Metastatic optic nerve sheath calcification with optic atrophy associated with untreated hyperparathyroidism

•Etiology of optic nerve sheath calcifications is unclear.•Visual loss due to optic nerve sheath calcifications has been reported infrequently.•Case presented with visual loss, hypercalcemia, optic nerve sheath calcifications.•Demonstration of calcification in the setting of untreated hyperparathyroidism.•Consider hypercalcemia and occult parathyroid adenoma as causes of calcification.