PURPOSE: To report spontaneous visual improvement in a patient with unilateral optic neuropathy due to pituitary metastasis. METHODS: Report of a case. RESULTS: A 54-year-old woman with a history of breast carcinoma lost vision in her right eye to 20/70 without any other symptoms. Six days later, vision spontaneously improved to 20/30. A pituitary mass compressing the right intracranial optic nerve was found on magnetic resonance imaging and the diagnosis of metastatic breast carcinoma was confirmed by biopsy. CONCLUSIONS: Spontaneous visual improvement can occur in the setting of compressive optic neuropathy by a solid mass.