Further management of this condition with novel drug idebenone (and CO Q 10) can be undertaken, especially in adult patients with the m.11778G>A ND4 mutation, as in our patient as these patients would otherwise have the worst visual outcomes in their natural course. A knowledge of ethambutol-induced conversion in LHON as in our patient can help prompt suspicion of LHON. Keywords: Ethambutol-induced optic neuropathy; idebenone; Leber's hereditary optic neuropathy EN Ethambutol-induced optic neuropathy idebenone Leber's hereditary optic neuropathy 2760 2762 3 07/15/22 20220701 NES 220701 Leber's hereditary optic neuropathy (LHON) is a maternally inherited disease which is blinding with variable penetrance. [Extracted from the article]