Graves' disease is generally associated with a typical ophthalmopathy. The occurrence and intensity of this ophthalmopathy are not related to the course of hyperthyroidism. Pituitary ophthalmotropic factors, other than thyrotropic hormone, are considered to be the cause of the exophthalmos.3
Two principal clinical types of exophthalmopathy have been described, namely, the simple and the malignant exophthalmos; however, most of the patients show a mixed picture, presenting some characteristics of each one. In severe exophthalmos, underlying edema and cellular infiltration of the conjunctiva and structures about the eye are clinically obvious.
There have been many hypotheses on the mechanism of the ophthalmopathy of Graves' disease. It is now generally accepted that the proptosis is due to an increased volume of the retrobulbar tissues of the eye.3,9 Several factors may play a part in the filling of the orbit: an increase in retrobulbar fat,5,9 an increase in the size
PARISIER H, HOUSSAY AB, MORALES AG, ARATA AF, FUNES JC, ALTSCHÜLER N. Removal Rate of Na24 from Human Orbit in Exophthalmic Patients. Arch Ophthalmol. 1963;69(4):479-483. doi:10.1001/archopht.1963.00960040485011