Eye Bulging (Exophthalmos)
Eye bulging — exophthalmos — is a hallmark of thyroid eye disease, an autoimmune condition most often associated with Graves’ disease. Inflammation and swelling behind the eye push the eyeball forward.
It can occur even when thyroid hormone levels are normal, and it may worsen after radioactive iodine if the eye disease is active.
Last medically reviewed: 15 November 2025
Key points
- Eye bulging is a feature of thyroid eye disease, usually linked to Graves’ disease.
- It can occur with normal, overactive or underactive thyroid function.
- Smoking is the biggest modifiable risk factor.
- Sudden vision loss or severe pain needs emergency assessment.
What causes the bulging
In thyroid eye disease, the immune system attacks tissues around the eye, causing inflammation and increased volume of fat and muscle behind the eyeball. This pushes the eye forward and can restrict eye movement.
The condition has an active inflammatory phase and a later stable phase.
Other symptoms
Along with bulging, people may notice dryness, grittiness, redness, sensitivity to light, double vision, or difficulty closing the eyes. In severe cases, pressure on the optic nerve can threaten vision.
Symptoms can be mild and cosmetic or severe and sight-threatening.
Assessment
Assessment includes an eye examination, thyroid function tests, and often TRAb antibody testing. Imaging of the orbits may be arranged in complex cases.
An ophthalmologist or specialist eye clinic is usually involved.
Management
Mild disease is managed with lubricating drops, raised sleeping position and avoiding smoke. More active or severe disease may need steroids, targeted immunosuppressive therapy or radiotherapy. Surgery is reserved for the stable phase.
Keeping thyroid function stable and stopping smoking are central to management.
When to seek urgent medical help
- Sudden loss or blurring of vision.
- Severe eye pain or rapidly worsening double vision.
- Inability to close the eye, with redness or ulceration.
This guidance does not replace emergency services. If you are seriously unwell, seek urgent medical care immediately.
Frequently asked questions
Is eye bulging always due to thyroid disease?
No — other conditions can cause bulging, but thyroid eye disease is a common cause. Assessment is needed to confirm.
Can it occur with normal thyroid tests?
Yes — thyroid eye disease can occur when thyroid hormone levels are normal or well controlled.
Does treating the thyroid fix the eyes?
Controlling thyroid function helps, but eye disease has its own course and may need specific treatment.
Does smoking make it worse?
Yes — smoking is the strongest modifiable risk factor and worsens both the course and treatment outcomes.
References & further reading
This page is based on established medical knowledge and guidelines from authoritative sources. Always consult a qualified clinician for personal medical advice.
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