Mitochondrial Control of Myelination, Bioenergetics, Oxidative Stress, and the Pathogenesis of Optic Neuropathies.

Myelination, mitochondrial bioenergetics, and oxidative stress are usually discussed as separate problems in optic nerve disease. This review draws them together and reads the published evidence through a single variable, the balance between the energy a retinal ganglion cell (RGC) axon spends and the energy its mitochondria can supply. We review the role of myelin in conduction and axonal support, the mitochondrial cost of building and maintaining it, the vulnerability of oligodendrocytes and myelin to oxidative injury, and the nuclear control of mitochondrial output. We summarize the inherited optic atrophies linked to OPA1, OPA3, AFG3L2, SPG7, and TMEM126A, and set these primary mitochondrial disorders against the immune-mediated demyelinating optic neuropathies. Published studies already support several parts of this picture, including the energetic cost of demyelination, the mitochondrial dependence of RGC axons, and oxidative injury in inflammatory lesions. Drawing on that evidence, we propose, as a testable hypothesis rather than a settled mechanism, that optic nerve degeneration is favored when axonal ATP demand outruns mitochondrial supply, most sharply where the axon crosses from its unmyelinated to its myelinated segment near the lamina cribrosa. We use this framework to separate initiating lesions from disease modifiers and downstream consequences, and to set out therapeutic predictions open to experimental and clinical tests.