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THYROID EYE DISEASE

What is thyroid eye disease?
What causes thyroid eye disease?
Does everyone with an overactive thyroid develop thyroid eye disease?
Are there any other symptoms?
What can be done to prevent thyroid eye disease?
Will my eyes get worse?
Is it important to treat the overactive thyroid condition?
How is thyroid eye disease treated?
What are immunosuppressive drugs?
What is radiotherapy?
What is orbital decompression?
Will my eyes return to normal?

What is thyroid eye disease?

Thyroid eye disease often occurs in people who develop an overactive thyroid gland. Swelling of the muscles and other tissues in the orbits causes the eyes to become pushed forward and more prominent. The eyes often take on a more staring appearance. In more severe cases the swelling may cause stiffness of the muscles which move the eyes. This can cause a "squint" to develop and may result in double vision. Occasionally the swelling behind the eyeball may press on the nerve from the eye to the brain and distrupt vision. Thyroid eye disease is also called thyroid opthalmopathy, Graves’ eye disease or dysthyroid eye disease.

What causes thyroid eye disease?

Most people with thyroid eye disease have or had or will subsequently develop an overactive thyroid gland. In 20% the thyroid eye disease develops in people who do not have an overactive thyroid at the time (may subsequently develop this years later). In 40% thyroid eye disease occurs whilst the thyroid is overactive and in 40% can occur years after the overactive thyroid has been treated successfully.

Overactivity of the thyroid gland is usually caused by an "autoimmune condition" This means that cells which normally protect the body from infection develop a "fault" and begin to recognise the thyroid gland as foreign material and attack it. This stimulates the thyroid gland to produce extra thyroid hormones. The attacking process may spill over to the cells behind the eye causing them to swell. It is not yet known why cells develop the fault that causes them to attack the thyroid gland or why only some patients with overactivity of the thyroid develop thyroid eye disease. Thyroid eye disease does appear to be more common in smokers.

Does everyone with an overactive thyroid develop thyroid eye disease?

No. Severe thyroid eye disease occurs in possibly only 2% with an overactive thyoid. Smoking increases the risk nearly 8 fold. The risk is worse in males, older women and in those with severe overactive thyroid conditions. Mild thyroid eye disease can occur in many more and your specialist will check for this.

Are there any other symptoms?

The commonest symptoms are mild soreness and grittiness of the eyes. Surprisingly one eye is may be more affected than the other. The eyes may become watery uncomfortable and sensitive to light. There may be some puffiness of the upper eyelid or around the eyes. This is often worse in the morning.

What can be done to prevent thyroid eye disease?

Giving up smoking and careful checks of the thyroid blood level may help to prevent eye problems getting worse but despite this other treatment is sometimes required.

Will my eyes get worse?

In most people thyroid eye trouble only causes irritation and puffiness of the eyes. This may continue for a few months or occasionally for 1-2 years and then settles down by itself. In about 1 in 10 patients the eyes get worse. This usually occurs within a few months of the problem starting.

Is it important to treat the overactive thyroid condition?

Yes, this is vital for as long as the thyroid remains overactive, the thyroid eye disease is not likely to settle. Thyroid eye disease ironically can be made worse during the actual treatment of the overactive thyroid and so certain preventative measures are taken to reduce this risk. If radioactive iodine therapy is used then you will be asked to take prednisolone (a steroid) for 3 months after therapy. The specialist will also check your thyoid function regularly so that thyroid replacement hormone medicine can begin as soon as possible to prevent the development of an underactive thyroid brought on by the radioactive iodine.An underactive thyroid might worsen the thyoid eye condition if left unchecked hence the reason for early detection and treatment..

The specialist will also aim to keep your blood TSH level ‘suppressed’ at all times as a rise might again worsen your eye condition. Medical therapy e.g. carbimazole or thyoidectomy can also worsen the eye condition at the outset if the thyoid is very overactive and so once again precautions will be taken to minimise the risk. Thyroid hormone replacement will be prescribed early on to prevent hypothyoidism worsening the eyes.

How is thyroid eye disease treated?

i)Irritation and Redness of the eyes

Artificial tears (hypromellose drops) are often helpful for this problem. These drops are harmless and can be applied as often as required.

ii)Puffiness around the eyes

This is more difficult to treat. Using extra pillows at night may help or sometimes a water tablet (diuretic) may be prescribed for you. The swelling usually improves as the eyes begin to settle down.

iii)Staring eyes

This may settle with time however if the problem is very severe the appearance can be improved by surgery to the eyelids.

iv)Double vision

If this only occurs from time to time then no treatment is necessary. If the double vision begins to interfere with normal activity then specialist activity may be needed. Special glasses with lenses called prisms may be useful and if the double vision remains at a later stage then eye surgery may be considered.

vi)Deteriorating vision

If this occurs quite rapidly specialist treatment with powerful (immunosuppressive) drugs may be needed to damp down the inflammation around the eyes. Alternatively surgery called orbital decompression or radiotherapy treatment may be considered.

What are immunosuppressive drugs?

If the inflammation around the eyes is very severe powerful drugs may be required to damp down the "autoimmune process" which is attacking the eyes. Currently steroid tablets are used in this situation. Steroids are very effective in reducing swelling around the eyes and protecting the eyes from deteriorating vision but may cause weight gain, thinning of the bones and skin and diabetes if continued for a long time at high dosage. Steroids are therefore reserved for more severe cases and used only under specialist supervision. Sometimes a tablet called azathioprine is used in combination with the steroids so that the same degree of treatment can be achieved with a lower dose of steroids. If azathioprine is used regular blood tests will be needed because azathioprine can sometimes reduce the production of blood cells.

What is radiotherapy?

This is given to the tissues behind the eyeball. It involves usually 10 dosages given over 2 weeks. Two thirds of patients find significant benefit but regrettably one third do not and require other therapy such as orbital decompression. Often this therapy is combined with steroids and immunosuppression.

What is orbital decompression?

In severe cases it may be necessary to provide more room in the orbit for the swollen eye muscles by decompression i.e. the removal of some of the surrounding bone. Radiotherapy, steroid and immunosuppression are now replacing the need for this operation for some.

Will my eyes return to normal?

If your eyes are mildly affected they may return to nearly normal. This can take between 12 and 24 months. If your eyes have been more severely affected it is less likely that the changes will go away. In this situation expert treatment is required and carefully planned surgery can be very effective in improving the appearance of the eyes. This may require squint and lid surgery to improve the cosmetic appearance of the eyes. However neither is 100% effective but certainly help greatly to improve the situation.

The British Thyroid Foundation has recently joined Thyroid Federation International, 96 Mack Street, Kingston, Ontario, Canada K7L 1N9.  The website can be found at   http://www.thyroid-fed.org

For further information contact:

Thyroid Eye Disease Association
Solstice
Sea Road
Winchelsea Beach
East Sussex  TN36 4LH
Tel/fax 01797 222338
email: tedassn@eclipse.co.uk
http://www.thyroid.ca/Guides/HG07.html

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NHS Tayside; 2006; version 1.0

Disclaimer; no liability whatsoever is accepted for information given and all such information, especially with regard to drug usage (UK version provided), must be checked with a person’s health provider.