What is thyroid eye disease (TED)?
Thyroid eye disease (TED) is an autoimmune disease where your body is treating the tissues around the eye as foreign and attacking them. The eye sits in a bony space called the orbit. The orbit contains fat, nerves and muscles that move the globe. During thyroid eye disease the muscles become larger and the fat is expanded causing the globe to bulge outwards (proptosis, exophthalmos).
TED is the most common cause of orbital inflammation and proptosis in adults, accounting for approximately 40% of all orbital disease. At least 80% of TED is associated with hyperthyroidism or Graves’ disease (GD), one of the most common endocrine abnormalities in the world. Fifty to ninety percent of GD patients develop symptomatic TED. GD and TED affect over 20 million previously healthy and productive adults in the United States alone. The peak incidence is in the fourth and fifth decades but may affect any race and any age.
Although thyroid eye disease occurs most frequently in people with Graves’ disease, it can also occur in people with low thyroid function (hypothyroidism) or with completely normal thyroid function (euthyroidism).
What are the symptoms and signs of TED?
Typical symptoms include blurred or distorted vision, double vision and tearing.
Typical signs include:
- Bulging eyes
- Staring appearance (eyelid retraction) causing more of the white of the eyes (sclera) to show
- Inability to close the eyelids completely (lagophthalmos)
- Misaligned eyes from enlarged, restricted muscles behind the eye
In what ways can TED alter lives?
Blurred or double vision may interfere with driving, reading and computer use. The altered eye appearance and eye symptoms can cause many TED patients to become depressed, withdraw socially, lose self-esteem and suffer job dislocation, divorce and emotional distress. The economic effect of this disease is great because it affects women, and less commonly men, in their peak years of productivity, impacting their families, communities and workplaces.
Are they any conditions that can make TED worse?
Yes. Stabilization typically occurs in the second or third year but may be delayed in:
- Patients over 50 years old
- Cigarette smokers
- Those with a long history of hypothyroidism or poorly controlled thyroid function
What is TSI and why is it tested?
Thyroid stimulating immunoglobulins (TSI) have been found in more than 90% of patients with active Graves’ disease and in 50-90% of euthyroid TED patients.
Patients with active TED often have TSI values three to five times above normal. Higher TSI levels also correlate with eyelid edema, eye muscle enlargement and proptosis. TSI levels drop as TED becomes inactive.
In contrast, laboratory tests to detect thyroid dysfunction, including thyroid stimulating hormone (TSH), thyrotropin, and serum free T3 and T4 levels, do not correlate with TED disease activity.
How is TED treated?
Mild cases can be treated with drops and lubricants to help with dry eye symptoms. Eye inflammation can be treated with steroid eye drops and nasal sprays. More severe cases may require a series of infusions of either steroids or Tepezza, the first and only FDA approved drug for thyroid eye disease.
If proptosis is severe and/or accompanied by optic nerve (the nerve that connects the eye with the brain) damage, surgery may be necessary to restore the position of the eye to its normal position and decompress the nerve . Options include creation of windows in the bone (orbital decompression) or removal of fat behind the eyeball (intraconal fat decompression).
If decreased vision is due to the muscles compressing the optic nerve (compressive optic neuropathy), intravenous corticosteroids often help temporarily. But definitive treatment is orbital decompression.