ARTICLE Sir, Last year we reported our experience on idebenone therapy in patients with Leber’s herediatary optic neuropathy (Carelli et al. , 2011), presenting results similar with those obtained by the Rescue of Hereditary Optic Disease Outpatient Study (Klopstock et al. , 2011). We now report, for the first time, on the administration of idebenone in seven consecutive patients with dominant optic atrophy carrying OPA1 mutations in an open-label trial. Dominant optic atrophy is one of the most frequent hereditary optic neuropathies, characterized by degeneration of retinal ganglion cells leading to loss of central vision, and is currently considered untreatable (Carelli et al. , 2004; Yu-Wai-Man et al. , 2011). The majority of patients with dominant optic atrophy carry heterozygous mutations in the OPA1 gene (Alexander et al. , 2000; Delettre et al. , 2000), which encodes for a mitochondrial dynamin-like GTPase mainly involved in fusion of the mitochondrial inner membrane, control of apoptosis and maintenance of mitochondrial DNA and oxidative phosphorylation (Landes et al. , 2010). Clinical expression of dominant optic atrophy is mostly limited to optic neuropathy with variable severity (Carelli et al. , 2004; Yu-Wai-Man et al. , 2011), ranging from severe congenital optic atrophy to mild cases (Barboni et al. , 2010). Visual loss affects central vision with colour perception defects and temporal optic disc atrophy because of early involvement of the papillomacular bundle. The natural history of dominant optic atrophy is a relentless and slowly progressive visual loss, which may stabilize usually without spontaneous recovery of vision (Kjer, 1959; Votruba et al. , 1998; Carelli et al. , 2004; Yu-Wai-Man et al. , 2011). A subgroup of patients presents a multi-system disease, defined as dominant optic atrophy ‘plus’, involving the central and peripheral nervous system and skeletal muscle …