Thyroid Eye Disease

Thyroid eye disease (TED) is an autoimmune condition that causes inflammation and swelling in the tissues around your eyes. The swelling increases pressure within the eye socket and can push the eyes forward, leading to a bulging appearance known as proptosis. TED most often occurs in people with Graves' disease, which is why it’s frequently called Graves’ eye disease. It can also occasionally occur in people with normal thyroid levels.

Although thyroid autoimmune diseases are lifelong, TED typically has two phases. The active (inflammatory) phase may last two years or longer, during which symptoms can fluctuate. After this, the disease enters a stable phase where inflammation settles, but changes may remain.

Symptoms usually affect both eyes, though one eye may appear worse than the other. They can range from mild irritation to significant vision problems.

Common symptoms include:

• Bulging eyes (proptosis)
• Redness and irritation
• Swollen eyelids
• Dry or watery eyes
• Light sensitivity
• Eye pain or pressure
• Difficulty moving the eyes
• Double vision

In more severe cases, swelling behind the eyes can compress important structures, including the optic nerve, which can threaten vision.

TED develops when the immune system produces antibodies that mistakenly attack tissues containing thyroid hormone receptors. These receptors are found in the thyroid gland and in tissues behind the eyes. When stimulated, they trigger inflammation, causing the eye muscles and fatty tissues to swell. This swelling leads to pressure, discomfort and the visible changes associated with the condition.

Certain factors increase the risk of developing thyroid eye disease:

• Being female (though men often develop more severe disease)
• Taking certain medications
• Undergoing radioiodine therapy for hyperthyroidism
• Smoking (the most significant modifiable risk factor)

Smoking not only increases the likelihood of developing TED but also makes symptoms more severe and longer lasting.

Diagnosis involves a thorough eye examination and blood tests to measure thyroid hormone levels and thyroid-related antibodies. Imaging tests such as CT or MRI scans may be used to evaluate swelling behind the eyes, especially in moderate to severe cases.

Early diagnosis is important because prompt management can reduce the risk of permanent vision or appearance changes.

Treatment depends on the stage and severity of the disease. During the active phase, the goal is to reduce inflammation and relieve symptoms.

Supportive treatments may include:

• Lubricating eye drops for dryness
• Selenium supplements in mild cases
• Prism glasses or patching for double vision
• Medications to control thyroid hormone levels
• Corticosteroids to reduce inflammation

Once the disease becomes stable, surgery may be considered if there are lasting cosmetic or functional concerns. Surgical options can include:

• Orbital decompression surgery to reduce bulging
• Eyelid surgery
• Eye muscle surgery to improve alignment and double vision
• In rare cases, urgent surgery to relieve optic nerve compression

For most people, thyroid eye disease is mild and improves over time. However, some individuals — particularly older adults or smokers — may experience more severe or prolonged symptoms. Even after inflammation settles, some appearance or vision changes may be permanent and require surgical correction.

With early diagnosis, appropriate treatment and coordinated care between endocrinologists and eye specialists, most people are able to manage TED effectively and maintain their quality of life.

Seek immediate medical attention if you notice:

• Sudden worsening of vision
• Loss or narrowing of your visual field
• Changes in colour vision
• Severe eye pain