Background: Acquired copper deficiency in adults is associated with a subacute to chronic progressive myeloneuropathy and optic neuropathy. Objective: To describe an individual after gastric bypass surgery who developed a chronic progressive myeloneuropathy, an acute optic neuropathy, along with anemia and leukopenia. Design: Case report. Setting: Academic center. Patient: A 55-year-old woman, following gastric bypass surgery 22 years earlier, developed progressive numbness, weakness, and sphincter disturbance over 6 years. She awoke one morning with bilateral blindness. Examination findings showed evidence of severe myelopathy and peripheral neuropathy. Main Outcome Measures: Magnetic resonance imaging, optical coherence tomography, electrophysiologic studies, nerve and muscle biopsy specimens, and vision testing. Results: Over 1 year of follow-up, copper infusion therapy seemed to stabilize the progressive myeloneuropathy and improved leukopenia and anemia. It had no effect on the optic neuropathy. Optic nerve tissue injury was observed on magnetic resonance diffusion tensor imaging and on optical coherence tomography. Conclusions: Copper deficiency should be considered in cases of atypical optic neuropathy. Serum copper levels should be monitored in patients with a compatible neurologic syndrome who have undergone gastric bypass surgery. Although visual acuity did not improve after copper infusion in our patient, prompt recognition of copper deficiency may prevent further deterioration.