Thyroid Eye Disease

Thyroid Eye Disease

Thyroid eye disease (TED) is an autoimmune disease which affects the thyroid gland.

TED symptoms include inflammation and swelling around the eyes and within the eye socket (orbit), watering, bulging of the eyes, and a staring or startled appearance

Eye movements may be reduced due to involvement of the muscles around the eye, causing double vision and in severe cases, the optic nerve can become compressed due to orbital swelling and result in failing vision.

The eye changes usually occur in both eyes but may affect one side more than the other. In most cases, the thyroid gland is also affected by the disease and may become over- or underactive.



What Causes The Changes In The Orbit In Thyroid Eye Disease?

TED is caused by activation of the immune system and the ensuing inflammation of the orbital tissues. The eyes become red and irritated, tissues swell, blood vessels become congested, and eye muscles become inflamed and enlarged and affect the movements of the eyes and may also exert pressure on the optic nerve.


Can The Changes Be Prevented?

Four factors that impact on TED are: age, gender, the degree of activity of the thyroid gland, and cigarette smoking.

Smoking worsens the symptoms of TED by at least a factor of 7. Ask our clinic staff or your family doctor if you want to give up smoking and need help with this.


How Is Thyroid Eye Disease Treated?

Most cases of TED are mild and respond well to treatment. Mild TED can be treated with simple measures such as elevation of the head of the bed to reduce fluid accumulating around the eyes and lubricants for dryness and comfort.

Drugs such as steroids or the use of orbital radiation therapy are used to suppress the immune system where inflammation is severe, especially where there is limitation of eye movements or compression of the optic nerve.

Orbital decompression surgery may be required to prevent permanent loss of vision if the eyesight is impaired due to compression of the optic nerve, or severe exposure of the cornea. The operation involves removal of some of the bony walls of the orbit thus creating space for the tissues and relieving pressure on the optic nerve.

Orbital decompression may also be used to reposition the eyes to a more natural position within the orbits, thereby reducing the bulging appearance. If proptosis (bulging) of the eyes is not prominent, squint surgery may assist with realignment of eye movements and alleviate the double vision.

Eyelid surgery can correct any eyelid malposition caused by scarring within the eyelid tissues.


What Does Orbital Decompression Surgery Involve?

Although the incision is small, orbital decompression is a major procedure. Patients who undergo the operation are admitted to hospital overnight and the operation takes about 1½ to 2 hours for each side.

In an orbital decompression, the bony walls of the orbit are surgically removed, allowing backward movement of the eye within the socket. The operation is performed under general anaesthetic through a small incision at the outer edge of the eyelids and a second incision hidden on the back surface of the lower eyelid. The scar from the skin wound usually fades rapidly into the natural skin creases.

The eye is covered with a dressing for one day post-operatively and a drain is usually left in situ for the first day.

Most patients go home the day following surgery but some may need another day to recover. There is usually mild discomfort for a few days after the operation which is managed with mild pain-relieving medications. There is often swelling around the eyes and double vision but this is usually transient. Most patients are treated with oral antibiotic and steroid medications for 7-10 days after surgery.

If you are taking any medications, please let your surgeon know. If you are taking aspirin or any anti-inflammatory drugs, such as neurofen, this will be discontinued for 3 weeks or so prior to surgery. Dosage of anticoagulant medications, such as warfarin, will also need to be adjusted or stopped temporarily before the surgery.


What Are The Risks And Side Effects Of Orbital Decompression?

Orbital decompression is a major operation and there are significant associated risks and side-effects. Whilst most side effects are temporary and can be treated with medications or surgery, some risks, although rare, may lead to a permanent disability.

The biggest risk is loss of eyesight. However, the occurrence of blindness is less than 1 in 700.

Double vision, which is common immediately after surgery, is due to swelling of tissues around the muscles and settles within a few days or weeks. Occasionally it persists, possibly due to scarring within the muscles themselves. A prism fitted over spectacles can helpful but some patients may need eye-muscle surgery about 6 months after the decompression.

Often with TED, double vision occurs before orbital decompression surgery. However, it can occur for the first time after orbital decompression and can significantly affect ability to work or drive. Preoperative preparations should take this into account.

Most patients develop some numbness of the cheek and upper gum/teeth following the surgery because the nerve which supplies these areas is exposed during the operation. Usually this resolves over a period of months but in a small number of cases, the numbness persists. It does not affect facial movements or appearance.

Less commonly, patients may have problems with sinusitis after orbital decompression surgery. We recommend that patients try to avoid air travel for several weeks, if possible after surgery as disruption of aeration of the paranasal sinuses may increase the risk of severe pain during air travel.

Occasionally, changes to sinus drainage may need to be surgically repaired, particularly if they lead to over-correction of the orbital decompression.

Other rare problems include some weakness in upper or lower eyelid closure, weakness of the eyebrow and asymmetrical correction of the proptosis with one eye set further back, or too low within the orbit.

Finally some major complications including bleeding, leakage of cerebrospinal fluid (the fluid that surrounds the brain) and even death have been noted. Such events are very rare.