgery is most often carried out to improve the appearance of the eyes of people with thyroid eye disease who are affected by exophthalmos. It may also be required to reduce any pressure on the optic nerve.

During the procedure, a small amount of bone is removed from your eye sockets (orbits) and some of the fat surrounding the socket may also be removed.

This allows any excess tissue that’s pushing the eyeballs forward to move down into the space below. It also allows your eyes to sit further back in your head, so they don’t protrude forward as much.

This procedure is carried out under general anaesthetic and normally involves making incisions near where your eyelids meet in the inner corner of your eyes (the point nearest the nose). You may need to stay in hospital for a day or two after this procedure, so your recovery can be closely monitored.

Possible complications that can occur following orbital decompression surgery include:

• persistent double vision
• a build-up of blood in the eye socket (hematoma)
• infection where the incision is made

If you’re considering having orbital decompression surgery, ask your doctor or surgeon to explain the benefits and risks of the procedure to you.

Treating other causes of exophthalmos

For most other problems that cause exophthalmos, treatment will vary, depending on the underlying cause.

For example, if you have an infection affecting the tissue in your eye socket, such as cellulitis, your ophthalmologist may prescribe antibiotics to treat the infection. They may also need to carry out a procedure to drain any abscesses that have developed.

If you have a tumor behind your eye, your doctors will discuss treatment options with you. For most types of cancer, treatment involves one or more of the following:

• chemotherapy – where medication is used to kill the cancerous cells
• radiotherapy – where radiation is used to kill the cancerous cells
• surgery to remove the cancerous tumor