Thyroid Disorders  Thyroid Eye Disease
Graves' disease and the associated eye changes (Graves' orbitopathy) are perplexing to the affected patient.
The eye symptoms usually occur at the same time as the thyroid disease, however they may precede or follow the obvious symptoms of the thyroid abnormality.
Most patients with thyroid abnormalities will never be affected by eye disease and some patients only mildly so.
Although the incidence of eye disease associated with thyroid dysfunction is higher and more severe in smokers, there is no way to predict which thyroid patients will be affected.
In addition, while eye disease may be brought on by thyroid dysfunction, successful treatment of the thyroid gland does not guarantee that the eye disease will improve as well, and no particular thyroid treatment can guarantee that the eyes will not continue to deteriorate.
Once inflamed, the eye disease may remain active from several months to as long as three years.
Subsequently, there may be a gradual or, in some cases, a complete improvement.
While rare, recurrence of the eye disease can happen and may coincide with inadequate control of thyroid hormone levels.
Medical Treatment
Early eye symptoms, which may include dryness, redness, itching, swelling of the lids and inability to wear contact lenses, are usually mild.
Some patients find these symptoms to be particularly irritating at night and under certain conditions such as air conditioning, hot air heating and windy days.
A few patients will develop double vision (diplopia), which is the result of asymmetric scarring and inflammation of the muscles that control eye movement.
Since most patients develop mild symptoms, they are often misdiagnosed with an ocular allergy.
Therefore, Graves' disease patients should be followed by an ophthalmologist familiar with the condition and available treatments.
Patients with mild symptoms can often be successfully treated with frequent application of lubricating eye drops and wearing eye covers at night.
Humidification of room air can prevent drying of the eyes, and wrap-around polarizing sunglasses can also help relieve glare.
Diplopia can be alleviated with prism lenses while awaiting either spontaneous improvement or surgical correction.
Temporary plastic prisms are available which are applied to glasses and changed as needed.
Prednisone, a steroid medication, may be taken orally to provide temporary relief from pain, swelling and redness, although side effects of the medication may limit the use of prednisone and related drugs.
Vision loss due to pressure on the optic nerve is the most severe form of the disease.
Fortunately, this condition is rare, affecting less than 5% of patients with Graves' orbitopathy.
Treatment with prednisone, radiotherapy, and/or surgery may be required to restore vision.
Overall, it is important to keep in mind that eye disease associated with Graves' disease will only improve gradually.
Surgical Management
If the eye condition does not improve or deteriorates despite treatment, surgery may be required.
Retracted and puffy eyelids can alter a person's appearance and increase the risk of cornea drying.
Corrective eyelid surgery can alleviate the problem through adjustable loosening of the eyelid muscles, as well as removal of scar tissue, excessive fatty tissue and skin to place the eyelids into a more normal position.
Surgery may also be necessary to correct diplopia when this problem has not resolved either spontaneously or with prism lenses.
This surgery entails detaching and repositioning the muscles that control eye movement onto the eyeball to improve ocular alignment and minimize double-vision.
The enlargement of tissue behind the eye may sometimes cause significant forward protrusion of the eye (exophthalmos), which produces the characteristic appearance, worsens the symptoms, and causes ocular exposure.
Swelling in the orbit may actually contribute to vision loss as pressure increases on the optic nerve.
Surgical procedures to relieve pressure on the optic nerve improve vision and allow the eye to settle back to a more normal position.
Orbital decompression is indicated in patients with significant exophthalmos, visual loss, or severe exposure of the corneas.
Sometimes careful resection of fat behind the eyeball is performed in conjunction with, or in place of bone decompression.
For most patients, surgery is performed under general anesthesia and usually requires an overnight hospital stay.
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