DISEASES AND TREATMENTS

Thyroid orbitopathy

What is thyroid orbitopathy?

Thyroid orbitopathy is an immunological disorder that affects the functioning of the thyroid gland and orbital components, together or separately. It produces an enlargement of the extraocular muscles and orbital fat, causing proptosis or exophthalmos (bulging eyes).

Causes

In most cases, the condition is associated with hyperthyroidism but can also occur in patients with hypothyroidism or even patients without thyroid disease.

It occurs when certain molecules that are present in the thyroid gland and orbit react to the gland and orbital tissue (orbital fatty tissue and extraocular muscles) and inflame them.

Prevention

Thyroid orbitopathy is not preventable. However, ophthalmic evaluation upon diagnosis of thyroid problems or before receiving radiotherapy can facilitate better control and monitoring of the disease for early detection of problems and prevention of complications.

Symptoms

The condition has a poorly defined onset, with orbital inflammation in the form of swollen eyelids, proptosis, eyelid retraction and occasionally strabismus (eye deviation), usually without associated pain. The progression and severity of thyroid orbitopathy is highly variable and may pose a threat to vision in some cases.

After the onset of the disorder, inflammation may last from a few months to two years. Afterwards, when the condition has stabilised, reactivation of the process is highly unlikely.

Symptoms that may be associated with thyroid orbitopathy include:

Sensation of a foreign object, ocular irritation and tearing due to corneal exposure.
Double vision caused by strabismus
Decreased visual acuity due to compression of the optic nerve
The disorder usually affects both eyes, but it may be unilateral or highly asymmetrical. It mainly affects women aged between 40 and 60 years of age, and its progression is closely associated with smoking.

Thyroid orbitopathy may even occur prior to diagnosis of thyroid disease.

BEFORE AND AFTER ORBITAL DECOMPRESSION

Treatment

Treatment of thyroid orbitopathy is administered on the basis of the stage of the condition and the problems detected.

At early stages, when inflammatory changes appear, treatment is aimed at protection of the ocular surface from dryness due to exposure. Anti-inflammatory treatment with corticosteroids is reserved for cases in which inflammation threatens vision.

After remission of the inflammation, some patients’ eyes return to normal and no surgery is required. However, in other cases, at the chronic stage, inflammation is replaced by muscle fibrosis and orbital fat, for which surgical treatment is performed by means of orbital decompression to correct the proptosis. Subsequently, strabismus and eyelid retraction are corrected, when necessary.