Thyroid eye disease
What is thyroid eye disease (TED)?
It is an autoimmune eye disease that can occur in some people who have thyroid disease, most commonly in Graves’ disease. There is an abnormal expansion of orbital (eye socket) tissue, particularly the eye muscles and the orbital fat cells.
What causes TED?
It arises because of autoantibodies that form within the blood stream.
How does TED develop?
The circulating autoantibodies are directed towards receptors on the orbital (eye socket) tissue cells. Orbital fibroblasts are activated and cause a cascade of inflammatory activity and swelling of the orbital tissue. The eye muscles which move the eyeball become enlarged, and the orbital soft tissue increase in volume due to abnormal deposition of glycosaminoglycans and fluid accumulation within the orbital tissues.
What are the symptoms?
One may start to experience:
- eye redness
- a staring look (due to eyelid asymmetry/retraction)
If the disease progresses, there may be increased expansion of tissue cells and difficulty in muscle motility. One may not be able to move the eyeball fully in a given direction. They may then experience:
- tightness and pain around the eyeballs.
- bulging (protruding) eyeballs.
- double vision.
- loss of vision (usually over a few days to weeks).
Risk factors include:
- Hyperthyroidism or fluctuating thyroid hormone profile
- Family history
- Cigarette smoke exposure
- Radioactive iodine treatment
What are the Investigations that will be done?
- Thyroid antibody levels – to help us prognosticate (foretell) the disease process.
- Computerised tomography (CT) orbits – demonstrates enlargement of the muscle bellies and the bony arrangement and is particularly useful when planning surgical intervention.
- Magnetic resonance imaging (MRI) – performed to better assess the amount of space at the orbital apex.