Proptosis is the forward protrusion of a body part. Doctors typically use it to describe protruding or bulging eyeballs. Proptosis of the eyes can occur alongside swelling, double vision, and less clear vision.

Various conditions can cause proptosis, including thyroid disease, injury, or tumors. Doctors treat proptosis by addressing the underlying condition. For example, if the cause is a tumor, the treatment may be surgery to remove the growth.

With early treatment, the outlook for prognosis is generally positive. However, it depends on what is causing it. Many cases will improve within 2–3 months.

This article discusses the symptoms, causes, diagnosis, and treatment of proptosis.

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Proptosis is a medical term that describes part of the body protruding from its proper location. Although the term can refer to any body part, doctors often use it to describe protruding or bulging eyes.

Another name for this symptom is exophthalmos, which refers specifically to the eyes. Some doctors use these words interchangeably.

Proptosis causes one or both eyes to bulge. Other symptoms can include:

  • diplopia, or double vision
  • ophthalmoplegia, or paralysis of muscles within or surrounding the eye
  • swelling of the eyelid or tissues surrounding the eye socket
  • red eyes due to dilation of surface blood vessels
  • decreased visual acuity, which means a person cannot see as clearly

A person may experience additional symptoms, too, depending on the underlying cause of the proptosis. For instance, if the cause is an overactive thyroid gland, symptoms may include:

  • heat intolerance
  • changes in bowel habits
  • unintentional weight loss
  • a fast or irregular heartbeat

Unexplained weight loss may also suggest the growth of a cyst or tumor.

Various conditions can cause proptosis. In adults, however, the most common is thyroid disease.

An example of this is Graves’ disease, which occurs when the thyroid gland becomes overactive and produces too much thyroid hormone. This is caused by autoantibodies, which bind to orbital soft tissues and generate marked tissue swelling and proptosis.

In children, the most common cause is orbital cellulitis, which is an infection of the eyeball and surrounding tissue. Other potential causes include:

  • inflammation in the orbit from conditions such as:
    • granulomatosis with polyangiitis, which causes inflammation of blood vessels in certain parts of the body
    • sarcoidosis, which is a condition that causes the growth of granulomas
  • interference with the return of venous blood from the eye socket, such as:
    • carotid-cavernous fistula, which is an atypical connection between an artery and vein
    • orbital varices, or malformation of the veins
    • cavernous sinus thrombosis, which is a blood clot in the sinuses
  • a growth that invades the eye socket, such as a tumor caused by:
    • leukemia
    • lymphoma
    • capillary hemangioma
    • cavernous hemangioma
  • other growths in the eye socket, such as a lacrimal gland tumor or dermoid cyst
  • forced entry of foreign matter into the socket

Doctors base a proptosis diagnosis on an eye examination and medical history. They will also look for the underlying cause, such as Graves’ disease or cancer. This process may involve:

  • blood tests for:
    • thyroid function
    • complete blood cell count
    • kidney function
    • autoimmune antibodies
    • C-reactive protein, which is a marker of inflammation
  • blood cultures and nasal swabs to detect infections
  • imaging tests, including:

Treatment for proptosis involves treating the underlying cause. In some cases, this requires cooperation between several medical professionals, such as:

  • a primary care doctor
  • an ophthalmologist, or eye doctor
  • an endocrinologist

Treatment may be surgical or nonsurgical.

Nonsurgical treatment

Depending on the underlying cause, nonsurgical treatment may involve:

  • reducing dryness with eye lubricants
  • wearing sunglasses to prevent glare and sensitivity to light
  • quitting smoking
  • botulinum toxin (Botox) injection to correct an unusually high position of the upper eyelid
  • corticosteroids to reduce inflammation
  • chemotherapy to reduce tumor size

In 2020, the Food and Drug Administration (FDA) approved the drug teprotumumab (Terpezza) for the treatment of proptosis due to Graves’ disease. It helps block inflammation and has the potential to spare people with the condition the need for multiple surgeries.

Surgical treatment

Surgical treatment may include the removal of tissue or a tumor.

If a person does not respond to medications, orbital decompression and extraocular muscle repair may be necessary to correct vision.

Orbital decompression is the removal of bone and fat from the orbit, while extraocular muscle repair is the surgical correction of the muscles that control eyeball movements.

This depends on the underlying condition and the person’s response to treatment. If the cause is unrelated to thyroid disease, the redness, pain, and swelling should improve significantly after 2–3 months.

In contrast, if the cause stems from thyroid disease, recovery may take much longer. Some individuals may not experience a total improvement, as 5% of people who experience thyroid-related thyroid disease have permanent double vision or vision impairment.

People with thyroid-related proptosis can prevent it from getting worse by taking their prescribed medications. Quitting smoking is also important, as this can prevent the progression of thyroid eye disease.

Proptosis changes a person’s appearance, which can affect their emotional well-being and quality of life. If the condition causes a vision impairment that does not improve, proptosis may also result in a level of disability.

But support is available for people living with proptosis. Those who find that proptosis affects their self-image or who are adapting to changes in eyesight may find it helpful to join a support group. The Graves’ Disease & Thyroid Foundation provides one for those with thyroid disease, for example.

Another option for people with vision changes is speaking with an occupational therapist, who can provide help and insight on adaptive tools people can use to continue doing their typical activities.

People who experience anxiety, low self-esteem, or a persistent low mood may benefit from speaking with a mental health professional.

Proptosis is a medical term for a body part protruding from its location. Proptosis of the eyes, or exophthalmos, is when one or both eyes protrude forwards from their socket. This can occur alongside changes in vision, inflammation or swelling, and more systemic symptoms, depending on what is causing it.

Although Graves’ disease is the most common cause of proptosis in adults, an array of other conditions may also cause it. Diagnosis requires an eye examination, as well as an investigation into what is causing the eyes to bulge.

Treatment depends on the cause and severity of the condition. In many cases, early treatment results in a positive outlook, with most people experiencing an improvement in their proptosis in a few months.