What is Thyroid Eye Disease?
The most common cause of orbital disease is thyroid eye disease, which still is an incompletely understood disease. There are many different names you might find for the autoimmune eye condition that is often seen with thyroid disease, including:
- Thyroid Eye Disease, sometimes abbreviated as TED
- Graves’ Opthamolopathy
- Thyroid-associated orbitopathy (TAO)
- Grave’s orbitopathy
Thyroid Eye Disease is an autoimmune eye condition that, while separate from thyroid disease, is often seen in conjunction with Graves’ Disease. The condition, however, is seen in people with no other evidence of thyroid dysfunction, and occasionally in patients who have Hashimoto’s Disease. Most thyroid patients, however, will not develop thyroid eye disease, and if so, only mildly so.
Graves’ eye disease is an eye condition which occurs in about 50% of patients who currently have, or have had, Graves’ hyperthyroidism. However, approximately 10% of patients who have this eye disorder never develop hyperthyroidism. The reasons for the association of hyperthyroidism with the eye disease are not completely understood.
Graves’ eye disease, like Graves’ hyperthyroidism and Hashimoto’s thyroiditis, is an autoimmune disorder. It is caused by the reaction of antibodies and certain white blood cells called lymphocytes, with proteins in eye muscle and the connective tissue and fat around the eyeball. This condition must be distinguished from the mild eye signs of “poppy” eyes and spasm of the eye lids which occur in most hyperthyroid patients due to an effect of excessive thyroid hormones.
Smokers are known to suffer with a more severe form of the disease.
What are the signs and symptoms?
Signs and symptoms include:
- Pain in the eyes, pain when looking up, down or sideways
- Dryness, itching, dry eyes, difficulty wearing contact lenses
- Inflammation and swelling of the eye, and its surrounding tissues
- Swelling in the orbital tissues which causes the eye to be pushed forward — referred to as exophthalmos — which can make Thyroid Eye Disease sufferers appear to have a wide-eyed or bulging stare.
- Bloodshot appearance to eyes
- Double vision (doctors call it diplopia)
- Impaired vision
Thyroid Eye Disease is known to go through varying degrees of severity, and can go into periods of remission as well. When it has been inactive for a period of around a half a year, it’s less likely to recur.
How is this condition managed?
Treatment is aimed at improving the symptoms of orbital involvement. In patients with mild involvement, irritation and foreign body sensation may improve with artificial tears and the use of lubricating ointment at night. If the lids are not closing completely, they may be taped closed at night.
With more severe corneal problems, lid surgery to help partially close the lids or to raise the lower lids may be necessary. In severe retraction of the upper or lower lid, surgery to reduce the effects of the lid retractors, either without or with spacer placement (such as a piece of tissue removed from the roof of the mouth) can help the lids to close. Smoking may worsen symptoms and should be discontinued.
There is no medicine that improves the ability of muscles to move (and thus relieves double vision). It may be possible to optically realign eyes with the use of prisms either applied to glasses or ground into the lens although this may not be effective until things stabilize. When double vision cannot be corrected with prisms, eye muscle surgery may be necessary. In most cases, eye surgeons choose to wait until the double vision is stable. If we operate on a patient who is undergoing progressive change, we may correct them now but have things change within the next few months. It is sometimes not possible to completely remove double vision, but the goal is to remove double vision looking straight ahead and in reading position, as these are the most important directions of sight.
Fortunately, optic nerve problems resulting in decreased vision are uncommon. When it occurs, treatment is aimed at shrinking the muscles, usually by the use of high dose steroids . For those patients who will not tolerate steroids, radiation therapy may be of benefit. If the muscles cannot be made small enough to relieve the compression of the optic nerve (resulting in decreased visual acuity) then the orbit can be made larger. This is usually done surgically by removing one or more of the bony walls of the orbit. This may be done directly (through the soft tissues or skin around the eye). To further reduce the eye bulge, the floor, lateral wall, or even the roof of the orbit may be removed. One of the problems with surgical decompression is that this often affects eye movements, thus changing the pattern of double vision (if it already exists) or potentially producing double vision in those patients who don’t have it before surgery. The same surgery may be advised to rehabilitate the cosmetic appearance of the eyes.
Are there any risks or side effects?
- There may be bruising and swelling around the eye.
- There is a small risk of infection of the eyelid or the eye.
- There is a possibility of under or over correction of the eyelid, which may require further operations.
- There is a possibility of inability to close the eyelids permanently.
- Sometimes, if your other eye has a tendency to droop, it may be more noticeable after this operation. Your eye specialist may warn you of this possibility, where applicable.
What are the Benefits?
- Restoring normal appearance of the eyelid.
- Improved upper part of your vision and improved quality of vision where the pupil was previously occluded by the droopy upper eyelid.