Exophthalmos is a condition where the eyeballs protrude, typically as a result of thyroid disease causing inflammation and swelling of the tissues around the eye. Surgery for exophthalmos involves removing some of the bone or fat next to the eye, in order to make more space for the swollen tissues and allowing the eyeball to move back into place. Eye muscle and eyelid surgery may also be required to restore normal function and vision to the eyes.
In Grave's disease, altered thyroid metabolism occurs, with the gland becoming overactive in a condition known as hyperthyroidism. The thyroid may increase in size, causing a swelling in the neck known as a goiter, and up to half of people with Grave's might also develop thyroid eye disease with some degree of exophthalmos. In thyroid eye disease, the tissues and the muscles around the eye become swollen. As well as the eyeballs being pushed forward, so that the corneal surfaces are no longer protected by the eyelids, there is also a risk that the optic nerve connecting the eyeball to the brain may become damaged. The swollen eye muscles may also become stiff so that the eyes no longer move and focus normally.
Exophthalmos surgery is usually only carried out in severe cases, after treating the associated thyroid condition and if non-surgical treatments to reduce the swelling, such as medication and radiotherapy, have failed to work. Mild cases of exophthalmos may resolve by themselves over time. When the optic nerve is at risk of damage, or the cornea is becoming dry and ulcerated as it is no longer covered by the eyelid, then exophthalmos surgery is typically required. Sometimes exophthalmos surgery is needed because patients are distressed by the appearance of their eyes or there is pain caused by the swollen eye tissues.
The main type of exophthalmos surgery is known as orbital decompression, and this can involve the removal of bone or fat, or both, from around the eye. Each of the bony chambers, known as orbits, which contain the eyeballs have four sides: a roof, a floor, and an inner and outer wall. There are a number of methods of exophthalmos surgery, which can involve removing bone from different sides of the orbit, but one common procedure is to enter the orbit through a small incision in the eyelid and to take bone from both the inner and outer walls, together with some fat. Sometimes, a type of keyhole surgery can be used, where a telescope-like instrument is introduced through the nose. Normally, exophthalmos surgery requires only a single night spent in the hospital, and healing occurs fully after only a few months.