In several human diseases caused by mutations in genes essential for mitochondrial function, including approximately 90% of Leber’s hereditary optic neuropathy cases with point mutations in mitochondria DNA [47] and 75% of autosomal dominant optic atrophy patients with mutations in OPA1 [48,49], RGCs are the most sensitive neurons and die as diseases progress. This evidence concerns the gene OPA1 and hereditary optic neuropathy.