The Maximum width of four rectus muscles (MR, LR, IR, SR) was measured on CT films and followed for 1-2 years in 304 eyes of 160 patients with dysthyroid ophthalmopathy. Based on these parameters, steroid therapy with 100-150 mg betamethasone, intravenously and orally, 1.5 Gy Lineac radiation therapy was given to the retrobulbar tissue from two directions repeated for 10 days and combination therapy consisting of the above two therapies given at the same time were evaluated. Combination therapy yielded the best results. Steroid therapy showed little effect on MR, but remarkable effect on SR. It was speculated that different portions of the rectus muscles may be related to different responses of rectus muscles to different treatment regimen.