Background and ophthalmic features of patients with thyroid eye disease with dysthyroid optic neuropathy in Japan

To evaluate the background and ophthalmic features of patients with dysthyroid optic neuropathy (DON) requiring prompt diagnosis and treatment. This study included 72 eyes of 42 patients with DON (males, 17; females, 25; age, 58 ± 12 years). Patients underwent smoking history assessment, autoantibody measurement (thyrotropin receptor antibodies (TRAbs) and thyroid-stimulating antibodies (TSAbs)), ophthalmic examination, and orbital magnetic resonance imaging (MRI). Of the 42 patients, 40 had Graves’ disease and 2 had hypothyroid Graves’ disease. Six and five patients had diabetes and hepatitis, respectively. Twenty-seven patients (64.3 %) had smoking histories. TRAbs and TSAbs were positive in 31 of 37 (83.8 %) and 38 of 38 (100 %) patients tested, respectively. Best-corrected visual acuity was less than 20/200 in 15 eyes (20.8 %) and 20/25 or better in 19 eyes (26.4 %). All eyes exhibited visual field loss. Average proptosis was 18.1 ± 2.8 mm. The optic disc was normal in 36 eyes (50 %). Orbital MRI revealed optic nerve compression due to rectus muscle enlargement in all patients. Eyes with DON consistently exhibited visual field loss, positive TSAb, and compressed optic nerve on orbital MRI. Thus, those tests are recommended for patients with thyroid eye disease, particularly when DON is suspected.