Thyroid Eye Disease
Thyroid Eye Disease (TED) is an autoimmune disease that affects the tissues surrounding the eyes. Although it is most commonly associated with Graves’ disease, it can also occur in people with Hashimoto’s thyroiditis and, less commonly, in people whose thyroid hormone levels are normal.
TED is more than a thyroid problem. It is a disease of the immune system that can affect the muscles, fat, connective tissues, and other structures within the orbit—the space behind and around the eye.
For some patients, the changes are relatively mild. For others, TED can significantly affect vision, comfort, appearance, and emotional well-being.
Normally, the immune system produces antibodies to recognize and defend the body against foreign substances. In autoimmune thyroid disease, however, the immune system mistakenly targets the body’s own tissues.
In Graves’ disease, antibodies involving the thyroid-stimulating hormone receptor (TSHR) play an important role. These immune processes can affect not only the thyroid but also tissues within the orbit.
Inflammation can cause the muscles and fatty tissues behind the eyes to enlarge and swell. Because the bony orbit has limited space, this swelling can push the eyes forward and interfere with normal eye and eyelid movement.
TED can look very different from one patient to another. Symptoms may include:
- Bulging or prominent eyes, known as proptosis or exophthalmos
- Eyelid retraction or a wide-eyed appearance
- Swelling around the eyes
- Redness and irritation
- Dry, gritty, itchy, or uncomfortable eyes
- Pressure or pain behind the eyes
- Pain with eye movement
- Blurred vision
- Double vision
- Difficulty moving the eyes normally
- Changes in facial appearance
In severe cases, inflammation and swelling within the orbit can threaten vision. Any significant decrease in vision, change in color perception, or rapidly worsening symptoms should be evaluated promptly.
TED occurs more frequently in women, although men who develop the disease may experience more severe disease.
Several factors may increase the risk of developing TED or experiencing more severe disease. These include smoking, abnormal thyroid hormone levels, older age, diabetes, elevated cholesterol, radioactive iodine treatment in some patients, and elevated TSH-receptor antibodies.
Smoking is particularly important. Both smoking and exposure to secondhand smoke are associated with an increased risk of TED and more severe or prolonged disease.
Blood testing can help determine whether an autoimmune thyroid disorder is present.
TSH-Receptor Antibodies (TRAb)
TRAb are particularly important in Graves’ disease. These antibodies interact with the thyroid-stimulating hormone receptor and can cause the thyroid to continue producing thyroid hormones even when the body’s normal regulatory system is trying to decrease production.
TRAb levels may also provide useful information when evaluating and managing Graves’ disease.
Thyroid Peroxidase Antibodies (TPOAb)
TPO antibodies are commonly associated with Hashimoto’s thyroiditis but may also be elevated in patients with Graves’ disease.
They are often used to help determine whether hypothyroidism has an autoimmune cause.
Thyroglobulin Antibodies (TgAb)
Thyroglobulin antibodies may be elevated in Hashimoto’s thyroiditis. They are also important in the follow-up of some patients who have been treated for thyroid cancer because they can interfere with the accurate measurement of thyroglobulin.
Not every thyroid antibody needs to be repeatedly measured. The usefulness of repeat testing depends upon the specific antibody and the patient’s underlying thyroid condition.
Early diagnosis is important because TED can progress and, in some patients, cause permanent changes.
Evaluation begins with a detailed medical and thyroid history followed by a comprehensive eye examination.
An eye specialist may evaluate:
- Vision
- Color vision
- Eye pressure
- Eyelid position
- Eye prominence
- Eye movement
- Double vision
- Corneal exposure and dryness
- Signs of inflammation
- Optic nerve function
Blood tests can evaluate thyroid hormone levels and thyroid antibodies.
Imaging with CT or MRI may also be helpful to evaluate the tissues behind the eye, particularly the extraocular muscles and orbital fat. Imaging can be especially useful when the diagnosis is uncertain or when deeper orbital inflammation or optic nerve involvement is suspected.
Oculoplastic surgeons and neuro-ophthalmologists are among the specialists who commonly evaluate TED. Endocrinologists also play an important role in controlling thyroid disease, and optimal care frequently requires collaboration among these specialists.
One of the most important parts of evaluating TED is determining whether the disease is active and inflammatory or has become stable and inactive.
During the active phase, inflammation can cause swelling, redness, discomfort, progressive eye prominence, eyelid changes, and double vision.
Physicians may use a Clinical Activity Score (CAS) along with the examination and imaging findings to help assess inflammatory activity.
Once the inflammatory phase settles, some changes may remain even though the autoimmune activity has become less active. These may include persistent proptosis, eyelid retraction, or double vision.
This distinction matters because treatment is selected according to both the activity and the severity of the disease.
There is no single treatment appropriate for every patient with TED. Treatment depends upon disease activity, severity, symptoms, thyroid status, and whether vision is threatened.
General measures are important for all patients. Thyroid function should be carefully managed, smoking should be stopped, and ocular surface symptoms such as dryness and irritation should be treated.
Patients with active moderate-to-severe disease may require medical therapy to control inflammation and reduce orbital changes.
Traditional treatments have included corticosteroids and, in selected cases, orbital radiation. Newer targeted therapies have significantly expanded the treatment options available for TED.
Targeted Medical Therapy
Research into TED has led to treatments aimed at specific pathways involved in the autoimmune process.
Teprotumumab targets the insulin-like growth factor-1 receptor (IGF-1R) pathway and has been shown to improve several manifestations of moderate-to-severe TED, including proptosis in appropriately selected patients. Other newer drugs on the market that are IGF-1R are Lumvoa. The treatment times and dosage is less and some of the newer data on efficacy is still being established. Both are IV Infusions.
Additional therapies directed at the TSH receptor and other components of the immune response are being investigated, making this a rapidly evolving area of treatment. There are other drugs on the market that we are investigating that are pill form. We can discuss if patients are interested in learning more about the studies.
Because these medications can have important risks and side effects, treatment should be individualized after a careful discussion of potential benefits and risks.
Surgery remains extremely important in the treatment of TED, but is done less commonly than before because of the effectiveness of drugs.
When appropriate, reconstructive treatment generally follows a specific sequence:
- Orbital decompression to create additional space within the orbit and reduce eye prominence when indicated.
- Eye muscle surgery to improve persistent double vision or abnormal eye alignment.
- Eyelid surgery to improve eyelid position, exposure, comfort, and appearance.
Except when urgent intervention is necessary to protect vision, reconstructive surgery is generally considered after the disease has become stable and thyroid function is well controlled.
The physical changes caused by TED can have a profound emotional impact.
Changes in eye prominence, eyelid position, facial expression, and eye alignment may make patients feel that they no longer look like themselves. Double vision and visual discomfort can interfere with reading, driving, working, and normal daily activities.
For this reason, successful treatment of TED should consider not only laboratory values and measurements but also the patient’s comfort, vision, appearance, and quality of life.
TED is a complex autoimmune disease, but our understanding of it has changed dramatically. We now have better methods for determining whether the disease is active, improved imaging techniques, targeted medical treatments, and sophisticated surgical options for restoring function and appearance.
The key is recognizing the disease early and developing an individualized treatment plan.
Patients who have thyroid disease and begin noticing eye prominence, swelling, pressure, redness, double vision, eyelid changes, or changes in vision should consider evaluation by a physician experienced in Thyroid Eye Disease.
With appropriate diagnosis, careful monitoring, and modern treatment, there are more options than ever before to control the disease and address the changes it can cause.