Thyroid eye disease (TED) often occurs in people who develop an overactive thyroid (about 40% of cases). It can also develop some time after an overactive thyroid gland has been treated (again, in about 40% of cases), or less commonly in can develop in people who don’t have an overactive thyroid (20% of cases).
Thyroid eye disease in an autoimmune disease, whereby cells in the body which normally protect the body against infection, (antibodies) mistakenly attack the thyroid gland and the soft tissues in the eye socket. The thyroid gland produces more thyroid hormone as a result and the soft tissues in the socket swell up making the eyes more prominent and in more severe cases preventing the muscles which more the eye from working properly. If the tissues in the eye socket swell up sufficiently, then the excessive pressure can compress the optic nerve and lead to loss of vision.
The usual age of onset is 30-50 years and women are more frequently affected than men (by a ratio of 4:1). Smoking is an important risk factor, and is responsible for a 7-8 fold increase in the likelihood of developing TED.
The symptoms of TED start with ocular irritation, aching behind the eyes, red eyes and changes in the appearance of the eyes (the eyelids can become retracted, making the eyes look more open and the eyes can be pushed forwards by the soft tissue swelling in the eye socket).