Graves' ophthalmopathy: I. Simple CT estimates of extraocular muscle volume.

Graves' ophthalmopathy is an autoimmune inflammatory process affecting primarily the extraocular muscles. The enlargement of these muscles is responsible for most of the important manifestations of the disease, including proptosis, lid retraction, diplopia, and optic neuropathy. Recently the optic neuropathy has been shown to correlate with extraocular muscle volume as determined by computed tomography (CT). In the present study simplified measures of the extraocular muscles imaged by CT are described, which also correlate highly with the development of optic neuropathy.