A 40-year-old woman who recently received a diagnosis of Graves' disease comes for a follow-up visit. She has been taking methimazole, at a dose of 10 mg daily, and is now euthyroid, but for the past 3 months, she has had bothersome eye symptoms, including redness, tearing, grittiness, photophobia, diplopia at the extremes of gaze, and ocular pain with eye movements. She smokes 10 cigarettes per day. Examination reveals exophthalmos, swelling of periorbital tissues, and limitation of eye movements. How should Graves' ophthalmopathy be managed?