Thyroid eye disease (TED) is an autoimmune disease characterized by the inflammation of muscles, fat, and other tissues around and behind the eyes. This inflammation can cause the eyes to bulge (or protrude), as well as a number of other symptoms, including puffy eyelids, eye redness and irritation, eye pain, double vision, and eyelid retraction (when the upper and/or lower eyelids are pulled back more than normal). In severe cases, TED can cause vision loss and facial disfigurement.

TED is more common in women than men, though men are more likely to have more severe eye disease. The condition can affect people of any age, though it typically occurs in those between ages 30 and 50, and it is less common in children. TED most frequently affects people with Graves' disease, an autoimmune disorder that can cause hyperthyroidism (overactive thyroid), when the thyroid gland produces too much thyroid hormone. Less commonly, it occurs in people with hypothyroidism (underactive thyroid) or in those with normal thyroid levels.

Various treatments are available for people with TED, including eye drops, lifestyle changes, medications, radiation therapy, and surgery.

TED is a condition that causes inflammation and swelling of tissues in and around the eye, including fat, connective tissues, and the extraocular muscles (muscles that control the movement of the eyes and eyelids).

The disease typically involves an initial active phase followed by an inactive phase.

In the active phase, tissues around the eye become inflamed, enlarged, and damaged. The damage may be permanent but can be alleviated with different treatment options. During this phase, symptoms (which may include dry eyes, bulging eyes, eyelid retraction, and double vision) typically worsen as inflammation progresses. In severe cases, which are rare, enlarged tissues can compress the optic nerve—the nerve that connects the back of the eye to the brain—resulting in vision loss. In some cases, TED leads to changes in facial appearance, such as eyelid retraction and bulging eyes that may be treated with surgery. The duration of the active phase can vary substantially, though it often lasts for one to three years, ultimately transitioning to an inactive phase.

In the inactive phase, inflammation stabilizes, and disease progression stops. Some symptoms, such as eye redness, may resolve, but tissue damage and scarring—as well as certain symptoms, such as bulging eyes and double vision—can remain.

TED is a relatively rare condition, affecting between 90 and 300 individuals out of every 100,000. It typically occurs in people with an autoimmune thyroid disorder, most commonly those with hyperthyroidism caused by Graves’ disease, though it less frequently affects individuals with thyroid cancer or autoimmune thyroiditis (also known as Hashimoto thyroiditis) who have hypothyroidism or even normal thyroid levels.

TED is also known by several other names, including Graves’ ophthalmopathy, Graves’ orbitopathy, thyroid-associated ophthalmopathy, and thyroid-associated orbitopathy.

The exact causes of TED are not yet completely understood.

TED is an autoimmune condition, meaning the body’s immune system mistakenly attacks healthy tissues—in particular muscles and fat—behind the eyes, resulting in tissue inflammation and enlargement.

The inflammation and enlargement can cause the eyelid to bulge. It also causes fibrosis (scarring) of the extraocular muscles, which restricts their movement. The inflammation and enlargement also lay down cement-like tissue in the eyelids, causing eyelid retraction, fatty hypertrophy (enlargement of fat tissue) in the upper and lower eyelids leading to a puffy eye appearance.

Certain factors may increase the risk of developing TED, including:

• Being female
• Smoking
• Graves’ disease (TED affects 25% to 50% of people with Graves’ disease)
• Uncontrolled abnormal thyroid levels
• Radioiodine (radioactive iodine) therapy, which may be used to treat Graves’ disease

Symptoms of thyroid eye disease may include:

• Bulging of the eye (known as proptosis or exophthalmos)
• Gritty, dry sensation in the eye
• Red or irritated eye
• Double vision
• Blurring of vision
• Puffy eyelids
• Eyelid retraction
• Deep pain or pressure in the eye socket that can worsen with eye movement
• Difficulty moving the eye in certain directions
• Strabismus (when the eyes are misaligned)
• Changes in color vision (colors appear less bright than usual)
• Vision loss (in severe but rare cases)

In most cases, symptoms of TED occur in both eyes, though often they are more pronounced in one eye than the other.

To diagnose TED, your oculoplastic surgeon will review your medical history and labs, conduct an exam, and may order one or more tests.

Your doctor will ask you about your symptoms, including when they began, as well as any risk factors for TED that you might have, such as whether you have an autoimmune disease or if you smoke. Your doctor will closely examine your eyes, eyelids, and the area around your eyes to check for signs of TED, including inflammation, fullness, and redness. The doctor will assess the range of motion of your eyes and may test your visual acuity and color vision using reading tests and color charts, respectively. As part of the eye exam, your doctor may measure the degree of eye bulging using an exophthalmometer, a device used to measure the degree of eye protrusion.

Your doctor may order additional tests to make a diagnosis, including:

• Imaging tests, which may be used for people with moderate to severe disease. Imaging tests may include a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan, allowing the doctor to visually assess the risk of compression of the optic nerve, as well as other tissues around the eyes.
• Blood tests, which may include TSI (thyroid stimulating immunoglobin) test to measure the level of TSI in the blood. TSI is an antibody that signals the thyroid to produce and release excess thyroid hormones. Other tests help evaluate thyroid function and may include thyroid-stimulating (TSH) and tests for the thyroid hormones thyroxine (T4) and triiodothyronine (T3).

Treatment for TED may include:

Lifestyle changes and at-home treatments:

• Quit smoking.
• Use lubricating eye drops (also known as artificial tears), lubricating gels, and ointments. These over-the-counter treatments can help reduce irritation and dry eye symptoms. These can be purchased over the counter. (Lubricating eye drops lubricate and moisturize the eyes. They are different from redness-relieving eye drops, which are not recommended for dry eyes.)
• Wear an eye patch. Wearing a patch over one eye can relieve double vision.
• Wear sunglasses. Sunglasses can help people with light sensitivity.

Other treatments, including medication and surgery:

• Reversing thyroid dysfunction. For patients with thyroid dysfunction, treatment can help correct thyroid hormone levels to within the normal range. Treatment may involve medications or surgery to remove the entire thyroid or part of it.
• Prism eyeglasses. The lenses of prism glasses contain a prism. They are used to correct double vision.
• Teprotumumab. Sold under the brand name Tepezza®, teprotumumab was approved by the Food and Drug Administration (FDA) in 2020 for the treatment of adults with TED. It is a monoclonal antibody that works by blocking the action of insulin-like growth factor-1 receptor (IGF-1R), a protein involved in TED. Tepezza is administered by infusion.
• Glucocorticoids (steroids). Glucocorticoids, such as oral prednisone and IV (intravenous) methylprednisolone, can help reduce inflammation. Glucocorticoids are usually reserved for people with moderate to severe active TED.
• Radiation therapy. Radiation therapy may be used to kill cells that contribute to inflammation around the eye.
• Surgery. Different surgical procedures may be used to treat TED, including:
  • Orbital decompression surgery, a procedure in which a surgeon removes some of the bone that makes up the eye socket, with the aim of increasing the space available for inflamed and enlarged muscles and other tissues. The surgeon may also remove fat from the eye socket (known as fat decompression surgery).
  • Strabismus surgery, a procedure on the eye muscles to align the eyes.
  • Eyelid surgery, to treat eyelid retraction and puffiness around the eyes.

Some people may need more than one of the surgical procedures listed above.

The outlook for people with TED varies based on numerous factors, including the severity of the condition and the timing of diagnosis and treatment. In general, the outlook is favorable, though it tends to be better for people with mild TED who are diagnosed and receive treatment early in the course of the disease.

TED can lead to vision loss, though it does not occur in most cases. Most people with TED can be treated with nonsurgical treatments, though around 20% of cases require surgical intervention. People with TED should continue to follow up with their doctor for ongoing monitoring of the condition.

“Thyroid eye disease exists on a spectrum,” says Michelle M. Maeng, MD, a Yale Medicine oculoplastic surgeon. “At Yale, we recognize that no two patients are alike. We offer a cutting-edge, multidisciplinary approach to thyroid eye disease, integrating expertise from oculoplastic surgeons, endocrinologists, strabismus surgeons, oncologists, and others to provide personalized, comprehensive care using the latest advancements in medical treatments and surgical procedures.”