Primary optic apparatus germ cell tumors are rare. There have been only 6 cases reported in the literature. Although they often disturb the hypothalamus-pituitary-adrenal axis and cause progressive visual loss, the influence of treatment outcomes on hypothalamic autoregulation has never been mentioned. Here, we report a patient with an optic nerve germinoma who presented with reversible visual and hypothalamic dysfunction, and we discuss the possible mechanisms and pathogenesis.