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Thyroid eye disease (TED) is a rare eye condition characterized by progressive inflammation and damage to the muscles and soft tissues near the eyes, especially the extraocular muscle and connective and fatty tissues.
Thyroid eye disease (TED) is a rare eye condition characterized by progressive inflammation and damage to the muscles and soft tissues near the eyes, especially the extraocular muscle and connective and fatty tissues. TED is also known as thyroid-associated ophthalmopathy (TAO), thyroid orbitopathy, Graves orbitopathy, or Graves ophthalmopathy (GO). The disease often appears suddenly with endocrine and ophthalmic (eyes) symptoms, impairing normal life. TED can cause facial disfigurement affecting the quality of life and daily function of the patient.
What are the signs and symptoms of thyroid eye disease?
Some common signs and symptoms of thyroid eye disease include:
- Red and puffy eyelids, which are more obvious in the morning.
- Irritation and redness of eyes.
- Dry eyes and watering, grittiness, and soreness in the eyes.
- Vision loss due to corneal drying and scarring.
- Bags under the eyes.
- Eyelid retraction (the upper eyelid rises to a higher position making the white part of the eyeball more visible, causing staring eyes).
- Exophthalmos or proptosis (bulging of the eyes).
- Difficulty in closing eyelids.
- Strabismus (the eyes are not in alignment with each other).
- Swelling of soft tissues behind the eyeball.
- Swelling or feeling of fullness in one or both upper eyelids.
- Blurring or dimming of vision due to optic nerve compression.
- Painful orbits (eye sockets).
- Pain in or behind the eye, especially when looking up, down, or sideways.
- Difficulty moving the eyes.
- Diplopia (double vision due to pain or restricted eye movements).
- Discomfort to bright lights.
- Pressure sensation with a headache.
The severity of thyroid eye disease
Most patients have only mild symptoms. However, around 3-5% of patients with thyroid eye disease may have serious problems, including vision loss.
The phases of thyroid eye disease
There are two phases of thyroid eye disease:
- The active stage is the period in which progressive inflammation, swelling, and tissue changes occur. These typically last for about six months to two years.
- The inactive or burnt-out stage is the stable phase when active inflammation settles down and the disease progression stops. In some patients, the eyes return to normal whereas some may have permanent changes (such as double vision and bulging eyes).
What causes thyroid eye disease?
Thyroid eye disease (TED) is caused by an autoimmune process in which the body identifies a part of itself as foreign and reacts to it as it would to any harmful germ.
The immune system attacks both the thyroid and the tissues around the eye. Though TED is seen in all thyroid disorders, it is more often associated with hyperthyroidism or Graves disease.
TED patients produce antibodies that bind to fibroblast cells within the eye socket. This causes the fibroblast cells to produce chemical signals and release biological materials that lead to swelling and congestion in and around the eye socket. This causes inflammation and swelling of the fat and muscle tissues around the eyes, causing bulging of the eyes, retraction of the eyelids, and double vision.
How is thyroid eye disease diagnosed?
Several tests are conducted to assess changes in the tissues around the eyes and vision. They are:
- Thyroid test
- Blood test
- Vision test
- Color test
- Visual field assessment
- Eyelid measurement
- Eye pressure reading
- Sensorimotor evaluation
- Fundus and external photography
- Orbital ultrasonography
- Optical coherence tomography
- Magnetic resonance imaging (MRI) scan
How is thyroid eye disease treated?
Treatment is done to improve the symptoms and protect the eyes while the active stage of thyroid eye disease (TED) runs its course. Treatment options are:
- Discomfort from TED is treated with topical eye lubricants.
- Active inflammation is treated with steroids, corticosteroids, anti-inflammatory medicines, and radiation.
- Dry eyes are managed by using artificial tear eye drops and protecting the eyes in dusty or windy environments.
- Double vision is managed with prisms or occlusion (covering of one eye).
- Hyperthyroid treatment: Optimal thyroid hormone levels are maintained by using oral antithyroid medicine (methimazole, propylthiouracil), radioactive iodine, and surgical thyroidectomy.
- Immunosuppressive medicines: These dampen down the immune system that produces abnormal antibodies.
- Vitamins: Taking selenium to reduce the severity and progression of disease in patients with mild TED.
- Surgery: To avoid damage to the optic nerve and restore the function and appearance of the eye, reconstructive orbital or eyelid surgery may be done. Often several surgeries are required to reverse the changes caused by TED. Surgery is done in three stages:
- Stage I: Orbital decompression surgery to prevent damage to the optic nerve.
- Stage II: Eye muscle surgery to correct misalignment of the eyes and double vision.
- Stage III: Eyelid surgery to adjust retracted lids, improve eyelid closure, and restore eyelid function.
Self-help to reduce the symptoms of TED:
During the active stage of thyroid eye disease (TED), the following self-help suggestions may help reduce symptoms of TED:
Sleeping with eye shields or the head elevated at night reduces the puffiness and congestion around the eyes in the morning.
Stopping smoking because smoking can make TED worse.
Using tinted glasses.
Wearing sunglasses when bright lights are uncomfortable.