ABSTRACT
The best description of the natural history of Graves’ ophthalmopathy (GO) is given by Rundle (1-3). He performed sequential quantitative measurements of eye changes in patients who did not receive any specific treatment of GO. From their studies, a curve can be constructed reflecting the natural course of the severity of GO (Fig. 1A). An initial dynamic phase is followed by a late static phase. The dynamic phase starts with a stage of increasing severity. Exophthalmos develops in conjunction with restriction of
eye muscle motility and widening of the lid aperture. In general, for every increase of proptosis of 1 mm, elevation is restricted by 4-5. After having reached the peak of disease severity, the eye changes spontaneously improve to a certain extent, the stage of reconvalescence. When the eye changes remain stable, the disease has come in its end-stage, the static phase. Note that in 75% of patients, the eye changes have not completely resolved, and remaining eye changes may still be disfiguring and incapacitating. Histologic examination of orbital tissues in the early stages demonstrate lymphocytic infiltration, activated fibroblasts, and edema in extraocular muscles and orbital fat. In the late stages, there is dense collagen, fibrosis, and fat accumulation (4-6). The findings in the early stages reflect the active ongoing inflammation caused by the autoimmune reaction, whereas findings in the late stages indicate the inactive, fibrotic, burnt-out endstage of the disease. We hypothesized that upon spontaneous resolution of the eye changes at the stage of reconvalescence, the activity of the eye disease must already be on the decline. Consequently, we propose an additional curve describing the natural history of GO in terms of disease activity (Fig. 1B) (7).
