Treatments for the hereditary optic neuropathies, including Leber hereditary optic neuropathy and dominant optic atrophy, are limited. In this Review, Nancy Newman summarizes the natural history of hereditary optic neuropathies, and the role of mitochondrial dysfunction in their pathogenesis. She highlights recent advances in the treatment of these disorders, and indicates how insights into the hereditary optic neuropathies could have therapeutic implications for other disorders of presumed mitochondrial dysfunction.