An Overview of Proptosis (Bulging Eye Disease)

Proptosis, also known as exophthalmos, is a bulging of one or both of the eyes. Some people naturally have eyes that appear to bulge due to normal variations in human anatomy.

Others develop proptosis as a result of various health conditions. The most common cause of proptosis is a thyroid condition called Graves' disease. Up to 50% of people with this condition develop Graves' ophthalmopathy, or thyroid eye disease (with eye symptoms like proptosis).

Symptoms

The main symptom of proptosis is an abnormal protrusion (bulging) of the eyes.

Proptosis can result in the bulging out of one eye (unilateral) or both eyes (bilateral). In normal eyes, the white part of the eye between the top of the iris (the colored part of the eye) and the upper eyelid is not visible. In bulging eyes, that white part is visible.

Other symptoms that can accompany bulging eyes include:

• Difficulty fully closing the eyes during sleep
• Difficulty fully closing the eyes while blinking
• Dryness of the cornea
• Discomfort
• Scarring
• Difficulty moving the eyes
• The perception among others that you are staring

Causes

The most common cause of bilateral bulging eyes is a thyroid condition known as Graves' disease.

In Graves' disease, swelling, fibrosis, and scarring of the tissue behind the eye muscles surrounding the eye may occur. This crowds the bony orbit where the eye sits, causing the eyes to bulge forward.

Unilateral proptosis can be caused by:

• Sinus infection that has spread into the orbit, creating an abscess
• Trauma
• Inflammation
• Arteriovenous malformations
• Orbital tumors
• Cancer

Glaucoma present from birth (primary infantile glaucoma) can also cause the eyes to enlarge.

Diagnosis

When a person develops proptosis, especially if it comes on suddenly or is in only one eye, medical testing should be done immediately. This can be a sign of a serious medical condition.

Bulging that occurs rapidly (over a few days) suggests different causes than bulging that has developed slowly over the years:

• Rapid bulging in only one eye may be due to bleeding in the eye socket, which can occur after surgery or injury, or infection or inflammation of the eye socket.
• Bulging that develops slowly in both eyes suggests Graves' disease.
• Bulging that develops slowly in one eye may be due to a tumor in the eye socket.

Your healthcare provider will start by taking your medical history and doing a physical exam. They may ask you:

• How long the bulging has been present
• Whether the bulging seems to be getting worse
• If you have other eye symptoms, such as dryness, increased tears, double vision, loss of vision, irritation, or pain
• Whether you've been having symptoms such as the inability to tolerate heat, increased sweating, involuntary shaking movements (tremors), anxiety, increased appetite, diarrhea, palpitations, and weight loss (common symptoms of Graves' disease)

Your healthcare provider will examine your eyes for redness, sores, and irritation using a slit lamp (a device used to examine the eye under high magnification). If your eyelids move as fast as your eyeballs when you look down or appear to be staring, it could indicate Graves' disease.

Your healthcare provider may also measure the degree of bulging with a ruler or a special instrument called an exophthalmometer. They may do more testing if measurements are outside normal ranges, especially if the bulging only affects one eye.

Tests may include:

• MRI
• Bloodwork
• Ultrasound
• Biopsy

Treatment

A main symptom of proptosis is dryness of the eye. Because the eyelids may not be able to close completely during normal blinking or sleeping, the cornea may dry out significantly. This dryness is uncomfortable and can cause scarring, which can lead to permanent vision loss.

Your healthcare provider may prescribe artificial tears or gels to lubricate the eye to alleviate discomfort and protect the cornea from severely drying out. You can also wear patches while you sleep sleeping to keep your eyes moist.

Other treatments depend on the cause of bulging:

• If the cause is an infection, antibiotics are prescribed.
• In the case of Graves' disease, medications to treat that condition may lessen eye bulging over time.
• Corticosteroids, like prednisone, may help control swelling caused by Graves' disease or orbital pseudotumor.

In January 2020, the FDA approved Tepezza (teprotumumab), the first drug approved for thyroid eye disease.

In some cases of bulging eyes, surgery may be a necessary part of treatment. Surgery is indicated when:

• A tumor causes proptosis
• Proptosis is causing double vision
• Lubrication is not sufficiently treating eye dryness

Surgery may also be done for aesthetic reasons. Surgical techniques for treating proptosis continue to improve and provide better aesthetic outcomes than before.

A Word From Verywell

If your eyes have always seemed prominent, it may be completely normal for you. However, if you've noticed one or more of your eyes bulging when they didn't use to, call an eye healthcare provider to ensure there's no underlying cause.