An Overview of Proptosis

Woman with eye pain
Eric Audras

Proptosis, also known as exophthalmos, is a bulging of one or both of the eyes. While 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.

Symptoms

The main symptom of proptosis is an abnormal protrusion 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. Other symptoms that can accompany bulging eyes include the following:

  • 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 result from a sinus infection that has spread into the orbit, creating an abscess. Unilateral proptosis can also be caused by trauma, inflammation, arterio-venus malformations, orbital tumors, and cancer. Glaucoma that is 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 if it's in only one eye, medical testing should be done right away, as 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 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 doctor will start by taking your medical history and doing a physical exam. He or she will also ask you:

  • How long the bulging has been present
  • Whether the bulging seems to be getting worse
  • Whether 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 inability to tolerate heat, increased sweating, involuntary shaking movements (tremors), anxiety, increased appetite, diarrhea, palpitations, and weight loss. (These are common symptoms of Graves disease.)

Your doctor will examine your eyes for redness, sores, and irritation using a slit lamp—an instrument that enables a doctor to examine the eye under high magnification. If your eyelids move as fast as your eyeballs when you look down, or you appear to be staring, it could indicate Graves disease.

Your doctor may also measure the degree of bulging with a ruler or a special instrument called an exophthalmometer. If measurements are outside of normal ranges, more testing may be done, especially if the bulging only affects one eye. Tests may include an MRI, bloodwork, an ultrasound, or even a biopsy.

Treatment

One of the main symptoms 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 not only uncomfortable, but can also cause scarring which could lead to permanent vision loss. Artificial tears or gels to lubricate the eye may be prescribed to alleviate discomfort and protect the cornea from severely drying out. Patches may also be worn at night while sleeping to keep the eyes moist.

Other treatments depend on the cause of bulging. If the cause is an infection, antibiotics are given. In the case of Graves disease, medications to treat that condition may, over time, lessen bulging of the eyes. Corticosteroids such as prednisone may help control swelling due to Graves disease or orbital pseudotumor.

When proptosis is caused by a tumor, is causing double vision, or if lubrication is not sufficiently treating dryness of the eye, surgery is indicated. Surgery may also be done for aesthetic reasons. Surgical techniques for treating proptosis continue to improve, according to one study, and are providing better aesthetic outcomes than they used to.

A Word From Verywell

If your eyes have always seemed prominent, it may be completely normal for you. If you've noticed one or more of your eyes bulging when they didn't used to, however, it's important to call an eye doctor to be sure there is not an underlying cause.

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