Thyroid Eye Disease (TED)

What Is Thyroid Eye Disease?

Thyroid eye disease (TED), also called thyroid-associated orbitopathy, thyroid ophthalmopathy, or Graves’ ophthalmopathy, is a condition that mainly affects patients with hyperthyroidism, but it may occur in clinically euthyroid patients, and patients with hypothyroidism and Hashimoto’s thyroiditis as well. Only 40 percent of the disease starts simultaneously with the onset of hyperthyroidism. The other 20 to 40 percent of orbitopathy begins before or after thyroid dysfunction. Thyroid eye disease occurs in patients with thyroid hormone imbalance, which commonly affects females, but it is more serious in males. The most common risk factor for thyroid hormone imbalance is smoking as it leads to an imbalance in thyroid hormones. The severity will depend upon the number of cigarettes per day. The risk increases with cigarette consumption.

What Causes Thyroid Eye Disease?

It is an autoimmune disease where the patient may also be suffering from other autoimmune diseases, such as rheumatoid arthritis. It is usually associated with an over-active thyroid gland caused by Grave’s disease. Grave’s disease causes an increase in thyroid hormone production and thereby causes hyperthyroidism. The orbital fibroblast present in the eyes swells due to thyroid hormone imbalance. This results in the accumulation of water in eye muscle, which leads to the bulging of eyes called proptosis.

What Are the Signs and Symptoms of Thyroid Eye Disease?

The signs and symptoms of thyroid eye disease or thyroid orbitopathy include:

1. Bulging eyes.

2. Prominent blood vessels in the eyes.

3. Eye congestion or redness.

4. Swelling of eyelids.

5. Double vision.

6. Difficulty in seeing distant objects.

7. Difficulty in seeing a particular color.

8. Limited eye movement.

9. Retraction of the upper eyelid.

10. Incomplete or infrequent blinking.

11. Edema of the lower lid.

12. Conjunctival infection or redness.

13. Abnormal pigments over the upper eyelid.

14. Abnormal pupil.

How Is Thyroid Eye Disease Diagnosed?

TED is diagnosed based on the presence of characteristic signs or symptoms. If exhibiting any of the following signs or symptoms, kindly consult an ophthalmologist immediately.

A clinical examination will be performed to identify any of the following:

• Bulging eyes.

• Restricted eye movement.

• Defective vision- normal and color vision.

• Abnormal color vision.

• Pupil examination.

• Intraocular pressure.

• Presence of infection.

• Exposure to keratopathy.

Blood Test:

• Presence of thyroid antibodies in the blood.

If the doctor suspects thyroid eye disease, one might have to undergo the following investigation:

• Orbital Sonography- to measure the structure and size of the affected eye.

• Other Imaging Tests-Computed tomography (CT) scan of the orbit, and magnetic resonance imaging (MRI) of the orbit.

• Orbital biopsy, if needed.

How Can Thyroid Eye Disease Be Treated?

There are three ways to treat thyroid eye disease as mentioned below:

1) Non-Medical Management -

• Avoid Smoking: In this type of management, the most important factor is smoking. Those who are at risk of thyroid hormone imbalance should stop smoking completely without further delay. If one quits smoking, the chance to develop thyroid orbitopathy will reduce automatically by 50 percent. Passive smoking and smoking cessation will avoid the worsening of symptoms. The risk of complications will be reduced on its own.

• Physical Activity: Physical activity is a significant factor. Daily exercise is a must to reduce the risk of thyroid orbitopathy. Patients with thyroid eye disease are advised to sleep with the head end of the bed elevated.

• Other Systemic Diseases: Keeping systemic diseases like diabetes and hypertension under control is an important factor in controlling thyroid hormone imbalance.

2) Medical Management -

Antithyroid drugs will help reduce the increased levels of thyroid hormone. Additionally, oral or intravenous steroids play an important role in the control of excessive thyroid hormone. If patients have severe lid edema, they may benefit from systemic steroids such as Methylprednisolone. Cold compression with ice and nonsteroidal anti-inflammatory drugs (NSAIDs) may help to reduce symptoms. And at night, patients should use a topical eye lubricant to reduce discomfort.

3) Radiotherapy -

It is also one of the modalities to treat thyroid eye disease. Radiation to the orbit will benefit those patients with active disease. For patients who are not responding to oral steroids, radiotherapy will be useful. However, radiotherapy is contraindicated in patients with diabetes.

4) Surgery:

Once the infection and symptoms have subsided, surgery is frequently carried out as part of rehabilitation treatment. and may involve:

• Decompression surgery (removing soft tissue and bone behind the eye to create more space).

• Eye muscle surgery (for correcting severe double vision).

• Eyelid surgery to improve the function and structural appearance of the eyelids.

What Are the Complications of Thyroid Eye Disease?

• Thyroid Eye Disease and Squint: Thyroid eye disease can lead to squinting. Squint is the deviation of the eyes. It can be in any direction. It can be an inward deviation, or it can be an outward deviation. Deviation of the eye can lead to double vision. To avoid double vision, patients can use prisms. Prisms can relieve diplopia. If double vision is not getting better with prisms, patients should undergo surgery. Surgery is performed on extraocular muscles.

• Lid Retraction and Lagophthalmos: The inability to close eyelids while sleeping (lagophthalmos) can be treated in the active phase by Botulinum toxin injection. Once the condition is stable, patients can plan surgery such as levator recession or lid lengthening.

What Are the Prognostic Determinants for Thyroid Eye Disease?

1. Age - The prognosis is worse in older patients.

2. Gender - Females are more prone to TED.

3. Severity - The disease is more severe in males compared to females.

4. Race - The disease is more severe in Caucasian patients than in Asian patients.

5. Lifestyle - Smoking causes severe TED.

6. Diabetes - Diabetes increases the risk of severe TED due to thyroid hormone imbalance.

If one has any concerns with thyroid hormone levels or any symptoms or signs, as described in this article, it is best to consult an ophthalmologist as early as possible to diagnose it in the early stage. Thyroid ophthalmopathy is a treatable condition if it is diagnosed in the early stage. If not treated early, the risk of complications and the severity of the disease increases. Severe disease can lead to loss of eyesight.

Conclusion

Anyone can develop thyroid eye disease, but people with Graves' disease or a thyroid problem are more prone to develop it. Contact the healthcare provider if one experiences impaired vision, frequent watering, dryness, or a gritty feeling in the eyes. Early detection and treatment of thyroid eye disease are crucial if one wants to minimize any potential harm. It is imperative to quit smoking if a person wants to decrease the risk and severity of thyroid eye disease.