Everything You Need to Know About Thyroid Eye Disease
Thyroid eye disease (TED), also known as Graves’ eye disease or Graves’ ophthalmopathy, is as an autoimmune disease whereby the immune system causes swelling and inflammation of the healthy tissues of the eyes.
Graves’ disease is often associated with hyperthyroidism (overactive thyroid gland), and up to half of individuals with Graves’ disease develops thyroid eye disease. However, thyroid eye disease can also occur in individuals with normal levels of thyroid hormone, and in those with low thyroid hormone levels (hypothyroidism).
The disease may develop in individuals that know they have thyroid disease, but it may be the first sign of Graves’ disease. An important point to note is that while it may occur with other thyroid issues, it is a separate condition. While treating underlying thyroid disease is necessary, it may not relieve eye signs and symptoms.
Causes of Thyroid Eye Disease
The exact cause remains unknown, but it is believed to be caused by an abnormal immune response that affects the healthy eye tissues, leading to eye symptoms including watery, red, and swollen eyes. Different parts of the eyes are affected including the muscle and fat behind the eyes.
Understanding the Signs and Symptoms
Symptoms typically begin within six months of a Graves’ disease diagnosis. However, in rare cases, eye issues may develop a long time after Graves’ disease has been treated. Additionally, some individuals may experience eye symptoms without ever developing hyperthyroidism, and rarely, individuals may have an under active thyroid. Eye symptom severity does not relate to the severity of thyroid disease.
The swelling of muscles, tissues, and fat of the eye socket push the eyeball forward, causing symptoms of thyroid eye disease. In some cases, one eye may be more affected than the other.
Symptoms of thyroid eye disease may include:
- Watery eyes
- Dry, gritty, irritated eyes
- Red eyes
- Bulging eyes with eyelid retraction (gives the appearance of “staring”)
- Puffy eyes
- Sensitivity to light
In cases of advanced stages, additional symptoms may occur, including:
- Difficulty closing the eyes
- Difficulty moving the eyes
- Colors appear dull or washed out
- Blurred vision or loss of vision due to corneal damage or optic nerve compression
- Loss of the ability to close the eye completely, leading to the development of a corneal ulcer
- Blindness (if left untreated)
Who’s at Risk?
Risk factors for thyroid disease include:
- Having Graves’ disease (although as previously mentioned, it can occur with low and normal levels of thyroid hormones)
- Being middle-aged
- Being female
- Having a family history of thyroid eye disease
- Having had radioactive iodine therapy
- Having low levels of selenium in the blood
Diagnosis of Thyroid Eye Disease
A detailed medical history and physical examination will be conducted if an individual presents with eye symptoms consistent with this disease.
Tests including a thyroid function test to measure the level of thyroid hormones, including thyroxine and triiodothyronine, and thyroid stimulating hormones in the blood will be ordered. In individuals with Graves’ disease, thyroxine and/or triiodothyronine will typically be elevated in combination with undetectable thyroid stimulating hormone levels. Additional blood tests may be ordered to determine if thyroid antibodies are present; if they are detected, the individual has autoimmune thyroid disease.
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Additional testing including CT scans and/or MRI scans of the eyes may be ordered to evaluate for tissue swelling behind the eyes. Further, to assess vision and eye tissue changes, various additional tests may be performed including vision and color vision testing, eyelid measurements, visual fields, eye pressure, optic nerve exam, and in some cases, photographs.
If you or your doctor suspects you may have this disease, it is important to be evaluated by an ophthalmologist, as they have specialized training in treating eye diseases. They can evaluate your condition and determine a suitable treatment plan that can help to bring your eyelids back to their normal function and appearance, and they can also monitor for vision changes.
Treatment of Thyroid Eye Disease
The first step of treatment is to get thyroid function under control. Treatment depends on whether thyroid function is overactive or underactive.
Overactive thyroid (hyperthyroidism) is treated with antithyroid medication, typically carbimazole. Underactive thyroid (hypothyroidism) is treated with thyroxine replacement medications.
The active phase of thyroid eye disease lasts between one to three years. If left untreated, the inflammation may damage vision throughout the active phase. In some cases, the changes, such as double vision and eye bulging, might not go away. The goal of treatment is therefore to decrease inflammation and swelling during the active phase of the disease to protect the tissues of the eye and prevent vision loss.
The signs and symptoms should be treated as they appear. Treatment may include the following:
- Artificial liquid teardrops to help lubricate the eyes and minimize eye dryness.
- Cool compresses applied to the eyes to add moisture and decrease inflammation.
- Wearing sunglasses to protect the eyes from sun and wind.
- Ointment, eye pads, and taping the eyelids closed at night can help to protect them and keep the eyes moist.
- Lifting the head at night with an extra pillow or raised headpiece can help to reduce eye swelling.
- Glasses with prisms to control double vision.
- Selenium supplements may help mild cases of thyroid eye disease.
- Quitting smoking and avoiding second-hand smoke.
- Medication including high-dose steroids may be used to decrease eye swelling.
- Radiotherapy to the tissues behind the eyes can also help to decrease swelling but often takes months to see results.
- Intravenous infusion treatment is a newer therapy that is the first FDA-approved medication to treat thyroid eye disease.
These treatments should be continued until inflammation subsides, which can last between one to three years. After this time, the remaining effects of thyroid eye disease are assessed. In cases of advanced thyroid eye disease, surgery is often necessary to return the eyes to their normal function and appearance. Eye surgery may include eyelid surgery and/or eye muscle surgery. In cases where there is the risk of vision loss, decompression surgery may be urgently needed.
Thyroid eye disease causes disturbing eye symptoms including eye redness, inflammation, and swollen eyes, among others. If left untreated, it can lead to blindness. It’s therefore important to discuss any eye changes with your doctor and get a referral to an ophthalmologist if thyroid eye disease is suspected. An ophthalmologist is the most qualified practitioner to evaluate your condition to determine an effective treatment plan to get your eye function and appearance back to normal.