Cyproterone has antiandrogenic, antigonadotropic, and progestagenic activity. High-dose preparations are used for treatment of prostate cancer and for treatment of hypersexuality. We describe a patient who was referred to our clinic with slowly progressive unilateral proptosis and blindness of the left eye. He had been treated with high-dose cyproterone actate (CPA) for 23 years. An obvious proptosis and exodeviation of his left eye was noted on ophthalmic examination. Fundoscopy showed left optic atrophy. The literature suggests a link between long-term high-dose exogenous progesterone agonist exposure and the progression and/or development of meningioma. MRI of the brain was performed and revealed multiple meningiomas. One large meningioma located in the anterior temporal lobe extended into the left orbit and caused the proptosis and blindness. Treatment with CPA was stopped and follow-up imaging 11 months later showed a significant decrease in size of the largest meningiomas.