Thyroid Eye Disease

WHAT IS THYROID EYE DISEASE?

Thyroid Eye Disease (TED), is also known as Graves' Ophthalmopathy and Thyroid-associated orbitopathy (TAO). People with hyperthyroidism (overactive thyroid gland) may develop changes around their eyes that include prominent eyes, swelling, infrequent blinking and a staring expression.

WHAT CAUSES THYROID EYE DISEASE?

Thyroid Eye Disease is an autoimmune condition that is generally associated with Graves' disease. Abnormal antibodies are produced that attack the thyroid gland and cause it to become overactive. These antibodies also attack the soft tissues around the eye to cause swelling and inflammation as well as damaging the muscles that move the eyes and the eyelids.

Smokers tend to have a far higher risk of developing thyroid eye disease and the inflammation is generally more difficult to control.

SIGNS AND SYMPTOMS

Eye symptoms may start as soon as the thyroid gland becomes overactive or may develop months or years afterwards. For some, the eye changes may develop before the hyperthyroidism.

• Signs and symptoms include pain or pressure in the eyes, especially, when moving them to look in different directions.
• Wide open staring eyes
• Dryness and grittiness made worse on blinking.
• Redness and swelling of the white part of the eye and the eyelids
• Swelling in the orbital tissues (muscles and fat) that cause the eye to be pushed forward. This is referred to as exophthalmos or proptosis - which can make the sufferer appear to have a wide-eyed or bulging stare.
• Inflammation or scarring of eye muscles may restrict their movement and cause double vision.
• Progressive loss of vision from compression of optic nerve

The active inflammation may last up to 18 - 24 months. After the inflammation subsides many patients are left with puffy lids, proptosis, lid retraction and double vision that may require corrective surgery. In a small percentage (4-8%) of patients the orbital inflammation may be very severe and lead to loss of vision and even blindness, if not treated promptly.

Thyroid eye disease may result in marked disfigurement. The social and psychological impact from this disfigurement rivals the depression seen in severe medical conditions.

TREATMENT

Close coordination between the ophthalmologists and endocrinologist is required to treat TED. A normal thyroid hormone level is essential to the management TED as this helps reduce the severity and duration of orbital inflammation. Oral and IV corticosteroids are the most effective medications available to control the orbital tissue swelling and decrease pressure on the optic nerve and are commonly given for short durations (days to weeks) for this condition.

Patients with mild inflammation may be treated with topical lubricants and non-steroidal anti-inflammatory tablets. When there is more severe inflammation, oral or intravenous cortisone may be required to reduce the inflammation. Radiation therapy may also be needed in certain patients. In very severe cases surgery may be needed to decompress the orbit.

SURGICAL REHABILITATION

Once the inflammation has settled, the function and appearance of the eyes and the eyelids can be improved with reconstructive or rehabilitative surgery of the orbit, extra-ocular muscles and the eyelids.

Surgical rehabilitation is planned in stages. Orbital surgery is performed first, followed by strabismus (squint) surgery, and finally lid surgery. A step may be skipped if not necessary.

Orbital decompression (removal or the bony orbit and orbital fat) may be required to treat bulging of the eyes / proptosis. This allows the eyes to move back to a more normal position.

In TED, there is swelling of the six muscles that move the eye. In the later stages, this is followed by scarring of the muscles. The eye therefore does not move as freely as it should. If there is a mismatch in the movement of the two eyes, double vision will be noticed. In the early stages of the disease steroids can be used to improve the movement of the eyes. Fresnel prisms, which are temporary soft plastic prisms, can be stuck on to glasses to optically correct the double vision. In the later stages surgery to free up the scarred, contracted muscles can be helpful.

Eyelid surgery (blepharoplasty) can help restore the normal appearance of the eyelids by removing excessive fat and skin. Retraction of the lids can also be corrected to improve lid closure and reduce the symptoms of dry eyes.