The thyroid is a gland in the neck located just below the “Adam’s apple.” It produces hormones that regulate body temperature and metabolism, the chemical process by which the body turns food into energy. Thyroid hormones also assist other organs in their function.
Patients who have abnormalities of the thyroid gland may develop thyroid eye disease, or TED, a condition that causes swelling around the eyes. This happens most commonly in patients with Graves’ disease (hyperthyroidism), although it can happen to people with any thyroid abnormality. Such swelling can cause changes in eyelid or eye socket position, which can affect appearance and/or vision.
The most common symptoms associated with thyroid eye disease include irritated or dry eyes, or redness of the eyes. These symptoms can result from the increased evaporation of tears caused by shifts in the muscles around the eye, including upper or lower eyelid swelling or puffiness, or eyelid retraction (eyelids that are higher than normal). Sometimes this shift in eyelid position causes changes in appearance, such as a “surprised” look or a “stare.” One or both eye may bulge forward from swelling of fat or muscle behind the eye. Excessive tear evaporation can produce dry spots on the cornea (surface of the eye) that result in blurred vision. In severe cases, infection may develop.
Women are six times more likely to than men to develop any sort of thyroid disease. Of all people with thyroid disease, about 30 percent develop thyroid eye disease. Unfortunately, there is no specific blood or diagnostic test that can predict the onset of the disease in patients who have Graves’ disease. Smoking increases the risk of developing TED and increases the risk of developing a more severe form of the disease.
Thyroid eye disease is treated primarily by two specialists: an endocrinologist/primary care doctor and an ophthalmic plastic surgeon. Together, these two specialists coordinate care for optimal management of thyroid hormone levels and the eye condition. Occasionally, some patients may require the expertise of additional specialists, including otolaryngologists, strabismus surgeons, thyroid gland surgeons, and radiation specialists.
Thyroid Eye Disease, thyroid-associated orbitopathy, thyroid ophthalmopathy, Graves’ orbitopathy, and Graves’ eye disease are all different names for the same condition.
Graves’ disease is an autoimmune condition in which the body’s immune defense system creates an abnormal protein that over-stimulates the thyroid gland, raising thyroid hormone levels in the bloodstream [hyperthyroidism]. The symptoms of Graves’ disease can include weight loss, heart palpitations, flushing, heat intolerance, sweating, insomnia, restlessness, and abnormal fine hair growth. Graves’ disease is not caused by environmental factors, medications, infections, or cancer.
The abnormal protein that activates the thyroid gland in Graves’ disease also activates cells of the eye socket (orbit). Once activated, these cells produce substances that cause eyelid and eye socket tissue to swell. This abnormal swelling is what causes the eye changes associated with thyroid eye disease (TED).
Although Graves’ disease and TED share a common autoimmune disease abnormality, their disease courses do not always progress in parallel. That is, some patients with well-controlled thyroid hormone levels may develop continued and severe eye disease, while some patients with long-standing abnormal thyroid hormone levels may never develop eye disease. How these two conditions are linked is still being investigated.
Unfortunately, there is no specific test or diagnostic method that can predict the onset of TED. Approximately 30 percent of patients with Graves’ disease develop some sort of eye abnormality. Generally speaking, patients diagnosed with TED will develop eye changes within 18 months before or after diagnosis. Sometimes, eye changes can happen many years after developing thyroid abnormalities.
Yes. In some cases, patients with either low thyroid hormone levels [hypothyroidism], or normal hormone levels [euthyroid] can develop thyroid eye disease. However, most patients that develop TED have abnormally high levels of thyroid hormone [hyperthyroidism], which is most commonly due to Graves’ disease.
Thyroid eye disease may be associated with four general categories of problems: eyelid changes, prominence of the eyes (bulging), double vision, and optic neuropathy (vision loss). A patient may develop any combination of these problems. Very few patients develop all of these changes. Asymmetry—with one eye affected more than the other—is typical. Each of these changes is explained in more detail below.
Eyelid changes are the most common thyroid eye disease abnormality. The upper and lower eyelids and/or eyebrows may become swollen or puffy, a condition that may fluctuate, but typically persists the entire day. Eyelid retraction, or an abnormally large opening of the eyelids, may also develop. Any change that keeps the eyes open too wide, or impairs eyelid closure or blink, can cause mild and occasional eye dryness. Severe cases of dryness can lead to corneal damage.
Prominence (bulging) of the eyes
Prominence of the eyes, also known as proptosis or exophthalmos, is caused by swollen muscle or fat tissue in the eye socket pushing the eye forward. This can alter a person’s appearance, producing a wide-eyed or bulging stare. One or both eyes may be affected, and it can happen with or without eyelid changes.
Double vision occurs if the eyes are not perfectly aligned and do not see the same exact image. Six small muscles within the eye socket control each eye’s movement. The thickening or swelling of those muscles can cause the eyes to move out of alignment, resulting in double vision.
This is the most severe form of thyroid eye disease, affects the optic nerve and can compromise vision. The optic nerve travels within the eye socket and transmits all visual information from the eye to the brain. Severe swelling of the muscle and fat tissue within the eye orbit can squeeze the optic nerve, causing vision to deteriorate. This may be temporary or permanent, depending on the severity and duration of pressure on the nerve.
Vision can be affected in several ways by thyroid orbitopathy. The most common eye finding in this condition is dry eyes. Dry eyes can cause irritation as well as slightly blurry vision. If the muscles that move the eyes become enlarged from inflammation due to thyroid eye disease, double vision can result. This is a very frustrating problem and may be treated with a variety of medical or surgical options.
A small percentage of patients appear to have thyroid eye disease based on their examination and appearance, yet have normal blood tests. This is known as the euthyroid form of thyroid eye disease. As blood testing continues, thyroid level abnormalities sometimes develop. Other patients will always have normal thyroid levels. What causes this phenomenon is unknown.
Your ophthalmologist leads a team that includes fellow ophthalmologists and technicians. They take a complete history and thoroughly examine your eyes. Sometimes CAT scans and blood tests are needed to establish the diagnosis.
In addition to giving you a complete eye exam, your ophthalmologist will perform a set of measurements to assess your vision, the condition of your pupils and eye sockets, as well as any movement of the eyes and eyelids. Subsequent eye examinations may include dilation of the pupils and visual field (peripheral vision) tests. If you have any CAT scans or MRI scans of your eye sockets or head, please bring them to your appointment. Your physician may order additional CAT or MRI scans, and additional blood tests. Correct diagnosis and the development of a treatment plan require a great deal of information, so your initial visit may take up three or more hours.
Treatment will depend on exactly how thyroid eye disease has affected your eyes. Eye dryness is typically treated with lubricating eye drops and ointments. Abnormal eyelid positions, bulging eyes, and optic neuropathy are typically treated with a combination of medications and surgery.
Close follow-up with your primary care doctor or endocrinologist is essential to properly treat, monitor, and manage your thyroid hormone status. Lubricating eye drops and ointments can be used to treat eye dryness symptoms. Patients with more severe disease may require steroids in pill or intravenous (IV) form, depending on their condition. Unfortunately, eye drop medications can only alleviate symptoms but cannot fully resolve thyroid eye disease.
Vision loss is the most serious reason why a patient will undergo surgery. This may be due to optic neuropathy or an eyelid abnormality causing severe exposure damage to the eyes. Patients who have double vision may proceed with eye muscle (strabismus) surgery to correct eye alignment. Some patients elect to proceed with surgery if they have eye dryness or irritation symptoms. Finally, because Thyroid Eye Disease can alter a person’s appearance, some patients elect to undergo ophthalmic plastic surgery to restore their appearance.
Your doctor will discuss with you all appropriate treatment options, including surgery. Most patients with thyroid eye disease do not require surgery. If surgical treatment is necessary, your surgeon will discuss its effect on the disease, as well as possible benefits, risks, and alternatives to surgical intervention.
There are three primary forms of surgical treatment for thyroid eye disease: 1. orbital decompression, 2. eye muscle (strabismus) surgery, and 3. eyelid surgery. Each procedure can affect other parts of the eye socket, eye muscles, or eyelids. Not all patients require all three types of surgery. However, if surgical treatment is needed, the procedures must be performed in the specific order listed above to achieve the best possible results.
The eye socket has four bony walls around it. Orbital decompression involves removing some of the bone of these walls to expand the size of the eye socket to accommodate swollen muscles and fat. This alleviates pressure on the optic nerve, and reduces proptosis by allowing the eyeball to move back to a more normal position. A team of highly specialized ophthalmologists, as well as otolaryngologists and other specialists, performs this surgery. Each procedure requires general anesthesia and a post-surgical hospital stay. If surgery is necessary, your ophthalmologist will discuss the details with you.
Strabismus (eye muscle) surgery
This specialized surgical procedure adjusts the position of the eye muscles to treat double vision. Your ophthalmic plastic surgeon will refer you to a surgical specialist who performs the procedure and provide follow-up care.
The eyelid position can be adjusted with surgical treatment. Surgery to lower the upper eyelids or raise the lower eyelids is performed on an outpatient basis. The surgery improves the height and contour of the eyelid to reduce dryness and corneal exposure, and improves eyelid appearance.
Rarely, your surgeon may recommend other treatments, such as radiation therapy, if there is vision loss.
Even though your doctor said you could benefit from surgery, a six-month period of eye stability—in which there are no active changes in your eyelids, proptosis (bulging), or eye muscle position— is necessary before surgery to ensure the best possible outcome. If surgery is not preceded by six months of such stability, the final surgical outcome is unpredictable.
Close follow-up with your endocrinologist or primary care doctor to monitor your thyroid hormone levels is crucial to ensuring the best management of thyroid eye disease.
YES! This is perhaps the single most important step you can take to minimize thyroid eye disease. Multiple research studies have shown that smoking is a severe risk factor in the development and progression of thyroid eye disease, although the exact causal relationship is unclear. Please talk to your primary care doctor for tips, support groups, and medications that can help you stop smoking. This not only minimizes your risk of thyroid eye disease, but can improve your health in many other ways.
Yes. We host a thyroid eye disease support group here at Mass. Eye and Ear. This is a joint effort with Massachusetts General Hospital and the Graves’ Disease & Thyroid Foundation. Please contact us for meeting information: call 877-643-3123 or email email@example.com.