Unilateral optic neuropathy as the initial manifestation of euthyroid Graves' disease

Graves' disease is generally seen in women between the ages of 20 and 50 years. Euthyroid Graves' opthalmopathy is seen in 3% of the patients and 10% of the cases are unilateral. Although optic neuropathy is rare and is seen at the later stages of the disease, it is a detrimental complication. Herein, we report a 43-year-old man with right-sided vision loss who was eventually diagnosed to have optic neuropathy as the initial manifestation of euthyroid Graves' disease. Graves' disease should be considered in the differential diagnosis of optic neuropathy of unknown origin.