What does it involve?
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 volume of extraocular muscles and orbital fat, causing proptosis or exophthalmos (bulging eyes).
What causes it?
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.
How can it be prevented?
Thyroid orbitopathy is not preventable. An ophthalmic evaluation at the same time as diagnosis of a thyroid problem or before receiving radiotherapy can facilitate better diagnosis and monitoring to detect problems early and prevent complications.
If any of these symptoms appear, even if thyroid disease has not been diagnosed, patients should consult an ophthalmologist for a comprehensive examination.
The most significant risk factor, which plays an important role in the evolution of the disease, is smoking. It is, therefore, essential to stop smoking after diagnosis of a thyroid problem, regardless of whether the eye has been affected.
The condition has a poorly defined onset with orbital inflammation, manifested by eyelid swelling, proptosis, eyelid retraction and, sometimes, strabismus (eye deviation), usually without associated pain.
The progression and severity of the disease is highly variable, in some cases, representing a threat to vision. Once onset has begun, the period of inflammatory activity can last from a few months to two years. After this period, when the condition has stabilised, it is very unlikely that the process will reactivate.
Some symptoms that can be associated with thyroid orbitopathy include:
- Foreign body sensation, ocular irritation and tearing due to corneal exposure
- Double vision caused by strabismus
- Decreased visual acuity due to compression of the optic nerve
- The eye can generally be affected bilaterally, but also unilaterally or highly asymmetrically. It mainly affects women aged between 40 and 60, and its progression is strongly associated with smoking
- Thyroid orbitopathy can even occur before thyroid disease has been diagnosed
The treatment of thyroid orbitopathy depends on the stage of the condition and the problems detected.
In early stages, when the inflammatory changes occur, treatment is aimed at protecting the ocular surface from dryness due to exposure. Anti-inflammatory treatment with corticosteroids is reserved for cases in which inflammation threatens vision.
In some patients, after the inflammatory period, the eyes return to normal, and surgical treatment is not required. But, in other cases, in 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, if necessary, the strabismus and eyelid retraction are corrected.