Vision (V) evaluates the visual repercussion particularly due to the development of dysthyroid optic neuropathy. This is assessed through visual acuity, pupillary reflexes, color vision, visual fields, optic nerve examination, and visual evoked potentials. Most of these tests should be performed in all patients, as optic neuropathy frequently occurs in patients with little or no proptosis. CT scans may be necessary in selected cases to confirm the presence of an orbital apex syndrome or before surgical decompression (Figure 1 ).
One study, as an example, evaluated 237 patients with newly diagnosed Graves' hyperthyroidism who were treated with thionamides [ 1 ]. At initial presentation, the majority ( percent) of patients had no ocular involvement, whereas mild, moderate-to-severe, and sight-threatening orbitopathy were present in 20, , and percent of patients, respectively. During the 18-month follow-up period, progression to moderate-to-severe orbitopathy occurred in percent of patients with no orbitopathy at baseline and in percent of patients with mild activity at baseline. In contrast, 58 percent of patients with mild disease at baseline experienced complete remission.