WHAT IS IT?

Thyroid eye disease (TED) is an eye condition related to thyroid disease. Thyroid hormones produced by the thyroid gland in the neck regulate metabolism in the body. Patients with excessive thyroid hormone in the circulation (hyperthyroidism) can develop eye diseases and they may have any of the following symptoms:

  • Neck swelling from an enlarged thyroid gland (goitre)
  • Heat intolerance
  • Sweatiness
  • Increase in appetite and loss of weight
  • Tremors
  • Palpitations
  • Tiredness
  • Anxiety, nervousness and bad temper

Bulging eyes, excessive tearing and pain, dryness, redness and discomfort in the eyes could signal thyroid eye disease. The most significant, but rare, complication of thyroid eye disease is loss of vision due to compression of the optic nerve by swollen tissues around the eye. Swelling of the soft tissues around the eyeball can cause the eyes to bulge outwards and limit one’s ability to close the eyelids.  This exposes the front surface of the eye and causes irritation and damage to the cornea. Patients can also suffer from double vision due to marked swelling and scarring of eye muscles.

WHAT CAUSES TED?

Thyroid eye disease is more common in women and although often associated with hyperthyroidism, may occur in patients with normal or low thyroid hormone levels. Although the exact cause is unclear, what is known is that the body produces antibodies against its own tissues in the orbit.  This sets off a series of biochemical events that lead to swelling of the orbital soft tissues, specifically the eye muscles and orbital fat.

SYMPTOMS

Patients with Thyroid Eye Disease may complain of the following:

  • A “staring” appearance
  • Protrusion of the eye
  • Tearing
  • Eye discomfort and gritty sensation
  • Eye redness
  • Puffy eyelids
  • Double vision
  • Squint
  • Decreased vision

TREATMENT OF TED

Natural Course

It is common for thyroid eye disease to fluctuate within the first one to two years of the disease. Beyond this time, the disease tends to stabilize. Medical therapy (immunosuppression and radiotherapy) are more effective in the active phase of the disease whereas surgical treatment is usually reserved for patients in the inactive phase. It is important for you to be seen and treated by a doctor for the underlying thyroid disease throughout this period. Although the thyroid eye disease tends to improve with good thyroid hormone control, this is not always the case, and consultation with the eye doctor is necessary.

Local Therapy

Tear substitutes and lubricants help to protect the surface of the eye from drying.  Sleeping on extra pillows helps to reduce swelling around the eyes. Double vision can be troublesome if it affects straightforward and down-looking positions (as in reading). Special lenses called prisms may relieve this.

Immunosuppression

Your eye doctor will advise you on treatment for thyroid disease. Steroids are used in selected cases. Taken orally, steroids can cause many side effects when used over a long period of time. These include weight gain, gastric symptoms and bleeding, aggravation of diabetes and high blood pressure and decreased resistance to infection. Where possible, intravenous steroids are given instead. Steroid therapy may also be combined with the use of other immunosuppressive drugs.

Radiation

Radiation is an effective way of reducing swelling of tissue around the eye and relieving compression of the optic nerve. The therapeutic dose used is low and is usually not associated with significant adverse effects.

Surgery

When vision is threatened, early lid or orbital surgery may be necessary. Otherwise surgery is usually reserved for inactive disease. Surgical rehabilitation is usually staged with orbital decompression surgery to reduce excessive protrusion of the eyes, followed by squint and eyelid surgeries to eliminate diplopia and exposure respectively.