Thyroid Eye Disease

TED can be classified into two types.

1. Type I TED: It is characterised by mild inflammation around the eyes, stiffness of the eye muscles, and limited eye movement (myopathy).
   
   
2. Type II TED: It is characterised by severe inflammation around the eyes and eye muscle stiffness leading to limited movement of the eyes (myopathy).

When a person has GD, their body's immune system produces certain abnormal proteins, known as antibodies, that cause the thyroid gland to produce too much thyroid hormone. The antibodies mistakenly attack the eye and surrounding tissues, leading to inflammation and TED. However, not everyone with TED has the same immune system issues, so there might be other reasons why some people get this condition.

The reason why some people develop TED is not completely clear. However, there are some factors known to increase the chance of a person developing this disease called ‘risk factors’. Having a risk factor does not mean you will definitely get the disease, but the more risk factors you have can make it more likely. Some risk factors for TED are:

• Family history of GD
• Presence of other autoimmune diseases such as autoimmune gastritis, Hashimoto’s thyroiditis, type 1 diabetes, vitiligo, rheumatoid arthritis, etc.
• Smoking or exposure to second-hand smoke
• Women are likely to be at a higher risk than men
• Persons below 40 years of age
• Having received radioactive iodine treatment in the past
• Stress
• Uncontrolled thyroid disease

If your doctor thinks that you might have TED, they will ask you about your symptoms and medical history, conduct a physical exam, and run certain tests that include:

• Complete eye examination: This may include measurement of the degree of bulging of the eyes (proptosis) using a device called an exophthalmometer.
• Routine vision tests: These tests are done to check how well someone can see clearly (visual acuity).
• Clinical activity test: The clinical activity of TED is measured using 7-point criteria such as pain associated with eye movement, redness and swelling of the eyelids and/or conjunctiva (thin, transparent covering of the eye), range of eye movements, vision, and severity of eye protrusion. A score of 3 or more suggests active disease.
• Computed tomography (CT) scan: In more severe cases, a CT scan of the eye and surrounding tissues is useful to check if the eye muscles are pressing on the eye (optic) nerve due to inflammation.
• Thyroid Function Tests: These tests help in diagnosing GD, hypothyroidism, or hyperthyroidism by measuring the levels of thyroid hormones or thyroid antibodies in the blood.

TED can be broadly divided into two stages:

1. Active stage: You may suffer active eye inflammation and swelling and infection during the active phase which can last from months to years. The severity of symptoms can change over time.
   
   
2. Chronic stage: The symptoms stabilize during the chronic phase. However, the physical changes to the eyes and eyelids may continue to occur.

The main goal of managing TED is to achieve normal thyroid function by treating the underlying cause of this condition. However, in persons with GD, treating hyperthyroidism may not always improve the symptoms of TED.

Medications:

• Selenium supplements: They can improve the quality of life, reduce inflammation, and slow the progression of TED.
• Botulinum toxin or triamcinolone injections: Mild lid retraction (< 2 mm), can be treated by injecting botulinum toxin or triamcinolone into the eyelids.
• Eye drops: Patients with corneal ulcers and other eye symptoms such as dry eyes, require a good amount of lubrication with artificial tears, gels, and ointments.
• Corticosteroids: These drugs reduce inflammation and swelling. They are given orally (by mouth) or intravenously (into a vein) as the first-line treatment in patients with moderate to severe TED.
• Immunomodulators: These are second-line agents used in treating patients who do not respond to steroid therapy or those who have a contraindication for steroid use.
• Immunobiologicals: They are a class of drugs that work by targeting specific components of the immune system, such as IL-6 cytokines. They are often used to modulate or suppress the immune response in autoimmune diseases.

Additionally, ongoing research is exploring disease-modifying treatments that specifically target the inflammatory phase of TED.

Surgical Treatment:

A surgery may be necessary in more severe cases of TED.

• Orbital decompression surgery: This technique enlarges the eye socket, relieves pressure on the optic nerve, and repositions the eye. The goal is to keep vision, eye function, and comfort intact.
• Eye muscle surgery: The affected eye muscles are detached from the eyeballs and reattached in such a way that the eyes are able to move together thereby correcting double vision.
• Eyelid surgery: It can help prevent the eyelids from pushing back too far or from not shutting entirely.

Lifestyle changes:

• Stop smoking and reduce exposure to second-hand smoke
• Use sunglasses in case of light sensitivity
• Use lubricating eye drops
• Use eye mask while sleeping to prevent drying of the eyes
• Wear prescription glasses for double vision
• Sleep with your head elevated to reduce eye swelling and puffiness

If you begin to observe symptoms of TED, such as eye irritation, eye bulging, or the difficulty in fully closing your eyelids, consult your doctor and enquire about the available treatment options.

Clinical research is looking into newer medicines for people living with TED. Clinical trials (which can also be called ‘research studies’) are designed to look at how safe these experimental drugs are and how well they work, and may compare them with treatments that are already available. If you would like to know more about Roche sponsored clinical trials or are interested in taking part in a clinical trial, speak to your doctor or visit the Roche ForPatients clinical trials page Link