What is Thyroid Eye Disease?
Thyroid Eye Disease (TED) is an inflammatory disorder causing the muscles and fatty tissue in the orbit surrounding the eyes to swell. It is caused by a systemic auto-immune disorder associated with thyroid function, that results in the body’s immune system attacking the tissue surrounding the eyes.
Causes of Thyroid Eye Disease
The majority of cases of TED are associated with Grave’s Disease which causes excess thyroid hormone production (hyperthyroidism). A much lower percentage of cases are associated with reduced thyroid hormone production (hypothyroidism), such as Hashimoto’s Thyroiditis, or even normal functioning of the thyroid. Common alternative names for TED include Grave’s orbitopathy/ophthalmology and thyroid orbitopathy.
Grave’s Disease is more common in patients that already suffer from other auto-immune disorders, such as Myasthaenia Gravis, Lupus, Diabetes and Rheumatoid Arthritis. Smoking doubles the risk of developing Grave’s Disease and greatly increases the risk of developing TED in patients that already have Grave’s Disease. Females have a much higher rate of developing TED than males and stress has been shown to worsen symptoms.
Signs/Symptoms of Thyroid Eye Disease
The most common signs and symptoms of TED that are related to the enlargement and tightness of the muscles and tissue in the orbit surrounding the eyes include:
- red eyes
- dry eyes
- swelling surrounding the eyes
- tight eyelids that may become retracted
- inability to completely close the eyes
- misalignment of the eyes (strabismus) causing double vision
- restricted eye movement
- pain on eye movement
- the appearance of the eyes protruding from the eye socket (proptosis)
In severe/advanced cases, vision may be affected due to compression of the optic nerve at the back of the eye by the swollen muscle and tissue, or damage to the cornea due to lid retraction and protrusion of the eye. Symptoms usually occur in both eyes but may be more severe in one than the other.
Assessment and Treatment of Thyroid Eye Disease
The initial approach to the treatment of TED is to maintain good general health and achieve normal thyroid function through systemic treatment. Smoking should be ceased in all circumstances. Eye-specific treatment will depend on the patient’s individual symptoms and can range from supportive treatment to medical treatment and finally to surgical treatment in advanced cases.
Supportive treatment includes:
- eliminating stress and smoking
- use of lubricating eye drops to address dry, exposed eyes
- contact lenses to reduce exposure and damage to the cornea
- prisms in glasses to correct double vision
- sleeping with head elevated to reduce swelling around eyes
Medical treatment includes:
- the use of corticosteroids, such as Prednisone (orally or intravenously) to reduce tissue swelling and reduce immune system activity
- thyroid radiotherapy to suppress thyroid activity
- orbital radiotherapy to reduce swelling of the muscles and tissue surrounding the eyes
Surgical treatment includes:
- orbital decompression surgery to relieve pressure being placed on the optic nerve and it’s blood supply
- surgical correction of eyelid retraction to lengthen the eyelids or their connective tissue and improve their ability to close
- surgical correction of eye misalignment if prism glasses cannot adequately correct double vision