[Evaluation of extraocular muscle enlargement in dysthyroid ophthalmopathy].

PURPOSE To evaluate the extraocular muscle enlargement in dysthyroid opthalmopathy. METHOD Extraocular muscle enlargement was assessed by orbital computed tomography (CT) in 573 patients with dysthyroid ophthalmopathy in order to investigate the frequency and exact location of extraocular muscle enlargement and the clinical features of related ocular symptoms in patients with dysthyroid ophthalmopathy. RESULTS AND CONCLUSION 187 patients (38% of the total) showed evidence of extraocular muscle enlargement on CT images, and this disorder were more frequent in male patients than in female patients. Extraocular muscle enlargement was also more frequently seen in older patients than in younger patients. Enlargement of a single muscle was found in 55% of the 187 patients, with the most frequently affected muscle being the inferior rectus muscle. When multiple muscles were enlarged, the inferior rectus muscle was the most frequently affected, followed by the medial rectus muscle. Of the clinical findings specific to dysthyroid ophthalmopathy examined in the present study, the incidence of exophthaomos, upper lid swelling, superior limbic keratoconjunctivitis, keratitis, diplopia, and dysthyroid optic neuropathy were significantly increased in patients with dysthyroid ophthalmopathy, indicating a close relationship between these findings and the underlying disease, but the incidence of upper lid retraction was not significantly increased.