With enlargement of the extraocular muscle at the orbital apex, the optic nerve is at risk of compression. The orbital fat or the stretching of the nerve due to increased orbital volume may also lead to optic nerve damage. The patient experiences a loss of visual acuity, visual field defect, afferent pupillary defect, and loss of color vision. This is an emergency and requires immediate surgery to prevent permanent blindness. Pathophysiology
TAO is an orbital autoimmune disease. The thyroid-stimulating hormone receptor (TSH-R) is an antigen found in orbital fat and connective tissue, and is a target for autoimmune assault.On histological examination, there is an infiltration of the orbital connective tissue by lymphocytes, plasmocytes, and mastocytes. The inflammation results  in a deposition of collagen and glycosaminoglycans in the muscles, which leads to subsequent  enlargement and fibrosis. There is also an induction of the lipogenesis by fibroblasts and preadipocytes, which causes enlargement of the orbital fat and extra-ocular muscle compartments. This increase in volume of the intraorbital contents within the confines of the bony orbit may lead to dysthyroid optic neuropathy (DON), increased intraocular pressures, proptosis, and venous congestion leading to chemosis and periorbital oedema. In addition, the expansion of the intraorbital soft tissue volume may also remodel the bony orbit and enlarge it, which may be a form of auto-decompression.
Surgery
Vestibulectomy, during which the nerve fibers to the area are cut out, may be recommended if other treatments have not been found to be effective. There have been no high quality studies looking at surgery as a treatment. While improvement has been noted in 60% to 90%, those who were treated without surgery improved in 40 to 80% of cases. Epidemiology
The percentage of women affected is not entirely clear, but estimates range as high as 16%. Many other conditions that are not truly vulvodynia (diagnosis is made by ruling out other causes of vulvar pain) could be confused with it. Vulvar pain is a quite frequent complaint in womens health clinics. Vulvodynia is a new term in the medical literature. References
External links
Vulvodynia at Curlie