OPA1 and Leber hereditary optic neuropathy: RGCs are particularly sensitive to mitochondrial dysfunction, as exemplified by two diseases: Leber Hereditary Optic Neuropathy (LHON), caused by mitochondrial DNA (mtDNA)-linked defects in oxidative phosphorylation (OXPHOS) complex-I [10], and Autosomal Dominant Optic Atrophy (ADOA), caused in most cases by mutations in a nuclear gene encoding the mitochondrial fusion protein OPA1 [11–13].