All About Eyes, For Students

Thyroid Eye Disease Simplified + Bonus: New Update On Research

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What is it?

An autoimmune condition whereby the body attacks the thyroid gland causing it to enlarge and produce more of the thyroid hormone.

An increase in the thyroid hormone leads to increased heart rate, high blood pressure,  excess sweating, weight loss, fatigue, heat intolerance, and loss of hair.

Thyroid eye disease is also known as graves disease. 

How it affects the eye?

The eye tissue contains proteins similar in structure to those in the thyroid gland. Hence, the immune system attacks the eye muscles causing them to enlarge leading to an imbalance in eye control. Double vision becomes one of the main symptoms of thyroid eye disease. Other symptoms include bulging of the eyes or proptosis giving a startled look, dry eyes due to inability to complete closure of the lids due to proptosis, blurry vision, pressure pain, and pain on eye movement if the optic nerve swells up. 

However, these symptoms range from mild to severe and only 10%-20% are threatening.

Thyroid eye disease usually presents in two stages

  1. Active phase(lasting 1-3 years): known as the inflammation and swelling phase. Symptoms such as pain, proptosis, dry eyes, and double vision continue to progress.
  2. Non Active phase: inflammation and pain settle but may flare up again as thyroid eye disease is an ongoing condition. Proptosis and double vision may decrease but stabilise. 

Severe complications:

Inflammation of the eye muscles can put pressure on the optic nerve causing it to swell. If left untreated, vision loss is irreversible. 

Incomplete closure of lids, not only causes dry eyes but corneal irritation and ulcers which can be very painful.

Risk factors:

Women are at higher risk than men

Smoking (research indicates that smoking has an impact on specific genes expressed in thyroid disease and cessation of smoking has a certain effect on the improvement of thyroid function.)

Graves disease (enlargement of the goiter and excess secretion of thyroid hormone)

Hyperthyroidism (excess secretion of thyroid hormone)

Hypothyroidism or Hashimoto (minimal secretion of thyroid hormone)

The weakened immune system for example diabetes or arthritis.

Although the above three conditions present strong risk factors they don’t directly cause thyroid eye disease. They have different pathologies and treatment regimes. Additionally, they don’t necessarily occur at the same time.

Usual Examination: 

  • Vision testing
  • Measurement of the eye pressure
  • Eyelid measurements
  • Ocular motility and cover testing (quick test assessing eye movements, eye turns and double vision)
  • Colour vision
  • OCT RNFL (Optic nerve scan) 
  • Visual field test if the optic nerve is affected.

Diagnosis:

Blood test checking the thyroid levels and thyroid function

CT scans of the thyroid gland and the eye orbit

Treatment:

Active Stage

  • careful monitoring as symptoms and signs continue to change and progress. 
  • Immediate treatment of dry eyes to relief irritation, redness, corneal ulcers and light sensitivity. 
  • Occlusion of one eye using an eye patch to eliminate disturbances from double vision
  • Treatment of the underlying thyroid condition is important but medicational treatment of thyroid eye disease will involve immunosuppressants and steroids to treat reduce the swelling. 
  • radioactive iodineto eliminate hormone-producing cells, and further treat advanced swelling. Careful monitoring should always be undertaken as radiation therapy can sometimes increase dry eyes. Also, it can only be used twice in a person’s lifetime. Hence it is not always the treatment of choice.
  • surgical treatment during active phase is often avoided as eye tissues are constantly changing. 

Non-active Stage

  • Symptoms may gradually and spontaneously resolve. But, residual scarring is very likely.
  • Surgery may be performed to correct residual muscle imbalance causing double vision and retract the eye into its original position.

What can you do?

Apply cool compresses to your eyes. The extra moisture may provide relief.

Wear sunglasses. Wearing sunglasses helps protect the eyes from the sun and wind. 

Use lubricating eyedrops. Eyedrops, like artificial tears, may help relieve dryness and scratchiness. Be sure to use eye drops that do not contain redness removers. A lubricating gel can be used before bed to prevent the cornea from drying out because your eyelids may not cover the entire eye when sleeping.

Elevate the head of your bed. Keeping your head higher than the rest of your body may reduce swelling and may help relieve pressure on your eyes.

What does new research say?

  • Smoking cessation has an immediate effect on improvement of the condition as smoking has been shown to interact with the main gene of the condition.
  • Teprotumumab or (tepezza) approved by FDA for use in the US only, is an intravenous medication that inhibits the protein insulin-like growth factor-1, which is believed to a play as significant role in the development of the disorder. Affected individuals have shown significant improvement in proptosis, double vision, and overall quality of life when taking Teprotumumab.
  • Selenium supplements have been recommended in early mild stages of the condition to slow the progressionimprove the appearance and visual function of the eyes.

Differential diagnosis:

Orbital cellulitis: infection in the eye socket with pain, swelling and proptosis. Common in children

Orbital myositis: inflammation of the eye muscles presenting with pain and diplopia. Commonly occurs after systemic infection.

Myasthenia Gravis: an autoimmune disease causing muscle weakness. Symptoms include droopy eyes, double vision, shortness of breath, difficulty with speech, and fatigue.

Sources:

https://www.umkelloggeye.org/conditions-treatments/thyroid-eye-disease

https://journals.lww.com/coophthalmology/Abstract/2018/11000/Thyroid_eye_disease__what_is_new_to_know_.9.aspx

https://www.nature.com/articles/s41574-019-0311-6

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