Understanding Proptosis and What to Do About It

What is proptosis?

Proptosis is a bulging or protruding of one or both of your eyeballs. Generally, a diagnosis of proptosis involves an eye protrusion of more than 2 millimeters. TED is the most common cause.

About 1 in 3 people with proptosis in one eye have excessively high thyroid hormone levels. About 9 in 10 cases of bilateral proptosis are linked to hormonal abnormalities.

More than 90 percent of people with thyroid-related eye disease experience eyelid retraction, where the upper or lower eyelid is drawn back. In severe cases, eyelid retraction may not allow you to fully close your eye, which can cause eye dryness. Dry eyes put you at risk of developing ulcers or infections that can cause vision loss.

If left untreated, TED can cause optic nerve compression that can lead to permanent vision loss.

Are there similar eye conditions?

Proptosis is also called exophthalmos, which comes from the Greek words that mean “bulging eyes.”

Buphthalmos is a condition with a similar name that comes from the Greek words for “Ox-eyed.” Buphthalmos is when an eye is larger than normal at or shortly after birth. It’s most commonly caused by congenital glaucoma.

What are the causes of proptosis?

Proptosis can be caused by a variety of conditions, but TED is the most common cause.

Thyroid eye disease (TED)

The autoimmune disorder TED is the most common cause of proptosis in one or both eyes. About 90 percent of people with TED have an overactive thyroid caused by the autoimmune condition Graves’ disease.

About 1 in 4 people with Graves’ disease develop TED.

Cancer

Proptosis in one eye can be an early symptom of cancer. It can be a symptom of primary cancers that start growing around your eyes, such as melanoma or carcinoma, or it can be a symptom of metastasized cancers that spread from somewhere else.

Breast cancer is the most common metastasized cancer that causes proptosis.

A 2018 case report described a 40-year-old woman who developed proptosis and headaches as the first symptoms of a type of blood cancer called multiple myeloma.

Trauma

A wide range of traumatic injuries can cause proptosis. For example, an older 2013 case report described a 23-year-old football player who developed proptosis after his helmet dislodged and hit him in the right eye.

Trauma to your eye can lead to a retrobulbar hematoma, which is congestion of blood deep in the tissue between your eye and skull. This buildup of blood can cause your eye to protrude forward.

Fracturing your skull around your eye can also potentially lead to proptosis due to air escaping your sinus and entering the area around your eye.

Infections

Severe sinus infections can lead to inflammatory conditions such as orbital cellulitis or orbital abscess. These inflammatory conditions can lead to swelling behind your eye that puts pressure on your eye and causes proptosis, most likely in one eye.

Blood vessel disease

Some types of blood vessel disease, such as the rare autoimmune disease granulomatosis with polyangiitis, cause abnormalities of your blood vessels that can lead to proptosis and other eye complications.

How is proptosis diagnosed?

A prompt diagnosis and treatment of proptosis are needed to minimize your risk of permanent vision loss.

An eye doctor can diagnosis proptosis by examining your eye. They can use a special tool called an exophthalmometer to measure your level of eyeball protrusion.

Your doctor will also review your medical history and ask you questions about your symptoms. They’ll likely order a variety of tests to find the underlying cause of your proptosis. Tests may include:

• blood tests
• thyroid function and auto-antibody tests
• renal function and C-reactive protein tests
• nasal swabs and blood cultures if an infection is suspected

Imaging tests such as computed tomography (CT) scans and magnetic resonance imaging (MRI) can help your doctor:

• search for tumor growth
• see the extent of the inflammation in your eye
• look for damage to your optic nerve

What is the treatment for proptosis?

Treatment options for proptosis depend on the underlying cause.

General treatment options

General treatments to help manage symptoms include:

• steroid injections to reduce inflammation
• eye drops to reduce inflammation and dryness
• quitting smoking
• wearing sunglasses to help with light sensitivity
• avoiding dust and other irritants

TED treatment

If your proptosis is caused by TED, you’ll need to treat the underlying thyroid disease. Treatment options include:

• medications such as teprotumumab (Tepezza) or methimazole
• radioactive iodine therapy
• thyroid surgery

Surgery

In severe cases of proptosis, orbital decompression surgery and extraocular muscle repair may be recommended to protect your vision. These surgeries increase vision in up to 82 percent of people.

Surgery may also be required if you have a tumor growing around your eye.

Cancer treatments

Proptosis is sometimes caused by cancerous tumors. Along with surgery, cancers of the eye are commonly treated with:

• radiation therapy
• chemotherapy
• immunotherapy
• targeted therapies

Who can develop proptosis?

The most common cause of proptosis is TED, and it’s more common in people who:

• smoke
• are older adults
• are female
• experience extreme physical or psychological stress
• take radioactive iodine for treatment
• have higher concentrations of anti-thyroid stimulating hormone receptor antibodies

What’s the outlook for people with proptosis?

Early diagnosis of proptosis is important to minimize your chances of developing complications.

In many cases, supportive treatment may be all that’s needed. About 66 percent of mild cases resolve within 6 months. About 95 percent of people with thyroid-related proptosis heal without permanent vision loss, but about 5 percent of people develop permanent double vision or visual impairment.

The takeaway

Proptosis is the medical term for bulging eyes. TED is the most common cause of proptosis. Other potential causes include cancer, eye injury, or infections.

It’s important to contact a doctor if you have proptosis. In severe cases, proptosis can lead to permanent vision loss. Receiving medical attention as soon as possible gives you the best possible chance of treating the underlying cause and minimize damage to your eye.