Thyroid Eye Disease

The thyroid gland is located in the neck and is involved in controlling metabolism. It can lose normal regulation such that the gland can become over active - "hyperthyroidism" or under active "hypothyroidism". Thyroid eye disease TED (also known as thyroid orbitopathy) is an autoimmune condition, the exact cause being unknown. It tends to occur in people with an over active thyroid in a condition known as Graves disease. More unusually it can occur when the thyroid is under active or even when the thyroid gland appears to be working normally.

Thyroid eye disease is relatively uncommon, with an incidence of approximately 10 cases for every 100,000 people per year. There is a female preponderance of 4:1 which is probably a reflection of the higher incidence of hyperthyroidism in women. The usual age of onset is between 30 and 50 years. Smoking is an important risk factor.

The course of TED usually involves an active inflammatory phase, where there is deterioration, for a few months. The disease then "peaks" before starting to improve, often spontaneously. It ends with a "burnt out" phase where further damaging changes are unlikely. The importance of realising the natural history of the condition lies in deciding on the treatment options. Generally medical treatments, such as oral or intravenous steroids, are used in the acute inflammatory phase to try and shorten this period and limit tissue damage. Once the inflammation has subsided and the inactive "burnt out" phase entered then surgery can be helpful.

The Thyroid Eye Disease Charitable Trust (TEDct) aims to provide information, care and support to those affected by thyroid eye disease.

Signs of Thyroid Eye Disease

Presentation of this condition can be extremely variable but symptoms can include:

• Red eyes and ocular irritation
• Ache behind the eyes (often worse in the morning)
• Puffy eyelids
• Bulgy or prominent eyes (proptosis)
• Double vision (diplopia)

A relatively small number of people (less than 5%) with TED can get reduced vision secondary to pressure on the optic nerve at the back of the eye. This is known as "compressive optic neuropathy" and requires urgent medical and/or surgical treatment.

Diagnosing Thyroid Eye Disease

TED can be quite subtle and difficult to diagnose or quite obvious in more severe cases. The diagnosis is chiefly based on the clinical examination but blood tests and imaging eg Magnetic Resonance Imaging (MRI) scan can be very helpful, the latter often demonstrating typical changes of TED in the eye muscles and socket. Patients with suspected or diagnosed with TED will need an assessment with an endocrinologist (physician who specialises in diabetes, thyroid and pituitary abnormalities) if they have not already been reviewed.

Orbital MRI scan showing typical appearance of thickened eye muscles (red arrow points to thickened inferior rectus muscle)

Treatment of Thyroid Eye Disease

The treatment of this condition varies considerably depending on the level of activity in the acute phase. All patients with an over or under active thyroid gland need systemic treatment to get back to normal thyroid levels as soon as possible. Smoking should be stopped, with support if required.

Sore, red eyes can be helped by the use of artificial tear lubricants, usually drops during the day and ointment at night. Medical anti-inflammatory treatments, such as oral or intravenous steroids, may be recommended in the acute phase and orbital radiotherapy also plays a useful role in certain circumstances. Surgery is only required in a proportion of patients once the disease has "burnt out" and broadly can be grouped in order as follows:

Orbital decompression

This involves creating a defect in the bony eye orbit to create more tissue space and allow a prominent eye to retract back into the socket.

Squint surgery

This is required in patients who are left with double vision and involves tightening or weakening eye muscles to allow the eyes to work together more effectively.

Eyelid surgery

Useful eyelid procedures to improve function and/or cosmesis include lowering the upper eyelids, elevating the lower eyelids and reducing "heavy" upper lids (see Upper Lid Blepharoplasty) or lower lid "eyebags" (see Lower Lid Blepharoplasty).